Quantifying the effect of health status on health care utilization using a preference-based health measure.

The purpose of this study was to quantify the effect of health status on current and future payments and number of visits to health professionals in a large, representative community sample in British Columbia, Canada. The study population was comprised of all respondents to the 1994/5 cycle of the Canadian National Population Health Survey (NPHS) who were 12 years of age or older and residing in the province of British Columbia (N = 2084). Health status was measured with the Health Utilities Index (HUI). Two outcomes were defined for each subject: (a) the sum of all healthcare costs covered by the Medical Services Plan, incurred during a given fiscal year, and (b) the total number of visits to all health practitioners during the same year. Outcome data were obtained for a period 1994-1998. We examined the relationship between the HUI and healthcare use in a multivariate log-linear model. In the full sample, better health in 1994-1995 was associated with lower healthcare cost and lower number of visits from 1994 through 1998. The overall adjusted cost ratio was 0.89 (99% CI = 0.85, 0.94) and the overall adjusted visit ratio was 0.91 (99% CI + 0.87, 0.95). The effect of health status on the costs of care and on the number of visits was similar in men and women, was stronger in persons less than 45 years of age compared to those 45+, and was not different according to place of residence. We conclude that the HUI is a strong predictor of health services use over 5 years. A 0.1 improvement in health utility is associated with a 10% reduction in the costs of care and number of visits to health professionals.