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Academic literature on the topic 'Randomised controlled trials'

Author: Grafiati

Published: 4 June 2021

Last updated: 20 February 2023

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Journal articles on the topic "Randomised controlled trials"

1

Mechtouff, Laura, and Pierre Durieux. "Controlled randomised trials." Sang thrombose vaisseaux 33, no. 4 (August 2021): 155–62. http://dx.doi.org/10.1684/stv.2021.1180.

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PHILLIPS, R., and T. ROTHENBERG. "Randomised controlled trials." Archives of Disease in Childhood 77, no. 1 (July 1, 1997): 91. http://dx.doi.org/10.1136/adc.77.1.91f.

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Winter, George. "Randomised controlled trials." British Journal of Midwifery 25, no. 5 (May 2, 2017): 288. http://dx.doi.org/10.12968/bjom.2017.25.5.288.

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Geddes, John. "Randomised controlled trials." British Journal of Psychiatry 205, no. 1 (July 2014): 43. http://dx.doi.org/10.1192/bjp.bp.111.100677.

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De Hert, Stefan, and Luc De Baerdemaker. "Randomised controlled trials." European Journal of Anaesthesiology 31, no. 9 (September 2014): 450–51. http://dx.doi.org/10.1097/eja.0000000000000039.

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Goadsby, Peter J. "Randomised Controlled Trials." Cephalalgia 20, no. 1 (February 2000): 71. http://dx.doi.org/10.1046/j.1468-2982.2000.00008.x.

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Stevens, Ian. "Randomised Controlled Trials." Physiotherapy 83, no. 12 (December 1997): 655–56. http://dx.doi.org/10.1016/s0031-9406(05)65957-3.

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Evans, Jennifer. "Randomised controlled trials." Eye 9, no. 6 (November 1995): 684–85. http://dx.doi.org/10.1038/eye.1995.179.

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Newman, M. "Randomised controlled trials." Journal of Epidemiology & Community Health 48, no. 4 (August 1, 1994): 423–24. http://dx.doi.org/10.1136/jech.48.4.423-a.

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NEWCOMBE, R. "Randomised controlled trials." Postgraduate Medical Journal 75, no. 885 (July 1, 1999): 447. http://dx.doi.org/10.1136/pgmj.75.885.447d.

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Dissertations / Theses on the topic "Randomised controlled trials"

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Ulucanlar, Selda. "Randomised controlled trials and equipoise." Thesis, University of Bristol, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.535188.

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Caldwell, Patrina Ha Yuen. "The Recruitment of Children to Randomised Controlled Trials." University of Sydney. Paediatrics and Child Health, 2003. http://hdl.handle.net/2123/579.

