Recent trends in myocardial infarction rates in northern Italy. Results of the IM MONICA and CAMUNI registers in Brianza: 1993-1994 versus 1997-1998 [Recenti andamenti temporali dei tassi di infarto miocardico in nord Italia. Risultati dei registri IM MONICA e CAMUNI in Brianza: 1993-1994 versus 1997-1998]

Background. Previously reported time trends of myocardial infarction rates in the MONICA Brianza 35-64-year-old population showed a clear decline in coronary heart disease mortality, mostly attributable to concurrent reductions in myocardial infarction attack rates, and to a lesser extent in 28-day case fatality. The aims of this study were to estimate time trends in more recent years (up to 1997-1998) in the same population and in the same age range, and to assess the impact of myocardial infarction among 35-74-year-old residents, an age range never investigated before in Italy using standardized population-based registers. Methods. The myocardial infarction register in the Brianza population was resumed in 1997-1998, adopting the same standardized methods for data collection and classification of suspect coronary events as the WHO MONICA project, including the age group 65-74 years in addition to age groups usually covered. Age-specific and age-standardized rates of validated coronary mortality rates, of attack rates, and incidence rates and of 28-day case fatality were calculated. Time changes were estimated as the difference in rates. Results. In comparison to the rates among 35-64-year-old residents, the 35-74 age-standardized rates of coronary event mortality in the biennium are more than 3 times higher in women and more than twice in men. Similarly, the attack and incidence rates increased respectively from 243 to 381 and from 197 to 292 per 100 000 in men, from 38 to 107 and from 33 to 87 per 100 000 in women. Statistically significant reductions are observed in coronary death rates, myocardial infarction attack rates and 28-day case-fatality rates between 1993-1994 and 1997-1998 in men. Analogous but not statistically significant changes are reported for women. Conclusions. In the Brianza MONICA population in the second half of the 1990s, coronary event death rates continued to decrease. In contrast with trends observed in previous years, the prominent quote of the reduction is attributable to case-fatality rates in the acute phase