Objective: To assess the feasibility of utility measurement in patients with ankylosing spondylitis (AS) or fibromyalgia (FMS). Patient derived utilities provide overall estimates of the impact of a disease on patient well being.
Methods: The Maastricht Utility Measurement Questionnaire was applied cross sectionally to 57 patients with AS and 86 outpatients with FMS. By means of rating scale and standard gamble techniques, patients were asked to value their own health state.
Results: All 143 patients completed the interview. Patients with AS valued their personal health state on the rating scale (0-100) considerably higher than patients with FMS (AS: 69 and FMS: 54). Standard gamble utility values (0-1), however, were about the same at a higher level (AS: 0.86 and FMS: 0.83). Four weeks test-retest reliability was examined in 15 patients with FMS. The intraclass correlation coefficient of the utility score for the patient's own health state was 0.56 for the rating scale and 0.66 for the standard gamble technique.
Conclusion: Feasibility of the Maastricht Utility Measurement Questionnaire was generally satisfactory in both patient groups. Utility values obtained by rating scale and standard gamble technique differed considerably. Our data support the view that utility measurement is sensitive to the method chosen to elicit patient well being.