title: Meta-analysis of NSAIDs: contribution of drugs, doses, trial designs, and meta-analytic techniques.
abstract: To elucidate potential bias sources in meta-analyses, I studied whether the effect of nonsteroidal, anti-inflammatory drugs on joint count in patients with rheumatoid arthritis was related to trial design (active or placebo control), sample size, duration of treatment, drop-out rate, the existence of a wash-in period, drug, dose, and meta-analytic technique. In short-term trials, none of the covariates was related to the effect size. No differences between drugs or doses were found in usual gold standard meta-analyses, comparing drugs within trials before pooling. In a meta-analysis of treatment arms, however, four drugs were either significantly more or less effective than average, but these deviations were spurious. In meta-analyses of NSAIDs, indirect comparisons may allow a preliminary comparison of drugs that have not been compared directly. Treatment arms should be compared within trials before pooling, however.
authors.affiliation: Institute of Biostatistics and Theory of Medicine, Panum Institute, University of Copenhagen, Denmark.
authors.forename: P C
authors.initials: PC
authors.lastname: Gøtzsche
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D004311:Double-Blind Method; D006801:Humans; D015201:Meta-Analysis as Topic; D008875:Middle Aged; D010919:Placebos; D016032:Randomized Controlled Trials as Topic; D012107:Research Design
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D010919:Placebos