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Abstract Background The randomised-controlled trial (RCT) provides the best evidence for evaluating treatment effects and is accepted as a gold standard for clinical and regulatory decision making (1;2). One of the major challenges to the conduct of RCTs is the recruitment of adequate numbers of participants. Inadequate numbers reduce the power of a study to detect statistically significant treatment effects, and may cause delays, increased costs and failure to complete trials. The need for clinical trials in children has been increasingly recognised by the scientific community, resulting in increased demands for the inclusion of children in trials. For several reasons, recruiting children to trials is more challenging than recruiting adults, as consent issues are more difficult because parents make decisions about trial participation on behalf of their child. Despite general professional and community support for paediatric clinical trials, parents and paediatricians express reluctance when their own child or patient is asked to participate. Although researchers working with children commonly experience difficulty with recruiting children to RCTs, little is known about this very important subject. The method by which potential participants are approached for trial participation, the influence of their health care provider and the attitude of potential participants (or their parents, in the case of children), are critical to the understanding of the decision making process for trial participation. This thesis is one of the first major attempts to explore the issues surrounding the recruitment of children to RCTs, and is divided into four studies which address these issues. Methods Recruitment strategies used to encourage participation in randomised controlled trials (systematic review) Eligible experimental and observational studies comparing methods of recruiting participants for RCTs were identified after a comprehensive search of Medline, Embase, the Cochrane Library and reference lists. Independent data extractions were completed by two reviewers who assessed the studies for eligibility and methodological quality. Outcome measures were consent rates, proportion enrolled by each method and cost of recruitment per participant. Summary estimators of effects were calculated using a random effects model and expressed as relative risk with 95% confidence intervals. Heterogeneity was analysed using the Q statistic. Paediatricians� attitudes to children�s participation in randomised controlled trials (focus group research) Qualitative analysis of focus group discussions involving 16 paediatricians and 5 trainees from a paediatric teaching hospital in Sydney was undertaken. Doctors varied in occupation, experience, research activity, age, gender, ethnicity and parenthood experience. A professional facilitator conducted the semi-structured group discussions. Recruitment ceased when informational redundancy was reached, after 4 focus groups involving 21 participants. The transcribed audiotapes were analysed by theme linkage using the constant comparative method. Australian paediatricians� and adult physicians� attitudes to randomised controlled trials (survey) A 44-item questionnaire was sent to 250 paediatricians and 250 adult physicians randomly selected from the membership list of the Royal Australasian College of Physicians. Questions assessing doctors� treatment philosophies and attitudes to trials were compared with demographic and practice variables. Parents� attitudes to children�s participation in randomised controlled trials (focus group research) Qualitative analysis of focus group discussions involving 33 parents from 5 different settings (representing parents of children with a life threatening, chronic or acute illness, with experience in trials and of healthy children) was undertaken. Parents varied in age, gender, ethnicity, level of education, research experience and their child�s health status. The transcribed discussions were analysed by theme linkage using the constant comparative method. Results Recruitment strategies used to encourage participation in randomised controlled trials (systematic review) Fifty papers were included (out of 8602 titles and abstracts searched) which described 8 RCTs, 2 quasi RCTs, 13 prospective cohort studies, 30 retrospective cohort studies and 2 before-after studies. These studies assessed how over 4 million people were approached for RCT participation using 87 different recruitment strategies, with 103,406 people enrolling in RCTs. Health care provider (HCP) referrals had the highest participant consent rates at the time of exposure to trial information (HCP referral versus target mailing: relative risk (RR) 1.84 (95% confidence interval (95%CI) 1.08, 3.13)). They also had the highest consent rates when potential participants respond to the recruitment material by further enquiry about the trial (HCP referral versus community presentation: RR 1.37 (1.06; 1.78); HCP referral versus worksite approach: RR 25.20 (20.19, 31.45); HCP referral versus general community approach: RR 2.53 (0.46, 14.05); HCP referral versus mailing: RR 3.29 (1.26, 8.60); HCP referral versus media: RR 2.66 (1.31, 5.41)). However, by the time potential participants attend eligibility assessment for trial participation, no difference in consent rates could be distinguished by method of recruitment. Higher proportions of study participants were recruited by methods that exposed larger numbers of potential candidates to trial information (despite their lower consent rates). The stated recruitment cost ranged from US$0 to $1108 per participant, with mailing being the most cost-effective method and community methods (such as community presentations, pamphlets and posters displayed at community sites) the least effective. Paediatricians� attitudes to children�s participation in randomised controlled trials (focus group research) From the focus group discussions, paediatricians thought parents balanced perceived gains and risks when deciding about trial participation. They also believed the child�s condition and parents� health beliefs and personal attributes influenced parents� decisions. Other factors thought to be important by paediatricians were the doctors� beliefs and their relationship with the investigators. Paediatricians perceived gains for trial participation including professional benefits for themselves, improved patient care, convenience for the families and themselves and scientific advancement. Perceived risks included inconvenience, inadequate resources and potential harms to the patient and the doctor-patient relationship. Paediatricians with previous research experience were most knowledgeable about RCTs and perceived greatest gains from trial participation. Paediatricians� personal treatment preferences hindered trial support. Australian paediatricians� and adult physicians� attitudes to randomised controlled trials (survey) Response rate from the paediatricians� and adult physicians� survey was 60% (300/500). Australian paediatricians and adult physicians are very similar in their treatment philosophies, and are clinician-oriented rather than research-oriented in their attitudes, with primary allegiance to their patients and preference for selecting treatment rather than referring for trial participation in the face of treatment uncertainty. Professional activities are clinically focused, with limited time assigned for research. Australian doctors perceive little reward for trial participation and claim that the opinions of referring doctors regarding RCTs does not influence them. Predictors of favourable attitudes to trial participation from the survey were time allocation for research, a history of referring patients to trials in the past and younger age (all p values less than 0.0001). Parents� attitudes to children�s participation in randomised controlled trials (focus group research) When parents were interviewed, they acknowledged balancing risks and benefits when deciding about trial participation for their child. Perceived benefits include the offer of hope, better care of their child, the opportunity to access new treatments, healthcare professionals and health information, meeting others in similar circumstances and helping others. Perceived risks include potential side effects, being randomised to ineffective treatments and the inconvenience of participation. The decision for trial participation is also influenced by parental factors (parents� knowledge, beliefs and emotional response), child factors (the child�s health status and preference about participation), trial factors (the use of placebos and the uncertainties of research) and doctor factors (doctor�s recommendations and communication of trial information). Conclusions There are many challenges to the successful conduct of RCTs. Ways of addressing these include: using effective methods of recruiting potential study participants (such as mailing of recruitment material to potential participants) and abandoning ineffective strategies (such as community methods): fostering greater willingness for trial participation by addressing parents� and paediatricians� concerns including enhancing communication between researchers, paediatricians and parents, and improving the gains-hazard balance (by increasing incentives while decreasing inconveniences); and reforming in the health care system to raise the priority placed on clinical research by restructuring clinical research in a clinically predominant workplace and with a clinically predominant workforce. The findings from this study have implications for researchers planning RCTs for children in the future. Careful consideration of the above will enhance RCTs participation for children improving efficiency, lowering costs and ultimately improving the future health care of children.

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Dakin, Helen A. "Economic evaluation of factorial randomised controlled trials." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:77eda1f6-dd8c-439a-8871-75fd57a4c7f5.

