Incidence and outcomes of asthma in the elderly: A population-based study in Rochester, Minnesota

Study objective: To estimate the incidence of asthma in an elderly population and to describe the clinical characteristics, use of health services, and long-term survival of persons with onset of asthma after age 65 years. Design: Retrospective cohort study. Setting: Rochester, Minn. Patients: All Rochester, Minn, residents age 65 years or older who met criteria for onset of definite or probable asthma from 1964 through 1983. Interventions: None. Measurements and results: Ninety-eight Rochester residents (52 female, 46 male) with onset of asthma at or after age 65 years were identified. The age- and sex-adjusted incidence was 95/100,000 (95% confidence interval, 76 to 115/100,000). The age-specific incidence of asthma was 103/100,000 in residents aged 65 to 74 years, 81/100,000 in those aged 75 to 84 years, and 58/100,000 in residents older than 85 years. Only 11% had allergy skin tests, 24% had at least one office peak flow measurement, and 43% had at least one spirometry measurement. After the diagnosis of asthma, 40% had unscheduled ambulatory visits, 22% had emergency department visits, and 42% had at least one hospitalization for asthma. Observed survival was not significantly different from expected survival. Conclusions: Asthma is common in the elderly. Diagnostic evaluation was less intensive than present guidelines recommend. Following the diagnosis of asthma, a substantial proportion of these individuals required unscheduled ambulatory visits, emergency department visits, or hospitalizations. Asthma with onset after age 65 years was not associated with reduced survival.