Pragmatic Clinical Trials: Implementation Opportunity, or Just Another Fad?

Abstract

Clinical trials have been characterized as either explanatory or pragmatic in nature based on whether the major objective of the trial is to prioritize internal or external validity.1 Explanatory trials prioritize internal validity by minimizing clinician and patient biases, but, in doing so, they are generalizable only to “ideal” conditions. In contrast, pragmatic trials prioritize external validity by studying interventions in the context of broadly based and routine clinical practice conditions. The term pragmatic was coined for research trials in the 1960s2; however, since that time, alternative descriptors have been used to define trial designs in which generalizability is the primary goal, including practical trials, large simple trials, real-world trials, management trials, and effectiveness trials.1 Although there is considerable overlap in these labels, “pragmatic” has come to the forefront primarily for 2 reasons: (1) the advent of the Pragmatic Explanatory Continuum Indicator Summaries (PRECIS),3,4 an intuitive tool to characterize a clinical trial on an explanatory-pragmatic spectrum, and (2) reporting standards for pragmatic clinical trials that have been formalized through an extended version of the Consolidated Reporting Trials (CONSORT).5 The PRECIS tool comprehensively dissects a clinical trial by eligibility criteria, recruitment methods, settings, clinician expertise, intervention delivery flexibility, adherence strategies, intensity of follow-up, relevancy of outcomes, and primary analysis strategies and characterizes each category on an explanatory-pragmatic spectrum. Although lack of detail in trial reporting makes true quantitative analyses difficult,6 attempts at quantifying the percentage of published trials that are pragmatic indicate that pragmatic trials are infrequent—less than 2% of trials, according …