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Factorial randomised controlled trials (RCTs) evaluate two or more interventions simultaneously, enabling assessment of interactions between treatments. This thesis presents literature reviews, methodological reviews, simulation studies and applied case studies that explore methods for assessing cost-effectiveness based on factorial RCTs. My systematic review suggests that factorial RCTs account for around 3% of trial-based economic evaluations, although there is currently no guidance or methodological work indicating the most appropriate methods. Around 40% of published studies assumed no interaction between treatments and many were poorly-reported. Various mechanisms are likely to produce large interactions within economic endpoints such as costs, quality-adjusted life-years (QALYs) and net benefits. Failing to take account of interactions can introduce bias and prevent efficient allocation of healthcare resources. I developed the opportunity cost of ignoring interactions as a measure of the implications of this bias. However, allowing for small, chance interactions is inefficient, potentially leading to over-investment in research if trial-based evaluations are used to inform decisions about subsequent research. Nonetheless, analyses on simulated trial data suggest that the opportunity cost of adopting a treatment that will not maximise health gains from the healthcare budget is minimised by including all interactions regardless of magnitude or statistical significance. Different approaches for conducting economic evaluations of factorial RCTs (including regression techniques, extrapolation using patient-level simulation, and considering different components of net benefit separately) are evaluated within three applied studies, including both full and partial factorials with 2x2 and 2x2x2 designs. I demonstrate that within both trial-based and model-based economic evaluation, efficient allocation of healthcare resources requires consideration of interactions between treatments, and joint decisions about interacting treatments based on incremental cost-effectiveness evaluated “inside-the-table” on a natural scale. I make recommendations for the design, analysis and reporting of factorial trial-based economic evaluations based on the results of this thesis.

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Kaur, Geetinder. "Recruitment to randomised controlled trials with children." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3002903/.

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Recruitment to randomised controlled trials is known to be difficult. Poor recruitment has several adverse consequences. It affects the validity of study findings, is a common cause of trial extensions and may result in premature termination of trials, which is a huge loss in terms of invested funds, resources and lost knowledge. Non-completion or delayed completion of studies maintains the uncertainty about the efficacy and safety of interventions, thereby delaying or preventing the use of effective interventions and prolonging the use of ineffective or potentially harmful treatments. Recruitment of children to randomised controlled trials is thought to be more challenging due to the vulnerability of the population and the fact that consent is provided by another person usually parents. This thesis aims to review the recruitment performance, i.e. comparison of achieved to anticipated recruitment, of randomised controlled trials with children and identify the factors associated with good or poor recruitment. We undertook a pilot systematic review of recruitment and retention in randomised controlled trials with children, in published literature, and found that few studies report recruitment information but those that do, report very high rates of percentage total recruitment achieved (%TR) and consent. It was not possible to obtain unbiased estimates of recruitment performance and consent rate due to the likelihood of selective reporting and/or non-publication of trials with unsuccessful recruitment. We subsequently conducted a review of recruitment of children to randomised controlled trials in the National Institute of Health Research (NIHR) Clinical Research Network (CRN) portfolio and found that under-recruitment and delayed recruitment are common problems in paediatric trials. Having a trial manager or coordinator was found to be significantly associated with successful recruitment. Other factors such as being an IMP (Investigational Medicinal Product) vs. non-IMP trial, trial of acute vs. chronic illness, having CTU (Clinical Trials Unit) involvement, pilot/feasibility study and additional trial demands had no statistically significant association with recruitment success. Since recruitment to a clinical trial can be affected by a number of internal and external factors, we conducted a survey with the clinical teams of a multi-centre randomised controlled trial with children, the MAGNETIC trial, to understand the various facilitators and barriers to recruitment. In order to identify the facilitators and barriers to recruitment and establish the recruitment experience of clinical teams in a systematic manner, we developed an evidence based recruitment survey tool. The survey tool is an online questionnaire that presents a comprehensive evidence based list of facilitators and barriers and free text space for responders to record the strategies applied to overcome these barriers and suggestions for change in organisation of trials to boost recruitment. The survey of clinical teams recruiting to the MAGNETIC trial found that a motivated clinical team with effective communication skills, effective coordination between study team members at site and between sites and CTU, trial management support, research experience of PI, presence of a research nurse and availability of a designated research team were imperative for trial recruitment success. Heavy clinical workload, shift patterns of work, lack of trained staff particularly out of hours, GCP training, local clinical arrangements and parental anxiety about the safety of experimental treatment were recognised as important barriers to recruitment. A trial specific barrier was difficulty faced by the clinicians in seeking consent from the parents of an acutely ill child in the emergency setting and suggestions were made for consideration of deferred consent. We concluded that recruitment to randomised controlled trials with children is challenging and poor recruitment and recruitment delays are a common problem. Reporting of recruitment and consent in paediatric trials is poor and needs improvement. Presence of a dedicated trial manager is significantly associated with successful recruitment and the various generic and trial specific facilitators and barriers to recruitment that have been identified can be used by trialists in planning and conducting future clinical trials with children.

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Coskinas, Xanthi. "Changes to design aspects of ongoing randomised controlled trials." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29452.

