Methodologic assessments of quality of life measures in clinical trials

OBJECTIVE: To provide a comprehensive overview and to evaluate the quality of published clinical trials assessing the effect of drug therapy on patients' quality of life. DATA SOURCE: Clinical trials that assessed the effect of drug therapy on patient quality of life published in English, peer-reviewed journals were identified through a MEDLINE search (1966-1995) and review of references from recent publications. DATA EXTRACTION: A data collection form was used to record information on trial demographics, quality-of-life assessment, study design, and statistical analyses. A quality score was computed for each article based on a checklist of items. RESULTS: Two hundred sixty-five articles were eligible for this study Reliability data on the quality-of-life instruments were provided by 23.8% of the studies and validity data were provided by 21.5%. Quality of life was defined in about 14% of the trials, while 15% provided the rationale for selecting the specific instrument(s). The average overall quality score for the trials was 0.34, based on a scale of 0-1. The trials with quality-of-life scores as the primary end point had significantly higher quality scores than those designed primarily to measure clinical outcomes (p < 0.05). CONCLUSIONS: Although there was a gradual but significant improvement in the quality of published clinical trials over time, more attention should be paid to various aspects of quality-of-life assessment (e.g., defining construct, instrument selection).