In-hospital mortality rates from acute myocardial infarction by race in U.S. hospitals: findings from the National Hospital Discharge Survey.

Mortality rates in the United States from coronary artery disease are higher among blacks than whites at younger ages, with a crossover to lower rates above the age of 70. The factors that determine this crossover of age-specific death rates have not been elucidated. Selection from the black population of younger individuals who are sicker by virtue of being more coronary prone might leave a relatively healthier group of older persons. Support for this hypothesis would consist in part of evidence that coronary artery disease has an earlier onset in the black population. We examined data from the National Hospital Discharge Survey for the years 1973-1984 to determine if age-related differences in case-fatality rates existed between whites and nonwhites. In-hospital case fatality rates were 10% to 70% higher for each of the 10 year age groups for nonwhites up to age 70, at which time a crossover occurred. The median age at death from myocardial infarction was approximately 5 years younger in nonwhites compared with whites. National estimates of hospitalization rates for myocardial infarction from these data likewise suggest that nonwhites receive less health care for coronary artery disease than whites relative to recorded fatal events. The age-specific trends in case-fatality support the hypothesis that a cohort selection effect in part determines the black/white differentials in coronary artery disease. Relative susceptibility of the black and white population is thus not appropriately estimated by age-adjusted rates, but should be examined on an age-specific basis within the framework of selection effects on a cohort.