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"Randomized trial"
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Machine learning reduced workload with minimal risk of missing studies: development and evaluation of a randomized controlled trial classifier for Cochrane Reviews
by
Marshall, Iain J.
,
Elliott, Julian
,
Mavergames, Chris
in
Algorithms
,
Automation
,
Bibliographic data bases
2021
This study developed, calibrated, and evaluated a machine learning classifier designed to reduce study identification workload in Cochrane for producing systematic reviews.
A machine learning classifier for retrieving randomized controlled trials (RCTs) was developed (the “Cochrane RCT Classifier”), with the algorithm trained using a data set of title–abstract records from Embase, manually labeled by the Cochrane Crowd. The classifier was then calibrated using a further data set of similar records manually labeled by the Clinical Hedges team, aiming for 99% recall. Finally, the recall of the calibrated classifier was evaluated using records of RCTs included in Cochrane Reviews that had abstracts of sufficient length to allow machine classification.
The Cochrane RCT Classifier was trained using 280,620 records (20,454 of which reported RCTs). A classification threshold was set using 49,025 calibration records (1,587 of which reported RCTs), and our bootstrap validation found the classifier had recall of 0.99 (95% confidence interval 0.98–0.99) and precision of 0.08 (95% confidence interval 0.06–0.12) in this data set. The final, calibrated RCT classifier correctly retrieved 43,783 (99.5%) of 44,007 RCTs included in Cochrane Reviews but missed 224 (0.5%). Older records were more likely to be missed than those more recently published.
The Cochrane RCT Classifier can reduce manual study identification workload for Cochrane Reviews, with a very low and acceptable risk of missing eligible RCTs. This classifier now forms part of the Evidence Pipeline, an integrated workflow deployed within Cochrane to help improve the efficiency of the study identification processes that support systematic review production.
•Systematic review processes need to become more efficient.•Machine learning is sufficiently mature for real-world use.•A machine learning classifier was built using data from Cochrane Crowd.•It was calibrated to achieve very high recall.•It is now live and in use in Cochrane review production systems.
Journal Article
A meta-epidemiological analysis of post-hoc comparisons and primary endpoint interpretability among randomized noncomparative trials in clinical medicine
by
Msaouel, Pavlos
,
Ludmir, Ethan B.
,
Sherry, Alexander D.
in
Clinical medicine
,
Clinical trials
,
Data Interpretation, Statistical
2024
Randomized noncomparative trials (RNCTs) promise reduced accrual requirements vs randomized controlled comparative trials because RNCTs do not enroll a control group and instead compare outcomes to historical controls or prespecified estimates. We hypothesized that RNCTs often suffer from two methodological concerns: (1) lack of interpretability due to group-specific inferences in nonrandomly selected samples and (2) misinterpretation due to unlicensed between-group comparisons lacking prespecification. The purpose of this study was to characterize RNCTs and the incidence of these two methodological concerns.
We queried PubMed and Web of Science on September 14, 2023, to conduct a meta-epidemiological analysis of published RNCTs in any field of medicine. Trial characteristics and the incidence of methodological concerns were manually recorded.
We identified 70 RNCTs published from 2002 to 2023. RNCTs have been increasingly published over time (slope = 0.28, 95% CI 0.17–0.39, P < .001). Sixty trials (60/70, 86%) had a lack of interpretability for the primary endpoint due to group-specific inferences. Unlicensed between-group comparisons were present in 36 trials (36/70, 51%), including in the primary conclusion of 31 trials (31/70, 44%), and were accompanied by significance testing in 20 trials (20/70, 29%). Only five (5/70, 7%) trials were found to have neither of these flaws.
Although RNCTs are increasingly published over time, the primary analysis of nearly all published RNCTs in the medical literature was unsupported by their fundamental underlying methodological assumptions. RNCTs promise group-specific inference, which they are unable to deliver, and undermine the primary advantage of randomization, which is comparative inference. The ongoing use of the RNCT design in lieu of a traditional randomized controlled comparative trial should therefore be reconsidered.
