title: Issues in subgroup analyses and meta-analyses of clinical trials.
abstract: This commentary discusses two techniques commonly used to analyze clinical trials: subgroup analysis and meta-analysis. Subgroup analysis is used to evaluate the consistency of a treatment across multiple groups, usually within a clinical trial. Subgroup analysis often is used to generate or test an hypothesis about risk factors or treatment responses. Meta-analysis (overview) is used primarily to summarize data from several randomized clinical trials and to evaluate consistency among trials. Meta-analysis is a formal way of summarizing the totality of information coming from well-conducted randomized clinical trials. The use and limitations of these two techniques are discussed.
authors.affiliation: Departments of Medicine and Pharmacology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA. jtb2@columbia.edu
authors.forename: J Thomas
authors.initials: JT
authors.lastname: Bigger
mesh_terms: D015982:Bias; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy; D002986:Clinical Trials as Topic / Q000379:methods* / Q000592:standards; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D019317:Evidence-Based Medicine / Q000379:methods*; D006801:Humans; D015201:Meta-Analysis as Topic; D018579:Patient Selection; D016032:Randomized Controlled Trials as Topic / Q000379:methods; D015203:Reproducibility of Results; D012107:Research Design / Q000592:standards; D018570:Risk Assessment / Q000379:methods* / Q000592:standards; D012307:Risk Factors; D018401:Sample Size; D012680:Sensitivity and Specificity; D016896:Treatment Outcome