Reclassification of ischemic heart disease epidemiological criteria

Criteria for the epidemiological diagnosis of ischemic heart disease (IHD) determine the prevalence of the disease and allow to form approaches to prevention and treatment. Objective. To assess the epidemiological criteria of IHD based on their associations with mortality from cardiovascular diseases, non-fatal myocardial infarction (MI) or non-fatal cerebral stroke. Material and methods. According to the Minnesota code, 13 745 electrocardiography (ECG) results of a representative sample of the population aged 25—64 years in 10 regions —participants of the ESSE-RF study were analyzed. The initial classification of ECG-patterns was developed by experts of lipid clinics’ study (1988). The combined endpoint (CEP), including death from cardiovascular diseases or non-fatal cases of MI and cerebral stroke, has been monitored for 9.5 years. Statistical analysis was performed using the R 4.1 software. Each of the tested hypotheses was rejected at a significance level of p<0.05. When comparing several groups, the Holm-Bonferroni correction was considered. Results. Categories of IHD were systematized according to the occurrence of CEP in the course of prospective observation in choice with priority and were divided into three groups by the severity of the CEP prognosis. «Determined IHD» group included categories: «History of MI», «Angina pectoris in persons with ischemic changes of ECG», «Rhythm and conduction disorders» and «Determined MI»; «Possible IHD» group — «Myocardial ischemia with myocardial hypertrophy» and «Myocardial ischemia without myocardial hypertrophy», «Possible MI», «Angina pectoris» and «Possible ischemia»; «No IHD» group — «Different ECG-changes» and «No changes on ECG». The Cox model, adjusted for sex, age and region, confirmed the correctness of division. The relative risk of CEP occurrence amounted to 3.53 (2.84—4.38) for the «Determined IHD» group, 1.62 (1.33—1.99) — for the «Possible IHD» group with the «No IHD» reference value; the proportion of persons in the corresponding groups was 4.4, 15.1 and 80.5%. Conclusion. A modified classification of ischemic heart disease has been proposed based on the prospective estimation of the combined endpoint incidence.