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Unplanned changes to the research plan of a randomised controlled trial (RCT) may be a necessary response to unforeseen circumstances. Such changes can help ensure the value and relevance of a trial, but also have the potential to introduce a bias if performed inappropriately. This thesis addresses three broad aims. The first was to highlight the methodological implications of approaches to making various unplanned changes through a series of simulation studies. The second was to estimate the prevalence of such changes to a contemporary sample of published RCTs registered with the Australian New Zealand Clinical Trial Registry (ANZCTR). The third was to assess, and extend as applicable, recommendations for ensuring such changes are performed appropriately and are well documented. The simulation studies were performed using data from a large RCT of statin therapy for secondary prevention. The first of these demonstrated how unplanned changes (to various aspects of the design such as the primary endpoint) risks introducing a bias if undertaken with knowledge of treatment allocation, but not if made without knowledge of treatment allocation. The second investigated strategies for reacting to an observed imbalance on baseline prognostic factors in an RCT. It demonstrated that: continuing with original plans of unadjusted analyses, provided valid p-values irrespective of the direction of the prognostic imbalance, and any decisions informed by knowledge of the direction of the prognostic covariate imbalance were prone to bias. The third simulation study investigated strategies for reacting to a lower-than-expected event rate. It showed that switching to an expanded composite endpoint in response to a low pooled event rate does not inflate the type 1 error rate (and is likely to improve the statistical power, provided the expanded composite is sound). A sample of 181 RCTs that were registered with the ANZCTR and had published a primary result paper were assessed for changes to their research plans, and whether these changes were legitimate or not (that is, made with or without knowledge of treatment allocation). A full audit was conducted on trials with accessible protocols (N=124) and a limited central review on trials without accessible protocols (N=57). The primary results publication was cross-checked with the protocol documents across six methodological aspects for the full audit, and trialists were contacted to resolve queries as necessary. The publication was checked against the registry record for the limited central review, over a subset of three methodological aspects. A key finding of this study was that it was often not possible to reliably assess whether changes had been made or whether changes were made in a blinded manner, based on review of documentation alone. After clarification was sought from the participating trialists, changes were found to be relatively common but typically made in a blinded manner. Improvements to the way unplanned changes to RCT research plans are documented are needed. A set of recommendations to supplement existing guidelines relating to the documentation of RCT research plans was developed. One key recommendation was that trialists should adopt and implement the principles of the recently developed CONSERVE 2021 Statement to appropriately perform and document substantive changes. A second was that strategies that oblige trialists to upload full protocols (and protocol amendments) to clinical trial registries warrant further investigation and further consideration should be given to including all key methodological aspects in registry records. The work undertaken provides valuable guidance for trialists (and stakeholders) on how to make and document a methodologically justifiable change to a planned RCT design/analysis and highlights the circumstances under which a change can lead to bias. This is important for ensuring that methodically unsound changes to RCTs are recognised and avoided, and that RCTs that have undergone methodically sound changes are not incorrectly dismissed as potentially biased.

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Carragher, Raymond. "Detection of safety signals in randomised controlled trials." Thesis, University of Strathclyde, 2017. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=29239.

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The occurrence, severity, and duration of patient adverse events are routinely recorded during randomised clinical trials. This data is used by a trial's Data Monitoring Committee to make decisions regarding the safety of a treatment and may lead to the alteration or discontinuation of a trial if real safety issues are detected. There are many different types of adverse event and the statistical analysis of this data, particularly with regard to hypothesis testing, must take into account potential multiple comparison issues. Unadjusted hypothesis tests may lead to large numbers of false positive results, but simple adjustments are generally too conservative. In addition, the anticipated effect sizes of adverse events in clinical trials are generally small and consequently the power to detect such effects is low. A number of recent classical and Bayesian methods, which use groupings of adverse events, have been proposed to address this problem. We illustrate and compare a number of these approaches, and investigate if their use of a common underlying model, which involves groupings of adverse events by body-system or System Organ Class, is useful in detecting adverse events associated with treatments. For data where this type of grouped approach is appropriate, the methods considered are shown to correctly flag more adverse event effects than standard approaches, while maintaining control of the overall error rate. While controlling for multiple types of adverse event, these proposed methods do not take into account event timings or patient exposure time, and are more suited to end of trial analysis. In order to address the desire for the early detection of safety issues in clinical trials a number of Bayesian methods are introduced to analyse the accumulation of adverse events as the trial progresses, taking into account event timing, patient time in study, and body-system. These methods are suitable for use at interim trial safety analyses. The models which performed best were those that had a common body-system dependence over the duration of the trial.

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Schulz, Kenneth Fredrick. "Methodological quality and bias in randomised controlled trials." Thesis, London School of Hygiene and Tropical Medicine (University of London), 1994. http://researchonline.lshtm.ac.uk/4646508/.

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To evaluate the methodological quality of randomised trials in recently published articles and to examine the associations between methodological quality and bias, three related investigations were undertaken. First, to ensure the development of useful measures for the adequacy of randomisation, approaches to allocation were assessed as reported in 206 parallel group trials published in recent volumes of journals of obstetrics and gynaecology. Next, a study was conducted of associations between methodological quality and treatment effects. The material analysed came from 250 trials in 33 meta-analyses on pregnancy and childbirth topics. Finally, the reported approaches to blinding and handling of exclusions were assessed from a random sample of 110 of the 206 previously identified reports. In the 206 published trials, 77% reported either inadequately or unclearly concealed treatment allocation. Additional analyses suggest that non-random manipulation of comparison groups may have occurred. In the next study. compared with trials in which authors reported adequately concealed treatment allocation, trials in which authors reported inadequately or unclearly concealed allocation yielded larger estimates of treatment effects (p < 0.001). Odds ratios were distorted by 41% and 33%, respectively. Those associations likely represent bias and are particularly disconcerting in light of the results above from recently published trials. Lack of double-blinding in trials was also associated with larger treatment benefits. However, trials in which authors reported excluding 2 participants after randomisation were not associated with larger treatment effects. That lack of association appeared to be due to incomplete reporting. 3 The analysis of 110 recently published trials also supported the findings that some of the trials not reporting exclusions may actually have had exclusions. In practice, that incomplete reporting could lead to misinterpretations of trial quality. Moreover, only about half the trials that could have double-blinded actually did so. When investigators attempted double-blinding, only 16% provided any written assurances of successfully implementing blinding and only 6% tested its efficacy.