Journal Article
Aerobic endurance training to improve cognition and enhance recovery in schizophrenia: design and methodology of a multicenter randomized controlled trial
by
Meyer-Lindenberg, Andreas
,
Schneider-Axmann, Thomas
,
Lembeck Moritz
in
Cardiovascular diseases
,
Clinical trials
,
Cognition & reasoning
2021
Even today, patients with schizophrenia often have an unfavorable outcome. Negative symptoms and cognitive deficits are common features in many patients and prevent recovery. In recent years, aerobic endurance training has emerged as a therapeutic approach with positive effects on several domains of patients’ health. However, appropriately sized, multicenter randomized controlled trials that would allow better generalization of results are lacking. The exercise study presented here is a multicenter, rater-blind, two-armed, parallel-group randomized clinical trial in patients with clinically stable schizophrenia being conducted at five German tertiary hospitals. The intervention group performs aerobic endurance training on bicycle ergometers three times per week for 40–50 min/session (depending on the intervention week) for a total of 26 weeks, and the control group performs balance and tone training for the same amount of time. Participants are subsequently followed up for 26 weeks. The primary endpoint is all-cause discontinuation; secondary endpoints include psychopathology, cognition, daily functioning, cardiovascular risk factors, and explorative biological measures regarding the underlying mechanisms of exercise. A total of 180 patients will be randomized. With currently 162 randomized participants, our study is the largest trial to date to investigate endurance training in patients with schizophrenia. We hypothesize that aerobic endurance training has beneficial effects on patients’ mental and physical health, leading to lower treatment discontinuation rates and improving disease outcomes. The study results will provide a basis for recommending exercise interventions as an add-on therapy in patients with schizophrenia.The study is registered in the International Clinical Trials Database (ClinicalTrials.gov identifier [NCT number]: NCT03466112) and in the German Clinical Trials Register (DRKS-ID: DRKS00009804).
Journal Article
Assessing the Gold Standard — Lessons from the History of RCTs
by
Greene, Jeremy A
,
Podolsky, Scott H
,
Jones, David S
in
Clinical trials
,
Disease
,
Drug Approval - history
2016
Over the past 70 years, randomized, controlled trials (RCTs) have reshaped medical knowledge and practice. Popularized by mid-20th-century clinical researchers and statisticians aiming to reduce bias and enhance the accuracy of clinical experimentation, RCTs have often functioned well in that role. Yet the past seven decades also bear witness to many limitations of this new “gold standard.” The scientific and political history of RCTs offers lessons regarding the complexity of medicine and disease and the economic and political forces that shape the production and circulation of medical knowledge.
The Rise of RCTs
Physicians and medical researchers have attempted for millennia . . .
Journal Article
Outcomes and Statistical Power in Adult Critical Care Randomized Trials
by
Cooney, Elizabeth
,
Mikkelsen, Mark E.
,
Ratcliffe, Sarah J.
in
Adult
,
Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy
,
Biological and medical sciences
2014
Intensive care unit (ICU)-based randomized clinical trials (RCTs) among adult critically ill patients commonly fail to detect treatment benefits.
Appraise the rates of success, outcomes used, statistical power, and design characteristics of published trials.
One hundred forty-six ICU-based RCTs of diagnostic, therapeutic, or process/systems interventions published from January 2007 to May 2013 in 16 high-impact general or critical care journals were studied.
Of 146 RCTs, 54 (37%) were positive (i.e., the a priori hypothesis was found to be statistically significant). The most common primary outcomes were mortality (n = 40 trials), infection-related outcomes (n = 33), and ventilation-related outcomes (n = 30), with positive results found in 10, 58, and 43%, respectively. Statistical power was discussed in 135 RCTs (92%); 92 cited a rationale for their power parameters. Twenty trials failed to achieve at least 95% of their reported target sample size, including 11 that were stopped early due to insufficient accrual/logistical issues. Of 34 superiority RCTs comparing mortality between treatment arms, 13 (38%) accrued a sample size large enough to find an absolute mortality reduction of 10% or less. In 22 of these trials the observed control-arm mortality rate differed from the predicted rate by at least 7.5%.
