Clinical trials : journal of the Society for Clinical Trials
-
Historical Article
Parental consent to participation in a randomised trial in children: associated child, family, and physician factors.
Low participation rates in randomised controlled trials involving children are almost a universal problem, leading to high cost and low statistical power. Trial, parent/family, child, and physician factors have been reported to influence parental willingness to consent for paediatric trials. ⋯ Parent, child, and physician factors are associated with consent for trial participation, with most not being modifiable. Having a member of the research study team approach the parent for consent appears to be the only feasible strategy for increasing recruitment to randomised trials in this setting.
-
Consider a comparative, randomized clinical study with a specific event time as the primary end point. In the presence of censoring, standard methods of summarizing the treatment difference are based on Kaplan-Meier curves, the logrank test, and the point and interval estimates via Cox's procedure. Moreover, for designing and monitoring the study, one usually utilizes an event-driven scheme to determine the sample sizes and interim analysis time points. ⋯ The procedure discussed in this article can be a useful alternative to the standard PHs method in the survival analysis.
-
Randomized Controlled Trial
Addressing methodological challenges in implementing the nursing home pain management algorithm randomized controlled trial.
Unrelieved pain among nursing home (NH) residents is a well-documented problem. Attempts have been made to enhance pain management for older adults, including those in NHs. Several evidence-based clinical guidelines have been published to assist providers in assessing and managing acute and chronic pain in older adults. Despite the proliferation and dissemination of these practice guidelines, research has shown that intensive systems-level implementation strategies are necessary to change clinical practice and patient outcomes within a health-care setting. One promising approach is the embedding of guidelines into explicit protocols and algorithms to enhance decision making. ⋯ Methodological challenges are inevitable in the conduct of an RCT. The need to optimize internal validity by adhering to the study protocol is compromised by the emergent logistical issues that arise during the course of the study.
-
Randomized Controlled Trial
Increasing trial efficiency by early reallocation of placebo nonresponders in sequential parallel comparison designs: application to antidepressant trials.
The sequential parallel comparison (SPC) design was proposed to improve the efficiency of psychiatric clinical trials by reducing the impact of placebo response. It consists of two consecutive placebo-controlled comparisons of which the second is only entered by placebo nonresponders from the first. Previous studies suggest that in antidepressant trials, nonresponse to placebo can already be predicted after 2 weeks of follow-up. This would allow to reduce the first phase of the SPC design to further increase its efficiency. ⋯ This study suggests that SPC designs are highly efficient alternatives to a conventional RCT in indications where placebo response is high and substantial treatment effects are established after a relatively short follow-up period (i.e., after the first SPC design phase). We conclude that SPC designs can reduce sample size requirements and increase success rates of antidepressant trials.
-
The objective of a non-inferiority trial is to determine whether a new or existing treatment is not less effective than another existing or current treatment by more than a pre-specified margin, Δ, usually with the requirement that the new treatment has some other advantage such as reduced cost or lower toxicity. A possible but unusual result in a non-inferiority trial is for the confidence interval for the treatment effect to lie between zero and Δ, implying that the new treatment is both inferior and non-inferior to the control. Such a result could occur in non-inferiority trials with large sample sizes or large non-inferiority margins. The possibility of this scenario occurring has implications for interim analyses. In standard superiority trials, stopping guidelines are often based on the p value obtained from testing whether treatments are equally effective. In non-inferiority trials, however, even if a new treatment is found to be inferior to the control at an interim analysis, there may still be a reasonable chance of demonstrating non-inferiority in the final analysis. ⋯ Conditional power is an appropriate tool for defining stopping guidelines for futility in non-inferiority trials, particularly those with large non-inferiority margins.