20-YEAR TRENDS IN THE PREVALENCE OF ASTHMA AND CHRONIC AIR-FLOW OBSTRUCTION IN AN HMO

Although asthma is on the rise in the United States and elsewhere, dat a on age-sex-specific patterns of change in various types of health ca re utilization are scarce. We report on 20-yr trends in the treated pr evalence of asthma among members of a large health maintenance organiz ation. Data are presented separately for each of six age-sex categorie s, and include both the treated prevalence of asthma as well as the tr eated prevalence of the broader category of chronic airflow obstructio n (CAO), defined as asthma, chronic bronchitis, or emphysema. During t he period 1967-1987 the treated prevalence of asthma and CAO increased significantly in all age-sex categories except males aged 65 and olde r. These patterns are in contrast to previous studies of this populati on that showed that increases in asthma hospitalizations and hospital- based episodes of care were limited primarily to young boys. Not only do these findings support other evidence of a real increase in asthma prevalence, but they also highlight the risks associated with drawing inferences about changing disease epidemiology based on a single type of health care utilization.