TRENDS IN MORTALITY, INCIDENCE AND CASE-FATALITY OF ISCHEMIC-HEART-DISEASE IN DENMARK, 1982-1992

Background. In Denmark, as in many other Western countries, a decline in mortality from ischaemic heart disease (IHD) has been observed. The present study assesses whether the decline in IHD mortality is due to a decrease in incidence and/or case-fatality, and whether parallel ch anges occurred in the various manifestations of IHD requiring hospital ization. Methods. The National Patient Register of hospital discharges and the Causes-of-Death Register were linked and all cases of first a dmission for IHD including AMI and fatal first manifestation of IHD si nce 1977 in the entire Danish population were identified. Cases of AMI and IHD were considered as incident cases if no admission for these d iagnoses had occurred during the preceding 5 years. Sex-specific, age- standardized annual mortality, incidence and case-fatality rates of AM I (ICD8 code 410). narrowly defined IHD (NIHD, ICD8 codes 410-4) and b roadly defined IHD (BIHD, ICD8 codes 410-4, 427 and 795-6) were calcul ated for the period 1982-1992. Results. During the entire period the a ge-standardized mortality of AMI, NIHD and BIHD decreased in both men and women. The incidence of AMI and NIHD decreased, while the incidenc e of BIHD remained constant. Case fatality of AMI decreased in both me n and women, while case fatality of NIHD and BIHD decreased in men and in women aged 0-64 years only. Conclusion. The declining mortality fr om IHD in Denmark may be partly due to declining incidence as well as declining case fatality, but changes in disease manifestation or diagn ostic drift may also contribute because more broadly defined diagnosti c groups showed less or no decline in incidence.