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McCann, Sharon Katrina. "Patients' perspectives on participation in randomised controlled trials." Thesis, University of Aberdeen, 2007. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU494624.

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The study had three components: (i) an overview of the literature on participant involvement in RCTs; (ii) a meta-ethnography focusing on factors impacting on participant recruitment to RCTs; and (iii) an embedded qualitative study investigating recruitment and participation in an ongoing UK multicentre trial. Non participant observation of trial recruitment consultations and in-depth interviews were conducted with patients invited to participate in the trial from two recruitment sites. Decisions about trial participation took part in a broad personal context, such as perceptions of treatment, levels of symptoms control, and prior experience of interventions. Views about the trial procedures, treatment interventions, and impressions of recruiting staff were also found to be salient. Although altruism was identified as a factor impacting on trial participation, this tended to be ‘conditional altruism’, dependent on expectations of personally benefiting from participating in a trial. Perceptions of benefiting personally from a trial were linked to the trial intervention(s) and also towards the trial process. Despite agreeing to be randomised it was apparent that some patients harboured a ‘preference’ for a treatment. However, people subsequently seemed able to adjust to their allocated treatment, although there were misconceptions about how treatment decisions had been reached. Perceptions of trial involvement, and having directly benefited from trial participation seemed particularly dependent on which treatment people were allocated to. Crucially, the findings have emphasised that trials are not simply an experimental tool operating in a vacuum, independent of the view and experiences of participants; and offer rich insights, which are likely to benefit people recruiting in future trials, and for future trial participants.

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Dodd, Susanna. "Modelling departure from randomised treatment in randomised controlled trials with survival outcomes." Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2006887/.

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Randomised controlled trials are considered the gold standard study design, as random treatment assignment provides balance in prognosis between treatment arms and protects against selection bias. When trials are subject to departures from randomised treatment, however, simple but naïve statistical methods that purport to estimate treatment efficacy, such as per protocol or as treated analyses, fail to respect this randomisation balance and typically introduce selection bias. This bias occurs because departure from randomised treatment is often clinically indicated, resulting in systematic differences between patients who do and do not adhere to their assigned intervention. There exist more appropriate statistical methods to adjust for departure from randomised treatment but, as demonstrated by a review of published trials, these are rarely employed, primarily due to their complexity and unfamiliarity. The focus of this research has been to explore, explain, demonstrate and compare the use of causal methodologies in the analysis of trials, in order to increase the accessibility and comprehensibility by non-specialist analysts of the available, but somewhat technical, statistical methods to adjust for treatment deviations. An overview of such methods is presented, intended as an aid to researchers new to the field of causal inference, with an emphasis on practical considerations necessary to ensure appropriate implementation of techniques, and complemented by a number of guidance tools summarising the necessary clinical and statistical considerations when carrying out such analyses. Practical demonstrations of causal analysis techniques are then presented, with existing methods extended and adapted to allow for complexities arising from the trial scenarios. A particular application from epilepsy demonstrates the impact of various statistical factors when adjusting for skewed time-varying confounders and different reasons for treatment changes on a complicated time to event outcome, including choice of model (pooled logistic regression versus Cox models for inverse probability of censoring weighting methods, compared with a rank-preserving structural failure time model), time interval (for creating panel data for time-varying confounders and outcome), confidence interval estimation method (standard versus bootstrapped) and the considerations regarding use of spline variables to estimate underlying risk in pooled logistic regression. In this example, the structural failure time model is severely limited by its restriction on the types of treatment changes that can be adjusted for; as such, the majority of treatment changes are necessarily censored, introducing bias similar to that in a per protocol analysis. With inverse probability weighting adjustment, as more treatment changes and confounders are accounted for, treatment effects are observed to move further away from the null. Generally, Cox models seemed to be more susceptible to changes in modelling factors (confidence interval estimation, time interval and confounder adjustment) and displayed greater fluctuations in treatment effect than corresponding pooled logistic regression models. This apparent greater stability of logistic regression, even when subject to severe overfitting, represents a major advantage over Cox modelling in this context, countering the inherent complications relating to the fitting of spline variables. This novel application of complex methods in a complicated trial scenario provides a useful example for discussion of typical analysis issues and limitations, as it addresses challenges that are likely to be common in trials featuring problems with nonadherence. Recommendations are provided for analysts when considering which of these analysis methods should be applied in a given trial setting.

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Whitehead, Amy. "Sample size justifications for pilot trials of publicly funded randomised controlled trials." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/15822/.