ICU-based RCTs are commonly negative and powered to identify what appear to be unrealistic treatment effects, particularly when using mortality as the primary outcome. Additional concerns include a lack of standardized methods for assessing common outcomes, unclear justifications for statistical power calculations, insufficient patient accrual, and incorrect predictions of baseline event rates.
Journal Article
Randomization procedures in parallel-arm cluster randomized trials in low- and middle-income countries: a review of 300 trials published between 2017-2022
by
Mbuagbaw, Lawrence
,
Taljaard, Monica
,
Althabe, Fernando
in
Best practice
,
Cluster randomized trial
,
Clusters
2025
Cluster randomized trials (CRTs) are frequently used to evaluate interventions in low- and middle-income countries (LMICs). Robust execution and transparent reporting of randomization procedures are essential for successful implementation and accurate interpretation of CRTs. Our objectives were to review the quality of reporting and implementation of randomization procedures in a sample of parallel-arm CRTs conducted in LMICs.
We selected a random sample of 300 primary reports of parallel-arm CRTs from a database of 800 CRTs conducted in LMICs between 2017 and 2022. Data were extracted by two reviewers per trial and summarized using descriptive statistics.
Among 300 trials, 192 (64%) reported the method of sequence generation, 213 (71%) reported the type of randomization procedure used, 146 (49%) reported who generated the sequence, 136 (45%) reported whether randomization was implemented by an independent person, and 75 (25%) reported a method of allocation concealment. Among those reporting the methods used, suboptimal randomization procedures were common: 28% did not use a computer, 21% did not use restricted randomization, 58% did not use a statistician to generate the sequence, in 53% the person was not independent from the trial, and 80% did not use central randomization. Public randomization ceremonies were used in 10% of trials as an alternative method of allocation concealment and to reassure participants of fair allocation procedures.
The conduct and reporting of randomization procedures of CRTs in LMICs is suboptimal. Dissemination of guidance to promote robust implementation of randomization in LMICs is required, and future research on the implementation of public randomization ceremonies is warranted.
Cluster randomized trials (CRTs) are trials where entire groups, rather than individuals, are randomly assigned to different treatments (eg, intervention or usual care). This randomization process can be challenging in CRTs; clear reporting and proper execution are important to ensure fairness and accurate results. In this study, we reviewed how well randomization procedures were reported and carried out in 300 CRTs, selected from a larger database of 800 CRTs, conducted in low- and middle-income countries (LMICs), and published between 2017 and 2022. We found that reporting on key aspects of randomization was often incomplete: 64% reported how they created the random allocation sequence, 71% reported the type of randomization method used, 49% reported who generated the sequence, 45% reported whether a person independent from the trial handled the randomization, and 25% reported how they kept group assignments hidden until the intervention was ready to begin. Even when trials did reported these methods, many did not follow best practices: 28% did not use a computer, 21% did not apply techniques to ensure balanced treatment arms, 58% did not involve a statistician to generate the sequence, 53% had someone involved in the trial handle randomization (as opposed to an independent person), and 80% did not use central randomization to assign groups, where a third party reveals treatment assignment to groups. Interestingly, 10% of trials used public randomization ceremonies (events where group assignments are revealed in a public setting) to keep group assignments hidden until revealment and to reassure participants that the process was fair. Overall, we found that randomization procedures in CRTs were often not well reported or carried out optimally. It is important for researchers to follow established guidelines to ensure randomization is done properly in CRTs in LMICs. More research is also needed to understand how public randomization ceremonies are used in practice.
