Inter-area variations in age-adjusted health status.

Data from the 1980 to 1981 National Health Interview Survey on morbidity, principally bed-disability days, was age standardized and indexed by region of the United States and metropolitan and nonmetropolitan residence within region. There were substantial differences in both age-specific and age-adjusted morbidity by place of residence. Age-specific hospital days as a percent of bed-disability days also showed striking differences by geographic area. Age- and morbidity-adjusted data on hospital use for the 31 largest standard metropolitan statistical areas (SMSAs) add considerably to the little information available on inter-city differences in health status and hospital use. Indirectly age-standardized data for the 31 SMSAs show large variations in both bed-disability days and the proportion of such days occurring in hospitals. These data seriously challenge the premise that age is a reliable proxy for health status when comparing hospital (or surgical) use of populations residing in different locales (e.g., small area variations in health care use). Dependence on age instead of health status to identify high and low hospital use areas will systematically favor areas where the population has low morbidity (age adjusted) and be adverse to areas that have high morbidity.