Lower Airway Disorders

Pathophysiology SEASONAL TRENDS IN U.S. ASTHMA HOSPITALIZATIONS AND MORTALITY Weiss KB. JAMA. 1990;263:2323-2328. Purpose of the Study The purpose of this study was to make a comparison of the seasonal variation in asthma hospitalizations with mortality in the United States. Study Population Hospitalization (hospital discharges) data were obtained from the National Hospital Discharge Survey (sampling approximately 7% of US hospitals). Mortality data (death certificates) were obtained from the US Vital Records information system. Both encompassed the 5-year period, January 1, 1982 to December 21, 1986, and included data from all US residents. Methods Data were based on the recording of diagnostic code 493 of the International Classification of Diseases, Ninth Revision as either the cause of death or first-listed discharge diagnosis. Hospitalization and mortality rates were calculated using annual population estimates from the US Bureau of the Census. Data were compiled by age, sex, race, and region of the country. Findings General Trends. During the 5-year period asthma was reported as the principal discharge diagnosis for an estimated 458 000 hospitalizations annually (averaging 38 000 per month), with an average discharge rate of 1.92 per 1000 population. The highest rates were seen in children younger than 5 years old (4.47 per 1000 population) and for adults older than 65 years (3.32 per 1000 population). Hospitalization rates for nonwhites were nearly three times higher than those for whites. During the same 5-year period, there were 18 114 deaths due to asthma reported in all age groups in the US (average 300 per month), with an average annual mortality rate of 1.52 per 100 000 population.