Independent ECG indicators of adverse outcome risk in the asymptomatic, at low risk Russian elderly working-aged population

Abstract

Objective. To identify independent electrocardiographic risk markers associated with all-cause and cardiovascular mortality, as well as the composite endpoint within a SCORE low-risk cohort of older working-age individuals in Russia. Materials and methods. The symptom-free cohort comprised older working-age participants (aged 40 to 64) selected from the random populations of nine regions participating in the ESSE-RF study. A total of 6.407 individuals (27.7% male) were included, all of whom had no prior history of myocardial infarction, stroke, coronary heart disease, or type 2 diabetes mellitus. Each participant had a low cardiovascular risk as determined by the SCORE scale. The study assessed the risk of both all-cause mortality (OCM) and cardiovascular mortality (CVM), as well as a composite endpoint (CEP) that included CVM cases or new incidences of myocardial infarction or stroke. The median follow-up duration was 11.6 years. Electrocardiograms (ECGs) at rest were analyzed in the standardized manner by the Minnesota Code. One-factor logistic regression was employed to identify predictive ECG metrics. Multifactorial stepwise regression was utilized to select independent high-risk ECG metrics, after excluding collinear (codependent) variables (VIF>5) from the analysis. The statistical calculations were adjusted for age and sex. Results. The analysis identified independent ECG metrics linked to adverse outcomes in the studied cohort, specifically rhythm and conduction disorders (such as complete left bundle branch block and atrial fibrillation), as well as changes in the STT period, characterized as «major ST disorders» and «minor STT disorders,» and signs of myocardial ischemia in the absence of left ventricular hypertrophy. The developed ECG models indicated that the OCM risk or CVM risk was doubled, and the CEP risk was 3.7 times higher than in the cohort without these ECG abnormalities. Within the analyzed cohort, there were identified 3—8% of individuals with increased adverse outcome risk using these ECG models. Conclusions. This study demonstrated a high predictive capability of electrocardiography in a Russian cohort of older working-age individuals with low cardiovascular risk according to the SCORE scale. The developed models are effective for predicting all-cause and cardiovascular mortality as well as the composite endpoint in the medium term. These findings provide valuable insights that can improve traditional methods of risk assessment for symptom-free populations.