QUALITY-OF-LIFE AS AN OUTCOME MEASURE

It is important to identify unknown and unquantified benefits and risk s of therapeutic intervention that are reflected in the quality of lif e. This is especially important when the benefit : risk analysis is no t clearly in favour of treatment. Quality of Life is defined and targe t areas identified. The steps in the measurements of quality of life a re discussed, including the validity, repeatability and sensitivity to change of existing methods; their acceptability, analytical problems; the presentation of the results; and the use of the results in econom ic evaluations. The Sickness Impact Profile, the Nottingham Health Pro file and the Quality of Well-Being scale are compared for the assessme nt of patients with angina. The advantages and disadvantages of each i s discussed together with the results from a double-blind trial of tre atment in angina where the Sickness Impact Profile was employed. Gener ic and disease-specific instruments are compared. The advantages and d isadvantages of economic evaluations employing quality-of-life outcome s are discussed. Methods should be employed that withstand rigorous sc ientific evaluation. Both a health profile and a summary statistic suc h as a Health Status Index should be measured. If different treatments are to be compared, a randomised controlled trial should be employed. If the more expensive treatment is likely to be superior then costs s hould be collected and a cost-utility analysis performed.