Papers - 22 February 1997

Objective: To investigate the effect of socioeconomic group (with reference to age and sex) on the rate of, course of, and survival after coronary events. Design: Community coronary event register from 1985 to 1991. Setting: City of Glasgow north of the River Clyde, population 196 000. Subjects: 3991 men and 1551 women aged 25-64 years on the Glasgow MONICA coronary event register with definite or fatal possible or unclassifiable events according to the criteria of the World Health Organisation’s MONICA project (monitoring trends and determinants in cardiovascular disease). Main outcome measures: Rate of coronary events; proportion of subjects reaching hospital alive; case fatality in admitted patients and in community overall. Results: Event rates increased with age for both sexes and were greater in men than women at all ages. The rate increased 1.7-fold in men and 2.4-fold in women from the least (Q1) to the most (Q4) deprived socioeconomic quarter. The socioeconomic gradient decreased with age and was steeper for women than men. The proportion treated in hospital (66%) decreased with age, was greater in women than men, and decreased in both sexes with increasing deprivation (age standardised odds ratio 0.82 for Q4 v Q1) Case fatality in hospital (20%) increased with age, was greater for women than men when age was standardised, and showed no strong socioeconomic pattern. Overall case fatality in the community (50%) increased with age, was similar between the sexes, and increased from Q1 to Q4 (age standardised odds ratio 1.12 in men, 1.18 in women). Conclusions: Socioeconomic group affects not only death rates from myocardial infarction but also event rates and chance of admission. This should be taken into account when different groups of patients are compared. Because social deprivation is associated with so many more deaths outside hospital, primary and secondary prevention are more likely than acute hospital care to reduce the socioeconomic variation in mortality. Introduction Age, sex, and socioeconomic group all affect a population’s mortality from coronary heart disease. Population registers have been used to document the effect of age and sex on event rates and case fatality in a community. Studies limited to patients admitted to coronary care units or hospital wards 7-10 or to those in drug trials related to myocardial infarction 12 have reported the relation between case fatality in hospital, age, and sex. Social class may be related to event rates, delay in seeking medical care during myocardial infarction, 19 and case fatality in hospital. We investigated the relation of socioeconomic group to four things—event rates, the proportion of people reaching hospital alive, mortality in hospital, and overall case fatality—in men and women who had fatal and non-fatal consecutive events over a period of seven years in a defined geographical population. Wilhelmsen and Rosengren recently showed the surprising lack of data on these things. Subjects and methods The Glasgow MONICA coronary event register comprises all cases of myocardial infarction and coronary death occurring in men and women aged 25-64 years resident in north Glasgow. The methods of ascertainment and investigation have been described previously. Ascertainment derives from hospital discharge data, the registrar general, and other, minor, sources. We validated the events ascertained using the criteria of the World Health Organisation’s MONICA (monitoring trends and determinants in cardiovascular disease) project, and these depend on symptoms, electrocardiographic evidence, cardiac enzyme concentrations, and necropsy reports. Diagnostic information was gathered from many sources, including hospital case notes, general practitioners, and police reports to the procurators fiscal (the medicolegal authority in Scotland). Survival was determined at 28 days from the onset of the event. For this analysis we used all events classified as definite and all fatal events classified as possible and unclassifiable. This definition excludes See editorial by Haines and Smith and pp 547, 553, 558, 591 MONICA Project, Royal Infirmary, Glasgow G31 2ER Caroline Morrison, consultant in public health medicine Wilma Leslie, senior research nurse Department of Applied Statistics, PO Box 240, University of Reading, Reading RG6 6FN Mark Woodward, senior lecturer in statistical epidemiology Cardiovascular Epidemiology Unit, Ninewells Hospital and Medical School, Dundee DD1 9SY Hugh Tunstall-Pedoe, professor Correspondence to: Dr Morrison.