[Display omitted]
•Robust randomization methods are essential for cluster randomized trials (CRTs).•Improved adherence to reporting and best practices for randomization in CRTs is needed.•Public randomization ceremonies may help with implementation challenges.•Further research on the conduct of public randomization ceremonies is warranted.
Journal Article
The need for further guidance on the handling of multiple outcomes in randomized controlled trials: a scoping review of the methodological literature
by
Duarte, Rui
,
Jiang, Yimin
,
Wells, Valerie
in
Clinical trials
,
Complex intervention
,
Composite outcome
2025
To review current methodological guidance for handling and reporting of multiple outcomes (MOCs) in randomized controlled trials (RCTs).
A scoping review with bibliographic database searches including Embase, PubMed, and Web of Science up to January 16, 2025 was conducted. Inclusion criteria were articles that: (1) provide advice on the design, analysis, or reporting of RCTs using MOCs; and/or (2) discuss statistical approaches for handling MOCs in RCTs. Six specific websites were also checked for formal and reporting guidelines. Included articles were summarized using thematic analysis.
Searches retrieved 1716 articles of which 123 were included with additional 25 articles from updated search. Eight additional articles were identified by the specific website search. Six main subthemes on methodological recommendations for using MOCs were identified from 74 of 123 articles (60%): (1) need to prespecify outcomes and analysis, (2) multiplicity adjustment, (3) power and sample size implications, (4) secondary outcomes multiplicity, (5) considerations of MOCs correlation, and (6) specific applications of MOCs. Recommendations on coprimary and composite outcomes were also identified, including their features, analyses methods, reporting, and challenges. Statistical methods for analyzing MOCs were discussed in 53 of 123 articles (43%), with the majority describing modifications of pre-existing statistical approaches.
Current recommendations on using MOCs in RCTs focus primarily on statistical considerations and trials of licensing drugs or medical devices. Areas for further methodological research and guidance include reporting of the rationale for the use and selection of MOCs in RCTs and considerations for trials undertaken in nonregulatory setting, including complex interventions.
[Display omitted]
•Focus of multiple outcomes guidance is the statistical issues in regulatory trials.•Absence of wider methods/reporting considerations for multiple outcomes in trials.•Limited guidance on approaching and reporting of secondary outcomes multiplicity.
Journal Article
Both clinical trial register and electronic bibliographic database searches were needed to identify randomized clinical trials for systematic reviews: an evaluation study
by
Kaul, Tabea
,
Colombijn, Julia M.T.
,
Vernooij, Robin W.M.
in
Bias
,
Bibliographic data bases
,
Bibliographies
2024
To determine whether clinical trial register (CTR) searches can accurately identify a greater number of completed randomized clinical trials (RCTs) than electronic bibliographic database (EBD) searches for systematic reviews of interventions, and to quantify the number of eligible ongoing trials.
We performed an evaluation study and based our search for RCTs on the eligibility criteria of a systematic review that focused on the underrepresentation of people with chronic kidney disease in cardiovascular RCTs. We conducted a combined search of ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform through the Cochrane Central Register of Controlled Trials to identify eligible RCTs registered up to June 1, 2023. We searched Cochrane Central Register of Controlled Trials, EMBASE, and MEDLINE for publications of eligible RCTs published up to June 5, 2023. Finally, we compared the search results to determine the extent to which the two sources identified the same RCTs.
We included 92 completed RCTs. Of these, 81 had results available. Sixty-six completed RCTs with available results were identified by both sources (81% agreement [95% CI: 71–88]). We identified seven completed RCTs with results exclusively by CTR search (9% [95% CI: 4–17]) and eight exclusively by EBD search (10% [95% CI: 5–18]). Eleven RCTs were completed but lacked results (four identified by both sources (36% [95% CI: 15–65]), one exclusively by EBD search (9% [95% CI: 1–38]), and six exclusively by CTR search (55% [95% CI: 28–79])). Also, we identified 42 eligible ongoing RCTs: 16 by both sources (38% [95% CI: 25–53]) and 26 exclusively by CTR search (62% [95% CI: 47–75]). Lastly, we identified four RCTs of unknown status by both sources.
