Stabilization of asthma mortality

Abstract

Background: Rates of death from asthma in the United States have increased since 1978.

Objective: To identify and evaluate recent trends in asthma mortality.

Methods: Analysis of data from the National Center for Health Statistics identifying asthma (ICD 493) as the underlying cause of death in the 50 United States and the District of Columbia with rates of death from asthma by age, race, and sex and age-adjusted rates of death by race. The Bureau of the Census provided population data by age, race, and sex that permitted calculation of rates of death at 5 through 34 years of age. The Departments of Health of Australia, Canada, Great Britain, and New Zealand provided numbers of deaths from asthma and population data from which we have calculated rates of death.

Results: Rates of death from asthma in the United States increased from .8 per 100,000 general population in 1977 and 1978 to 2.0 in 1989 and have been 1.9 or 2.0 since then until an increase to 2.1 in 1994. A significant difference in regression over groups indicates a difference in average rates between 1979 through 1987 compared with 1988 through 1994. Rates of death from asthma have been much higher for white females than white males with an increasing disparity. Rates of death from asthma at 5 through 34 years of age have been much greater in blacks than whites with no significant change in rates across time from 1980 through 1994. Age-adjusted rates for blacks over all ages increased from 1.5 in 1977 and 1978 to 3.5 in 1988 with rates no higher than that until an increase to 3.7 in 1994. Age-adjusted rates for whites increased from .5 in 1977 to 1.2 by 1989 with none higher than that since then through 1994. Comparison of slopes indicates a significantly greater increase for blacks than whites (F = 68.296, P < .0001). Equality of slopes tests indicate significantly greater age-adjusted rates of increase for each race separately for 1979 through 1987 compared with 1988 through 1994.

Conclusion: Since 1988 rates of death from asthma in the United States for most ages have stabilized at rates more than 50% higher than those of 1979, but there has been only a suggestion of stabilization of rates at 5 through 34 years of age, ages at which certification of death as due to asthma is most accurate. Rates of death have been much higher for blacks than whites, and among whites rates have increased more for females than males. These differences might be due to difference in prevalence or severity of differences in accuracy of diagnosis. Improvements in management would reduce asthma mortality.