Methodologic assessments of quality of life measures in clinical trials

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.

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.

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.

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).

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).