MYOCARDIAL-INFARCTION AND CORONARY DEATHS IN THE WORLD-HEALTH-ORGANIZATION MONICA PROJECT - REGISTRATION PROCEDURES, EVENT RATES, AND CASE-FATALITY RATES IN 38 POPULATIONS FROM 21 COUNTRIES IN 4 CONTINENTS

Background The WHO MONICA Project is a 10-year study that monitors dea ths due to coronary heart disease (CHD), acute myocardial infarction, coronary care, and risk factors in men and women aged 35 to 64 years i n defined communities. This analysis of methods and results of coronar y event registration in 1985 through 1987 provides data on the relatio n between CHD morbidity and mortality. Methods and Results Fatal and n onfatal coronary events were monitored through population-based regist ers. Hospital cases were found by pursuing admissions (''hot pursuit'' ) or by retrospective analysis of discharges (''cold pursuit''). Avail ability of diagnostic data on identified nonfatal myocardial infarctio n was good. Information on fatal events (deaths occurring within 28 da ys) was limited and constrained in some populations by problems with a ccess to sources such as death certificates. Age-standardized annual e vent rates for the main diagnostic group in men aged 35 to 64 covered a 12-fold range from 915 per 100 000 for North Karelia, Finland, to 76 per 100 000 for Beijing, China. For women, rates covered an 8.5-fold range from 256 per 100 000 for Glasgow, UK, to 30 per 100 000 for Cata lonia, Spain. Twenty-eight-day case-fatality rates ranged from 37% to 81% for men (average, 48% to 49%), and from 31% to 91% for women (aver age, 54%). There was no significant correlation across populations for men between coronary event and case-fatality rates (r=-.04), the perc entages of coronary deaths known to have occurred within 1 hour of ons et (r=.08), or the percentages of known first events (r=-.23). Event a nd case-fatality rates for women correlated strongly with those for me n in the same populations (r=.85, r=.80). Case-fatality rates for wome n were not consistently higher than those for men. For women, there wa s a significant inverse correlation between event and case-fatality ra tes (r=-.33, P<.05), suggesting that nonfatal events were being missed where event rates were low. Rankings based on MONICA categories of fa tal events placed some middle- and low-mortality populations, such as the French, systematically higher than they would be based on official CHD mortality rates. However, rates for nonfatal myocardial infarctio n correlated quite well with the official mortality rates for CHD for the same populations. For men (age 35 to 64 years), approximately 1.5 (at low event rates) to 1 (at high event rates) episode of hospitalize d, nonfatal, definite myocardial infarction was registered for every d eath due to CHD. The problem in categorizing deaths due to CHD was the large proportion of deaths with no relevant clinical or autopsy infor mation. Unclassifiable deaths averaged 22% across the 38 populations b ut represented half of all registered deaths in 2 populations and a th ird or more of all deaths in 15 populations. Conclusions The WHO MONIC A Project, although designed to study longitudinal trends within popul ations, provides the opportunity for relating rates of validated CHD d eaths to nonfatal myocardial infarction across populations. There are major differences between populations in nonfatal as well as fatal cor onary event rates. They refute suggestions that high CHD mortality rat es are associated with high ease-fatality rates or a relative excess o f sudden deaths. The high proportion of CHD deaths for which no diagno stic information is available is a cause for concern.