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Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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PubMed2026

Understanding randomized controlled trial generalizability through an embedded molecular diagnostics trial.

BACKGROUND: Issues with randomized controlled trial generalizability are well described, but whether these issues result from differences in patient treatment across contexts remains unknown. We studied treatment of patients with high-risk prostate cancer after radical prostatectomy inside and outside a randomized controlled trial evaluating the impact of a genomic classifier on post-radical prostatectomy treatment decision making (Genomics in Michigan Impacting Observation of Radiation [G-MINOR]; ClinicalTrials.gov identifier NCT02783950). METHODS: G-MINOR enrolled 338 patients; propensity score-matched eligible but unenrolled patient cohorts (pretrial and trial contemporary) from the Michigan Urological Surgery Improvement Collaborative (MUSIC), in which the trial was embedded, were compared for rates and time to secondary treatment (adjuvant or salvage therapy) after prostatectomy. RESULTS: Among 338 patients in the G-MINOR cohort, 69 (31 adjuvant, 38 salvage) received secondary treatment compared with 266 (183 adjuvant, 83 salvage) and 104 (60 adjuvant, 44 salvage) in the 1014 contemporary and 338 pretrial-matched MUSIC cohorts. Time to secondary treatment was much shorter in the MUSIC cohort across all comparisons. For example, matching G-MINOR to synchronous MUSIC patients demonstrated 84% vs 74% estimated 2-year treatment-free survival for trial and real-world patients, respectively (P < .001). CONCLUSIONS: Controlling for key clinicopathologic factors, patients in the G-MINOR randomized controlled trial and MUSIC cohorts were treated differently, even after stratifying by genomic risk. These findings suggest that challenges in randomized controlled trial generalizability extend beyond the representativeness of trial participants. Differences in management may also explain why divergent patient outcomes are observed in randomized controlled trials vs real-world settings.

Aged↗

PubMed1998

Preventing discrimination against volunteers in prophylactic HIV vaccine trials: lessons from a phase II trial.

CONTEXT: Preventive HIV vaccines can temporarily cause uninfected individuals to have positive results on HIV testing. As preparations are underway to mount larger efficacy trials, the social risks of trial participation should be studied. OBJECTIVE: To describe frequency of HIV testing and discrimination among participants in a preventive phase II HIV vaccine trial. PARTICIPANTS: 266 vaccine trial volunteers were eligible; 247 participated in a confidential survey. RESULTS: 63 volunteers (26% of respondents) reported 185 HIV tests during the prior 12 to 24 months; most tests were for other research studies, health care, insurance, incarceration, or employment. Only 5 volunteers reported having positive HIV test results. Volunteers reported 99 adverse social incidents or problems, 53 of which were related to the trial. The most common type of event occurred when volunteers disclosed their trial participation and were mistakenly presumed to be infected with HIV. Few reported difficulty obtaining insurance, job loss, and inadvertent disclosure of their participation in the trial. CONCLUSION: In this vaccine trial, few serious social harms were reported. Those who conduct HIV tests for insurance, employment, health care, or other reasons should be made aware that HIV vaccines can cause false-positive HIV test results. Those planning future trials must continue to provide needed support to volunteers. Social harms should be monitored with the same vigilance accorded to physical harms.

AIDS Serodiagnosis↗

PubMed2005

The journal impact factor as a predictor of trial quality and outcomes: cohort study of hepatobiliary randomized clinical trials.

OBJECTIVES: To examine the association between the impact factor and characteristics of hepatobiliary randomized clinical trials. METHODS: A cohort study of 530 hepatobiliary randomized clinical trials was performed. The journal impact factor was extracted from Science Citation Index. For each trial, we extracted the sample size, the quality of randomization and blinding methods, and the statistical significance of the primary outcome measure. RESULTS: The median sample size was 45 participants (interquartile range 25-88). The allocation sequence generation was adequate in 273 trials (52%). Allocation concealment was adequate in 178 trials (34%). The primary outcome measure was statistically significant in 374 (71%) trials. Nonparametric analyses for trend indicated that the impact factor was significantly associated with the sample size (p < 0.01) and the proportion of trials with adequate allocation sequence generation (p < 0.01) or allocation concealment (p= 0.02). The impact factor was not significantly associated with the study outcome (p= 0.28). CONCLUSIONS: The present study supports the use of the impact factor as a rough quality indicator. However, even trials in high impact journals may be small or may have inadequate quality. Critical appraisal of individual trials is always necessary, irrespective of the place of publication.

Bibliometrics↗

PubMed2000

The importance of considering trial design when interpreting clinical trial results.

