The psychometric properties of patient preferences in osteoporosis

Objective. Osteoporosis is a chronic disease manifested by wrist, vertebral , and hip fractures that results in significant morbidity and burden to soc iety. About 30% of postmenopausal women have osteoporosis according to the WHO criteria, Women with one vertebral fracture have a 4-fold increased ris k of a subsequent fracture. The goal of treatment is to prevent fractures a nd improve quality of life. Preferences or utilities are now recommended fo r incorporating quality of life into evaluations of the cost effectiveness of new therapeutic interventions. We evaluated the psychometric properties of preference based measures in osteoporosis. Methods, Preference scenarios were constructed with a health state classifi cation system. The reliability and validity of the feeling thermometer and the standard gamble was assessed by interviewing 42 women from 4 different patient groups. The sensitivity to change of the feeling thermometer and st andard gamble was compared with the Health Utilities Index Mark 2 (HUI2) an d SF-36. All subgroups were reassessed about 2 months after their first int erview. Results, Preference measurement was feasible in women of different age grou ps. The reliability coefficients for health states ranged from 0.65 to 0.87 . The preference scores for the marker states demonstrated content validity . Convergent validity of the feeling thermometer was supported by a signifi cant correlation with the HUI2 (r = 0.38, p < 0.05) and the physical health summary of the SF-36 (r = 0.56, p < 0,005). The standard gamble did not co rrelate with the HUI2 (r = 0.15) or the feeling thermometer (r = 0.09), but correlated with 2 domains of the SF-36. The preference measures were sensi tive to change. with the efficiency scores ranging from 0.78 to 1.0. Conclusion. Preference measurements in the evaluation of osteoporosis are f easible, The feeling thermometer and standard gamble appear to be related t o different aspects of health related quality of Life. Both instruments wer e sensitive to change over a 2 month period.