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A sample size estimate for a clinical trial is an important issue as incorrectly estimating it could have both ethical and financial implications for the trial. Calculating the required sample size for a trial with a continuous outcome requires an estimate of the population variance. A pilot trial can be used to get an estimate of the population variance. However, pilot trials are often small and may give imprecise estimates; adjustment methods are discussed which allow for this imprecision. Theoretical minimum values for the overall trial sample size when using an adjustment method to design the main trial after an external pilot trial are provided. Using the results recommendations for external pilot trial sample size are presented which aim to minimise the overall trial sample size. It was found that the optimal pilot trial sample size increases with the size of the main trial, therefore stepped rules of thumb are proposed. For a 90% powered main trial this method indicates that the sample size for a two-armed pilot trial to minimise the overall sample size should be 150, 50, 30 and 20 for standardised effect sizes (δ) of δ < 0.1, 0.1 ≤ δ < 0.3, 0.3 ≤ δ < 0.7 and δ ≥ 0.7 respectively. The work is extended to allow for unequal cost per patient between the two trials. The results show that when the pilot trial is less expensive per patient than the main trial the optimal pilot trial sample size increases, giving more precision for the variance estimate and a relatively small main trial. The opposite is true when the main trial is less expensive than the pilot trial. For a 90% powered main trial this method indicates that the sample size for a two-armed pilot trial to minimise the overall sample size should be between 40- 260, 20-80, 20-40 and 20-30 dependent on the relative cost of the pilot and main trial per participant for standardised effect sizes (δ) of δ < 0.1, 0.1 ≤ δ < 0.3, 0.3 ≤ δ < 0.7 and δ ≥ 0.7 respectively. For internal pilot trials it is shown that the restricted sample size recalculation procedure raises the average sample size and power of the main trial. Aiming to minimise the overall trial sample size, it was found that the optimal pilot trial sample size rises as the main trial size increases. The work presented aims to help researchers choose sample sizes for pilot trials and to assess the impact selected methods have on the power and required sample size of the subsequent main trial.

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Books on the topic "Randomised controlled trials"

1

Randomised controlled clinical trials. 2nd ed. Boston: Kluwer Academic Publishers, 1996.

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Bulpitt, Christopher J. Randomised Controlled Clinical Trials. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-6347-1.

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J, Hayes Richard, and Hayes Richard J. Cluster randomised trials. Boca Raton: Taylor & Francis, 2009.

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Song, F. Antimicrobial prophylaxis in colorectal surgery: A systematic review of randomised controlled trials. Alton: Core Research, on behalf of the NCCHTA, 1998.

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Eldridge, Sandra. A practical guide to cluster randomised trials in health services research. Chichester, West Sussex: John Wiley & Sons, 2011.

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Campbell, Michael J. How to design, analyse and report cluster randomised trials in medicine and health related research. Chichester, West Sussex: John Wiley & Sons, 2014.

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Torgerson, David J. Designing and running randomised trials in health, education, and the social sciences. New York: Palgrave Macmillan, 2008.

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Jadad, Alejandro R., and Murray W. Enkin, eds. Randomized Controlled Trials. Oxford, UK: Blackwell Publishing Ltd, 2007. http://dx.doi.org/10.1002/9780470691922.

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Introduction to randomized controlled clinical trials. 2nd ed. Boca Raton, FL: Chapman & Hall/CRC, 2006.

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Horsfall, Tessa Ann. What is the evidence to suggest that early supported discharge for patients following a stroke is a feasible alternative to usual care and rehabilitation of randomised controlled trials. Oxford: Oxford Brookes University, 2003.

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Book chapters on the topic "Randomised controlled trials"

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Stewart, Antony. "Randomised controlled trials." In Basic Statistics and Epidemiology, 125–27. 5th ed. London: CRC Press, 2022. http://dx.doi.org/10.1201/9781003148111-31.

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Abdulla, Adam. "Randomised controlled trials." In Coaching Students in Secondary Schools, 177–88. Abingdon, Oxon ; New York, NY : Routledge, 2018.: Routledge, 2017. http://dx.doi.org/10.4324/9781315113494-19.

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Bulpitt, Christopher J. "Stopping Rules For Trials." In Randomised Controlled Clinical Trials, 233–43. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-6347-1_12.

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O’Flynn, Kieran. "Randomised Controlled Trials (RCTs)." In Imaging and Technology in Urology, 357–60. London: Springer London, 2012. http://dx.doi.org/10.1007/978-1-4471-2422-1_79.

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Torgerson, David J., and Carole J. Torgerson. "Factorial Randomised Controlled Trials." In Designing Randomised Trials in Health, Education and the Social Sciences, 114–18. London: Palgrave Macmillan UK, 2008. http://dx.doi.org/10.1057/9780230583993_11.

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Torgerson, David J., and Carole J. Torgerson. "Pilot Randomised Controlled Trials." In Designing Randomised Trials in Health, Education and the Social Sciences, 119–26. London: Palgrave Macmillan UK, 2008. http://dx.doi.org/10.1057/9780230583993_12.

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Torgerson, David J., and Carole J. Torgerson. "Cluster Randomised Controlled Trials." In Designing Randomised Trials in Health, Education and the Social Sciences, 99–107. London: Palgrave Macmillan UK, 2008. http://dx.doi.org/10.1057/9780230583993_9.

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Bulpitt, Christopher J. "Introduction." In Randomised Controlled Clinical Trials, 1–6. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-6347-1_1.

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Bulpitt, Christopher J. "Information to be Collected During a Trial." In Randomised Controlled Clinical Trials, 183–98. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-6347-1_10.

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Bulpitt, Christopher J. "The Conduct of the Trial — Good Clinical Practice." In Randomised Controlled Clinical Trials, 199–231. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4615-6347-1_11.

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Conference papers on the topic "Randomised controlled trials"

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Relton, Clare. "Randomised Controlled Trials." In HRI London 2019—Cutting Edge Research in Homeopathy: Presentation Abstracts. The Faculty of Homeopathy, 2020. http://dx.doi.org/10.1055/s-0040-1702078.

