New developments in medical clinical trials.
This paper reviews several new developments and long-standing good practices for conducting clinical trials. Discussion starts with the need for clear statements of study objectives, proceeds to clarify target and sample population, and elaborates on primary vs. secondary variables with the need for alpha adjustment in the presence of multiple outcomes. Here we also review the issue of surrogate endpoints. Study design issues--including blinding, randomization, and multicenter studies--come next. Then we discuss the current trend of the replacement of placebo-controlled trials by active controlled non-inferiority trials, the increasing use of Independent Data Monitoring Committees, the prominence of analysis on Intention-to-Treat samples, and the importance of imputation of missing data. We close with a brief discussion of the unit of analysis, the role of newer statistical analysis methods, safety issues, subset analysis, and, most importantly, clinical significance.
Boston University, Mathematics and Statistics Department, Statistics and Consulting Unit, 111 Cummington St., Boston, MA 02215, USA. ralph@bu.edu
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D'Agostino
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Massaro
D026661:Clinical Trials Data Monitoring Committees; D002986:Clinical Trials as Topic / Q000379:methods / Q000639:trends*; D018849:Controlled Clinical Trials as Topic; D006801:Humans; D015337:Multicenter Studies as Topic; D016032:Randomized Controlled Trials as Topic; D012107:Research Design