Medical Rehabilitation: Guidelines to Advance the Field With High-Impact Clinical Trials

The purpose of this Special Communication is to summarize guidelines and recommendations stemming from an expert panel convened by the National Institutes of Health, National Center for Medical Rehabilitation Research (NCMRR) for a workshop entitled The Future of Medical Rehabilitation Clinical Trials, held September 29-30, 2016, at the NCMRR offices in Bethesda, Maryland. The ultimate goal of both the workshop and this summary is to offer guidance on clinical trials design and operations to the medical rehabilitation research community, with the intent of maximizing the effect of future trials.     

The “pragmatic trial”: An essentially contested concept?

For over 50 years, clinical research methodology has wrestled with the problem of the lack of correspondence between tests of treatments and applications of treatments. The former comprise of trials featuring scrupulous control of patient eligibility, treatment compliance, clinician expertise, follow‐up intensity, and so on. In applying a validated treatment, the practitioner has to confront considerable real‐world variation in potential patients and in implementation regimes. The remedy, going by the name of “pragmatic trials,” is to conduct clinical trials in conditions corresponding more closely to everyday practice. This solution has proved easier to utter than to execute, and the paper reviews the extensive literature on pragmatic trials, seeking to assess whether it has terminated in clarity or contestation.     

Understanding explanatory and pragmatic trials: Examples from randomized controlled trials on vertebroplasty

ObjectivesTo better understand the explanatory–pragmatic distinction in the design and interpretation of randomized controlled trials (RCTs).MethodsWe review the explanatory–pragmatic distinction in clinical trial design. We use the PRECIS-2 tool to evaluate the trial design of selected RCTs on percutaneous vertebroplasty for osteoporotic vertebral compression fractures. We discuss difficulties in the selection of criteria and in the construction of PRECIS diagrams. We also examine how inconsistency in the selection of various items of trial design can cause confusion in the interpretation of results.ResultsThe selection of criteria and the scoring of multiple PRECIS domains were subjective and thus debatable. The pragmascope patterns of various vertebroplasty trials were heterogeneous. Many trials had both pragmatic and explanatory components. Some placebo-controlled trial goals seem to have been explanatory, but their design actually included enough pragmatic items such that the meaning of negative trial results remains ambiguous.ConclusionThe results of a trial cannot be interpreted without understanding the various design choices made along the explanatory-pragmatic spectrum.