Time trends of myocardial infarction 28-day case-fatality in the 1990s: is there a contribution from different changes among socioeconomic classes?
OBJECTIVE
Almost two-thirds of the coronary death rate decrease in the northern Italian Brianza MONICA male population, between 1993-4 and 1997-8, are attributable to a reduction in 28-day myocardial infarction (MI) case-fatality. The present paper investigates the factors associated with MI case-fatality decrease and in particular the role of socio-occupational classes (SOCs).


METHODS
Standardised information on acute coronary care and intervention before and during the hospitalisation was collected for all coronary events (n = 1817) registered in 1993-4 and in 1997-8 among 35-64-year-old male residents in Brianza. Deaths within 28 days after MI were carefully investigated. Five SOCs were defined adopting the Erikson-Goldthorpe-Portocarero method. Differences in 28-day MI case-fatality and in acute phase intervention and treatment over time and among SOCs in each period were assessed.


RESULTS
28-day MI case-fatality reduction (27.2%) can be mainly attributed to a decreased proportion of MI events that were fatal before reaching the hospital. In the lower SOCs significant changes in MI case-fatality were detected between 1993-4 and 1997-8. Differences in acute phase intervention and treatment between the periods were observed. SOC differences both in prevalence of out-of-hospital cardiac arrest and in the pre-hospital qualified intervention score were detected in the first period only.


CONCLUSIONS
In the study population MI case-fatality reduction can be mainly attributed to a more effective and prompt management before hospitalisation and to an improvement in acute treatment during hospitalisation. This enhancement is made available to the whole population overtaking social differences.
Centro di Studio e Ricerca sulla Patologia Cronico-Degenerativanegli Ambienti di Lavoro, Dipartimento di Medicina Clinica, Prevenzione e Biotecnologie Sanitarie, Università degli Studidi Milano-Bicocca, Monza, Italy.
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Ferrario
D000328:Adult; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality* / Q000628:therapy; D012042:Registries; D012307:Risk Factors; D012923:Social Class; D013997:Time Factors; D055815:Young Adult