Declining Coronary Heart Disease Mortality in Iceland: Contribution by Incidence, Recurrence and Case Fatality Rate

OBJECTIVE: To analyse to what extent the recent decline in coronary heart disease mortality in Iceland is due to changes in incidence, recurrence and case fatality rates. DESIGN: A countrywide registration of myocardial infarction (MI) in people aged 25-74 was performed in Iceland during 1981-1999 according to the MONICA protocol. Possible cases were found by review of all hospital discharge records, autopsy records and death certificates. RESULTS: MI death rate declined by 63% in males and 51% in females, most in the youngest age groups in men (86%) and least in the oldest (49%). In women there was not a significant difference in age groups. Overall the age-adjusted reduction in MI death rate was 55.4% in both sexes combined; of this 23.1% was due to incidence reduction, 22.8% to recurrence reduction and 11.6% to case fatality reduction. In the youngest age groups the decline in incidence contributed most to the decline in MI death rate (62% in men and 71% in women), but thereafter the decline in case fatality in men. In the older age groups decline in recurrence rate has greater weight. CONCLUSION: The recent decline in MI mortality under the age of 75 years in Iceland is due to reduction in incidence and recurrence rate by about 40% each and to reduction in case fatality by 20%.