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Hanlon, Peter, Sofia Dias, David McAllister, Sarah Wild, Frances Mair, Bruce Guthrie, Elaine Butterly, Nicky Welton, and Laurie Hannigan. "Assessing Representativeness of Randomised Controlled Trials using Serious Adverse Events." In NAPCRG 50th Annual Meeting — Abstracts of Completed Research 2022. American Academy of Family Physicians, 2023. http://dx.doi.org/10.1370/afm.21.s1.3730.

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Churches, Richard, Steve Higgins, and Robin Hall. "THE POTENTIAL OF TEACHER-LED RANDOMISED CONTROLLED TRIALS IN EDUCATION RESEARCH." In 10th annual International Conference of Education, Research and Innovation. IATED, 2017. http://dx.doi.org/10.21125/iceri.2017.0176.

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Haseeb, F., A. Mathioudakis, M. Fally, J. Vestbo, P. Dark, A. Bentley, and T. Felton. "P190 Systematic survey of reported outcomes in ventilator associated pneumonia randomised controlled trials." In British Thoracic Society Winter Meeting, Wednesday 17 to Friday 19 February 2021, Programme and Abstracts. BMJ Publishing Group Ltd and British Thoracic Society, 2021. http://dx.doi.org/10.1136/thorax-2020-btsabstracts.335.

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Birch, Jack, Rebecca Jones, Julia Mueller, Matthew McDonald, Rebecca Richards, Michael Kelly, Simon Griffin, and Amy Ahern. "A systematic review of inequalities in the uptake of, adherence to and effectiveness of behavioural weight management interventions." In Building Bridges in Medical Science 2021. Cambridge Medicine Journal, 2021. http://dx.doi.org/10.7244/cmj.2021.03.001.1.

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Background: It has been suggested that interventions focusing on individual behaviour change, such as behavioural weight management interventions, may exacerbate health inequalities. These intervention-generated inequalities may occur at different stages, including intervention uptake, adherence and effectiveness. We conducted a systematic review to synthesise evidence on how different measures of inequality moderate the uptake of, adherence to and effectiveness of behavioural weight management interventions in adults. Methods: We updated a previous systematic literature review from the US Preventive Services Taskforce to identify trials of behavioural weight management interventions in adults that could be conducted in or recruited from primary care. Medline, Cochrane database (CENTRAL) and PsycINFO were searched. Only randomised controlled trials and cluster-randomised controlled trials were included. Two investigators independently screened articles for eligibility and conducted risk of bias assessment. We curated publication families for eligible trials. The PROGRESS-Plus acronym (place of residence, race/ethnicity, occupation, gender, religion, education, socioeconomic status, social capital, plus other discriminating factors) was used to consider a comprehensive range of health inequalities. Data on trial uptake, intervention adherence, weight change, and PROGRESS-Plus related-data were extracted. Results: Data extraction in currently underway. A total of 108 studies are included in the review. Data will be synthesised narratively and through the use of Harvest Plots. A Harvest plot for each PROGRESS-Plus criterion will be presented, showing whether each trial found a negative, positive or no health inequality gradient. We will also identify potential sources of unpublished original research data on these factors which can be synthesised through a future individual participant data meta- analysis. Conclusions and implications: The review findings will contribute towards the consideration of intervention-generated inequalities by researchers, policy makers and healthcare and public health practitioners. Authors of trials included in the completed systematic review may be invited to collaborate on a future IPD meta-analysis. PROSPERO registration number: CRD42020173242

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Brightling, Christopher E., Mina Gaga, Hiromasa Inoue, Jing Li, Jorge Maspero, Sally Wenzel, Somopriyo Maitra, et al. "Late Breaking Abstract - LUSTER-1 and -2: randomised controlled trials of fevipiprant in severe asthma." In ERS International Congress 2020 abstracts. European Respiratory Society, 2020. http://dx.doi.org/10.1183/13993003.congress-2020.4614.

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Speich, Benjamin, Viktoria Gloy, Nadine Schur, Lars G. Hemkens, Matthias Schwenkglenks, and Matthias Briel. "32 Open access budget tools for the planning of randomised controlled trials: a scoping review." In EBM Live Abstracts, July 2019, Oxford, UK. BMJ Publishing Group Ltd, 2019. http://dx.doi.org/10.1136/bmjebm-2019-ebmlive.40.

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Thiel, Sira, Sarah R. Haile, Mirko Peitzsch, Esther I. Schwarz, Noriane A. Sievi, Salome Kurth, Felix Beuschlein, Malcolm Kohler, and Thomas Gaisl. "Endocrine responses during CPAP-withdrawal in obstructive sleep apnea: data from two randomised controlled trials." In ERS International Congress 2019 abstracts. European Respiratory Society, 2019. http://dx.doi.org/10.1183/13993003.congress-2019.pa1996.

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Freije, F., and U. Hedegaard. "4CPS-078 Motivational interviewing in clinical pharmacist interventions: a systematic review of randomised controlled trials." In 26th EAHP Congress, Hospital pharmacists – changing roles in a changing world, 23–25 March 2022. British Medical Journal Publishing Group, 2022. http://dx.doi.org/10.1136/ejhpharm-2022-eahp.112.

