METHODS OF RANDOMIZED CONTROLLED CLINICAL-TRIALS IN HEALTH-SERVICES RESEARCH

The randomized controlled clinical trial is an increasingly used metho d in health services research. Analysis of methodology is needed to ac celerate practical implementation of trial results, select trials for meta-analysis, and improve trial quality in health services research. The objectives of this study are to explore the methodology of health services research trials, create and validate a streamlined quality ev aluation tool, and identify frequent quality defects and confounding e ffects on quality. The authors developed a quality questionnaire that contained 20 evaluation criteria for health services research trials. One hundred one trials from the Columbia Registry of Controlled Clinic al Trials were evaluated using the new quality tool. The overall agree ment between independent reviewers, Cohen's kappa, was 0.94 (+/-0.01). Of a possible score of 100, the trials received an average score of 5 4.8 (+/-12.5). Five evaluation criteria indicated significant quality deficiencies (sample size, description of case selection, data on poss ible adverse effects, analysis of secondary effect variables, and retr ospective analysis). The quality of study characteristics was signific antly weaker than the quality of reporting characteristics (P < 0.001) . The total average scores of Medline-indexed journals were better tha n the non-Medline-indexed journals (P < 0.001). There was a positive c orrelation between the overall quality and year of publication (R = 0. 21, P < 0.05). The authors conclude that the new quality evaluation to ol leads to replicable results and there is an urgent need to improve several study characteristics of clinical trials. In comparison to dru g trials, site selection, randomization, and blinding often require di fferent approaches in health services research.