BACKGROUND: In recent decades, clinical trials have played an increasingly important role in determining how we practice. Trial results proving that a clinical finding poses risk have led to interventions that try to reduce risk. Clinical trials proving that a particular therapy provides better outcome than another therapy have changed the therapies we now use. Unfortunately, the results of clinical trials are too often affected by biases or design issues that may overtly or covertly alter the results or the way they should really be used. In addition, these biases and design and analysis issues are rarely evident in the abstract sections or key figures and tables in the publications reporting the trials, which may be all the busy physician either reads or remembers. METHODS AND MATERIALS: This manuscript discusses the issues involved in optimally understanding clinical trial design and interpretation so that practitioners can better understand how to intelligently read and apply trial results to clinical practice. CONCLUSIONS: Clinical trial results can not be properly applied without consideration of trial design features and intertrial comparisons.

Anti-Arrhythmia Agents↗

PubMed2006

How much does pre-trial testing influence complex intervention trials and would more testing make any difference? An email survey.

BACKGROUND: The UK Medical Research Council has proposed that complex interventions should be tested in exploratory trials prior to a full-scale trial so as to better define the intervention and test the feasibility of components such as recruitment. It is not clear to what extent this is being done. This study aimed to determine to what extent complex interventions are tested prior to a full-scale trial and whether more or different testing would have led to a different intervention being used in the trial. METHODS: Email survey of the authors of complex intervention trials published in seven major journals in 2004. RESULTS: 72% (50/69) of eligible authors replied. Eight authors did not consider their interventions to be complex. The majority of respondents' complex interventions were tested (34/42): some extensively. Conversely, only 17 of the 34 published reports describing these trials mention testing. Two-thirds (22/34) of those testing their interventions did not believe that more or different testing would have produced a more effective intervention. 31% (13/42) of all authors did believe further testing would have led to improvements. Five respondents mentioned a lack of funding as a reason for not doing more testing. CONCLUSION: Complex interventions are generally tested prior to their evaluation in a full-scale trial, although the amount of testing varies. Testing is often not described in trial reports, which makes it hard to judge whether a trial result could be improved with a better intervention, or whether further work with a different intervention is required.

Attitude of Health Personnel↗

PubMed1993

Ethical dilemmas in continuing a zidovudine trial after early termination of similar trials.

Ethical dilemmas caused by external events and an interim subset analysis raised concerns about continuing a long-term VA clinical trial comparing early with later zidovudine therapy for symptomatic human immunodeficiency virus (HIV) infection. The first external event was the early termination of other, apparently similar, trials conducted by the AIDS Clinical Trials Group (ACTG) and the announced clear benefits for the zidovudine-treated patients. Interim analysis of the VA trial at this time did not show similar benefits. Subset analyses were performed to explore factors that might explain the different results. These suggested a difference in response to zidovudine in white and minority groups. The Data Monitoring Board and a special advisory panel reviewed these data and concluded that, since the VA results were neutral overall and the subset analyses based on small numbers, the trial should continue. By conference call, the study cochairmen and biostatistician discussed this decision with study personnel without revealing interim results, and study personnel passed the information on to patients at the participating centers. The second event was in March 1990, when the Food and Drug Administration (FDA) approved earlier use of zidovudine, which applied to patients still in the VA trial. Patients were asked to reaffirm their participation by signing a new informed consent that explained the findings reported by the ACTG, the FDA-approved revised recommendations, and the rationale for continuation of the VA trial. The consent form emphasized that continued masked therapy was optional and that unmasked treatment and follow-up would be provided to patients requesting it. Seventy-four percent of the participants chose to continue masked therapy. We conclude that when new external data are announced, informed participation in a long-term clinical trial may require a revised consent form and that it is ethical and practical to present this without disclosure of interim study results.

Acquired Immunodeficiency Syndrome↗

PubMed1978

The importance of beta, the type II error and sample size in the design and interpretation of the randomized control trial. Survey of 71 "negative" trials.

Seventy-one "negative" randomized control trials were re-examined to determine if the investigators had studied large enough samples to give a high probability (greater than 0.90) of detecting a 25 per cent and 50 per cent therapeutic improvement in the response. Sixty-seven of the trials had a greater than 10 per cent risk of missing a true 25 per cent therapeutic improvement, and with the same risk, 50 of the trials could have missed a 50 per cent improvement. Estimates of 90 per cent confidence intervals for the true improvement in each trial showed that in 57 of these "negative" trials, a potential 25 per cent improvement was possible, and 34 of the trials showed a potential 50 per cent improvement. Many of the therapies labeled as "no different from control" in trials using inadequate samples have not received a fair test. Concern for the probability of missing an important therapeutic improvement because of small sample sizes deserves more attention in the planning of clinical trials.

Clinical Trials as Topic↗

PubMed1997