The influence of age and sex on asthma admissions.

To describe demographic data from a large population of asthmatic patients to define the role of age and sex as risk factors for asthma admission. A retrospective review of all asthma admissions as defined by International Classification of Diseases, Ninth Revision, code 493.0. All medical-surgical admissions from 67 hospitals in five counties of southeastern Pennsylvania from 1986 through 1989. Patients admitted for asthma treatment (33,269) were reviewed. In the 0- to 5-year-old and 6- to 10-year-old age groups, males were admitted nearly twice as often as age-identical females. In the 11- to 20-year-old age group, admissions for males and females were nearly identical. Between 20 and 50 years of age, the female-to-male ratio was nearly 3:1. Thereafter, females were admitted for asthma at a rate of about 2.5:1 when compared with their age-equivalent male counterparts. Length of stay increased proportionally as the patient age increased. After 30 years of age, the length of stay was slightly greater for females than males. There is a much higher rate of admission for prepubertal males than females. However, there is a higher incidence of asthma admissions for adult females than adult male asthmatic patients, and female asthmatic patients experience longer hospital stays per admission as well. These data indicate that adult females are more severely affected by asthma and raise the possibility that hormonal or biochemical differences related to sex may play a role in the pathophysiology of asthma.