Changing patterns of acute myocardial infarction: decline in period prevalence and delay in onset.

The rural Pee Dee area of South Carolina has had the highest mortality rate in the nation for coronary heart disease. Community surveillance shows a 22.7% (p = 0.0008) decline in fatal and nonfatal acute myocardial infarction (AMI) rates during the period 1978 to 1985 in the Pee Dee area. Rates for white men decreased 32% (p = 0.001), whereas in other race-sex groups changes were not significant, although there was a downward trend (p = 0.18) among black men. Among white men decreases in the AMI rates occurred in each of the decades of age 35 to 64 years. In all race-sex groups there was a sharp increase in rates between 1978 and 1985 for those 65 to 74 years of age, suggesting that the incidence of AMI was delayed to a later age. Out-of-hospital AMI death rates declined markedly in all race-sex groups: 63% for white men, 62% for white women, 49% for black men, and 39% for black women. Overall case fatality rates declined from 14% (27 of 193) to 10% (23 of 232), but the decrease was not statistically significant.

Acute myocardial infarction: period prevalence, case fatality, and comparison of black and white cases in urban and rural areas of South Carolina.

Community surveillance revealed 1085 prevalent cases of acute myocardial infarction (AMI) during 1978 in urban metropolitan Columbia and rural Pee Dee areas of South Carolina. Six hundred fifty-eight hospitalized cases met our criteria and were classified as definite or probable. Death certificates identified 427 who died before admission to the hospital and who were classified as unvalidated. However, there is need to verify death certificate diagnosis in out-of-hospital deaths which account for approximately two thirds of total cases in blacks and about one third of white cases. Other findings were: White males had higher AMI rates in the rural Pee Dee area than in urban Columbia, while black males and black females had higher rates in Columbia than in the Pee Dee area and white females had similar rates in both areas. Rates for out-of-hospital AMI mortality were higher in blacks than in whites. Out-of-hospital AMI mortality rates in Columbia and the Pee Dee area were four times higher than in Minneapolis-St. Paul in 1978. For definite and all criteria AMI, white males had the highest rates, double the black male rate except for all criteria AMI in Columbia, where white male and black male rates were similar. Urban cases of both races experienced more anterior infarctions than rural cases.