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Ng, D., J. Klassen, ND Embleton, and W. McGuire. "G486(P) Protein hydrolysate versus standard formula for preterm infants: Systematic review of randomised controlled trials." In Royal College of Paediatrics and Child Health, Abstracts of the Annual Conference, 24–26 May 2017, ICC, Birmingham. BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health, 2017. http://dx.doi.org/10.1136/archdischild-2017-313087.478.

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Reports on the topic "Randomised controlled trials"

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Masset, Edoardo. Combining economic modelling and randomised controlled trials: An unexploited synergyCombining economic modelling and randomised controlled trials: An unexploited synergy. Edited by Radhika Menon. Centre of Excellence for Development Impact and Learning (CEDIL), 2021. http://dx.doi.org/10.51744/cmb3.

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Over the last decade, many researchers have conducted randomised trials alongside economic models. The work of these researchers has shown that both approaches are strengthened by their combined use and the conclusions they lead to are full of policy implications. In the latest CEDIL Methods Brief, Edoardo Masset, Research Director, CEDIL Programme, uses three examples to offer tips on the application of modelling to evaluate development interventions and explore various policy questions. The brief shows that models and experiments should be seen as complementary, rather than as alternative approaches. This brief is based on the CEDIL Inception Paper No. 9, Structural Modelling in Policy Making, by Orazio Attanasio and Debbie Blair. This paper is available on the CEDIL website.

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Landon, Tess, and Harald Hochreiter. Randomised controlled trials and other experimental approaches in the Austrian Research Promotion Agency. Fteval - Austrian Platform for Research and Technology Policy Evaluation, April 2022. http://dx.doi.org/10.22163/fteval.2022.554.

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The objective of this paper/presentation is to highlight how experimental approaches, specifically Randomised Controlled Trials (RCTs), can be leveraged to evaluate and measure the impact of new programmes, support programme development and test new services in funding and innovation agencies. RCTs are seen in many facets of public policy, however RCTs as a method for innovation agencies to evaluate new initiatives is relatively new. We present three RCTs implemented in the Austrian Research Promotion Agency (FFG) that have received funding from the European Union’s Horizon 2020 research and innovation programme. The trials are implemented to evaluate the effectiveness of new measures intended to help strengthen R&I in start-ups and SMEs. Through these three examples, we aim to demonstrate the advantages in which RCTs can augment the evaluation of new services as well as challenges that come with implementing RCTs. For one RCT, we will present final results. Two RCTs are ongoing, and we will present the trial design. We also discuss the operational aspects of incorporating experimentation in an innovation agency.

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Chen, Peng, Hanbing Chen, Kang Li, Jun Shao, Qi-Hong Chen, and Rui-Qiang Zheng. Application of vitamin C in adult patients with sepsis: a meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review Protocols, April 2020. http://dx.doi.org/10.37766/inplasy2020.4.0186.

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Zhong, Lingyuan, JL Wang, Y. Bo, N. Luo, and PS Hao. Pharmaceutical preparations of periplaneta Americana for Skin Ulcer：a protocol for a meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, May 2022. http://dx.doi.org/10.37766/inplasy2022.5.0131.

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Cheng, Lu, Xiaolin Li, Shuqi Mi, Xudong Zhang, Wei Guo, Yi Ying, and Jiping Zhao. Should acupuncture therapy be used for acute facial paralysis：a systematic review and meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, October 2020. http://dx.doi.org/10.37766/inplasy2020.10.0004.

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Yagiz, Gokhan, Esedullah Akaras, Hans-Peter Kubis, and Julian Andrew Owen. Effects of Exercise on Skeletal Muscle Architecture in Healthy Adults: A systematic review of randomised controlled trials (protocol). INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, May 2020. http://dx.doi.org/10.37766/inplasy2020.5.0074.

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Alsina-Restoy, Xavier, Rodrigo Torres-Castro, Estrella Caballeria, Lilian Solis-Navarro, Joel Francesqui, Elena Gimeno-Santos, Fernanda Hernández, Isabel Blanco, and Jacobo Sellarés. Effects of pulmonary rehabilitation on patients with sarcoidosis: a systematic review and meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, March 2022. http://dx.doi.org/10.37766/inplasy2022.3.0046.

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Review question / Objective: Is pulmonary rehabilitation an effective intervention in patients with sarcoidosis? Condition being studied: Sarcoidosis. Eligibility criteria: We will include studies published until March 2022. The population studied must be adults (>18y) with diagnosis of sarcoidosis that performed a structured program of pulmonary rehabilitation. We will include only outpatients. They must be patients with stable disease and without exacerbation for at least one month.

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Wang, Jiali, Lingyuan Zhong, Yang Bo, Nan Luo, and Pingsheng Hao. Pharmaceutical preparations of periplaneta Americana for Pressure ulcer: a protocol for a meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, July 2022. http://dx.doi.org/10.37766/inplasy2022.7.0082.

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Chen, X. A new therapy for chronic heart failure for using acupuncture: a systematic review and meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review Protocols, April 2020. http://dx.doi.org/10.37766/inplasy2020.4.0005.

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Huang, Hui-Bin, Jun-Ping Qin, Yuan Xu, and Bin Du. Aerosolized antibiotics for the treatment of pneumonia in mechanically ventilated patients: a systematic review and meta-analysis of randomised controlled trials. INPLASY - International Platform of Registered Systematic Review and Meta-analysis Protocols, July 2020. http://dx.doi.org/10.37766/inplasy2020.7.0039.

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