Investigation and intervention post myocardial infarction in Scotland 1989-94. Multivariate analysis of the influence of age, sex, deprivation, health authority and year of admission
Findlay IN., McLeod M., Juszczak E., Cunningham AD.
There has been publication of conflicting evidence regarding gender and social class bias in cardiological practice. Part of this may be due to using a clinical diagnosis of angina or death certification of myocardial infarction as the marker for "need" as these are not synonymous with coronary heart disease (CHD). To overcome this we used an objective marker of CHD - discharge from hospital with the primary diagnosis of acute myocardial infarction (AMI-ICD9 code 410) as the basis of "need" and from the Scottish linked database 1989-1995 examined the rates of coronary angiography (CA), angioplasty (PTCA) and bypass surgery (CABG) in the year following discharge with AMI. In 1989-93 there were 34909 males (mean age 65) and 25486 females (mean age 72) first emergency admissions with AMI. Female admissions exceeded males after the age of 74 which was the upper limit of age used in this analysis. The odds ratios (O.R.) for the crude rates of CA and CABG but not PTCA were higher in men than women for each year (1.5 and 1.8 respectively). But in those aged <55 crude rates of CA and PTCA but not CABG were higher in women than in men. In multivariate analysis, in comparison with the Scottish average, the 4 Health Authorities with access to CA showed rates of CA ranging from .1.4-3.0 vs the remainder 0.6-1.6 and for PTCA 0.9-3.0 vs 0.6-1.8 and for CABG 0.8-1.5 vs 0.6-1.4. When comparing rates for male and female, multivariate analysis showed an increase in men in CA of 1.3 (1.2-1.4 95%CI) and CABG 1.5 (1.3-1.8 95%CI) but not PTCA 0.8 (P=NS). The lowest deprivation group showed an increase rate of CA (1.5), and CABG (1.9) but not PTCA (1.1) compared with the most deprived group. The most significant effect was seen with age. When comparing age group 35-44 vs 65-74 the O.R. for CA, PTCA and CABG was 9.3, 9.8 and 3.2 respectively. From 1989 to 1993 the increase in CA, PTCA and CABG was 1.7, 2.1 and 1.9 respectively. In conclusion even post AMI there remains an unaccounted difference in intervention related to sex and social class though PTCA was not affected by this.