Quality of life claims in trials of anti-hypertensive therapy.

The increasing use of so-called quality of life assessments in clinical trials can be seen as a laudable attempt to gather information about the impact of treatment on patients which goes beyond the purely clinical. However, there is a growing tendency for pharmaceutical companies to use quality of life claims in marketing strategies. The varying protocols and study populations, together with multicentre and multicountry trials and the variety of implied definitions of quality of life raise serious issues concerning the scientific credibility of conclusions about quality of life as an endpoint. This paper reviews reports of randomized controlled trials of anti-hypertensive therapy which used 'quality of life', assessed by patient-completed questionnaires, as one of the outcome variables. Criteria referring to definitions of quality of life, the validity and reliability of the measures used, administration procedures, treatment of data, adequacy of discussion of alternative explanations of the findings and the legitimacy of the findings are spelled out. It is concluded that none of the studies reviewed were justified in the claims made concerning differential effects of therapies on 'quality of life'.