Certification of death from ischaemic heart disease in Belfast.

All death certificates over a one-year period (20 July 1981 to 19 July 1982) for residents of Belfast were examined in order to ascertain those due to ischaemic heart disease. Some 1654 were included for further investigation of which 1288 (78%) were coded by ICD Nos 410-414 (9th revision). Additional data were obtained from hospital records, ECGs, cardiac enzyme measurements, post mortems, general practitioners and from relatives of the deceased. Some 108 deaths coded by 410-414 and 223 deaths coded by other rubrics were eventually excluded. For people aged less than 70 years the net effect of excluding these deaths and including some coded under rubrics other than 410-414 was very small representing a change from 498 to 496 deaths (-0.4%). For people aged 70 years and above the net effect also was small, namely an increase from 790 to 827 (+4.4%). We conclude that the total number of deaths recorded as being due to IHD in Belfast was reasonably accurate. While 76% of deaths registered under ICD Nos 410-414 had been coded by ICD No 410 (acute myocardial infarction) only 19% of all deaths due to IHD could be classified as definite myocardial infarction using World Health Organization criteria.