American journal of physical medicine & rehabilitation
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Am J Phys Med Rehabil · Jul 2001
ReviewConducting clinical trials to establish drug efficacy in chronic pain.
Design of clinical trials to establish drug efficacy in chronic pain is a complicated issue, and numerous factors must be considered in identifying an optimal study design. Investigators should begin by identifying a focused and testable research question, with the outcome variables operationalized in a way that allows appropriate quantitative analysis. The prospective, randomized, placebo-controlled, doubled-blind study using validated quantitative measures is considered the optimal clinical trial design. ⋯ Sample selection issues must be considered during study design, including the sample size required (based on statistical power analysis), appropriate inclusion and exclusion criteria, and likely availability of qualifying patients. There are numerous statistical options for analyzing data that must be selected based on whether data are parametric or nonparametric, whether within-subject (crossover) or between-subject comparisons are used, and whether baseline values of outcome measures affect the degree of change in these measures over the course of the study. Involvement of a biostatistical consultant is recommended during all phases of clinical trials.