CTR searches identify a greater number of completed RCTs than EBD searches. Both searches missed some included RCTs. Based on our case study, researchers (eg, information specialists, systematic reviewers) aiming to identify all available RCTs should continue to search both sources. Once the barriers to performing CTR searches alone are targeted, CTR searches may be a suitable alternative.
[Display omitted]
Journal Article
Association between type 2 diabetes and risk of cancer mortality: a pooled analysis of over 771,000 individuals in the Asia Cohort Consortium
2017
Aims/hypothesis
The aims of the study were to evaluate the association between type 2 diabetes and the risk of death from any cancer and specific cancers in East and South Asians.
Methods
Pooled analyses were conducted of 19 prospective population-based cohorts included in the Asia Cohort Consortium, comprising data from 658,611 East Asians and 112,686 South Asians. HRs were used to compare individuals with diabetes at baseline with those without diabetes for the risk of death from any cancer and from site-specific cancers, including cancers of the oesophagus, stomach, colorectum, colon, rectum, liver, bile duct, pancreas, lung, breast, endometrium, cervix, ovary, prostate, bladder, kidney and thyroid, as well as lymphoma and leukaemia.
Results
During a mean follow-up of 12.7 years, 37,343 cancer deaths (36,667 in East Asians and 676 in South Asians) were identified. Baseline diabetes status was statistically significantly associated with an increased risk of death from any cancer (HR 1.26; 95% CI 1.21, 1.31). Significant positive associations with diabetes were observed for cancers of the colorectum (HR 1.41; 95% CI 1.26, 1.57), liver (HR 2.05; 95% CI 1.77, 2.38), bile duct (HR 1.41; 95% CI 1.04, 1.92), gallbladder (HR 1.33; 95% CI 1.10, 1.61), pancreas (HR 1.53; 95% CI 1.32, 1.77), breast (HR 1.72; 95% CI 1.34, 2.19), endometrium (HR 2.73; 95% CI 1.53, 4.85), ovary (HR 1.60; 95% CI 1.06, 2.42), prostate (HR 1.41; 95% CI 1.09, 1.82), kidney (HR 1.84; 95% CI 1.28, 2.64) and thyroid (HR 1.99; 95% CI 1.03, 3.86), as well as lymphoma (HR 1.39; 95% CI 1.04, 1.86). Diabetes was not statistically significantly associated with the risk of death from leukaemia and cancers of the bladder, cervix, oesophagus, stomach and lung.
Conclusions/interpretation
Diabetes was associated with a 26% increased risk of death from any cancer in Asians. The pattern of associations with specific cancers suggests the need for better control (prevention, detection, management) of the growing epidemic of diabetes (as well as obesity), in order to reduce cancer mortality.
Journal Article
Registry-based randomized controlled trials- what are the advantages, challenges, and areas for future research?
by
Lowerison, Mark
,
Sajobi, Tolulope T.
,
Menon, Bijoy K.
in
Advantages
,
Ambulatory care
,
Angioplasty
2016
Registry-based randomized controlled trials are defined as pragmatic trials that use registries as a platform for case records, data collection, randomization, and follow-up. Recently, the application of registry-based randomized controlled trials has attracted increasing attention in health research to address comparative effectiveness research questions in real-world settings, mainly due to their low cost, enhanced generalizability of findings, rapid consecutive enrollment, and the potential completeness of follow-up for the reference population, when compared with conventional randomized effectiveness trials. However several challenges of registry-based randomized controlled trials have to be taken into consideration, including registry data quality, ethical issues, and methodological challenges. In this article, we summarize the advantages, challenges, and areas for future research related to registry-based randomized controlled trials.
Journal Article