The supplementary online content includes several tables and figures related to a study on routine electrocardiogram (ECG) screening and cardiovascular disease (CVD) events in adults. eTable 1 describes the classification system of ECG abnormalities. eTable 2 outlines ECG categorizations in 2015 and 2016. eTable 3 presents a sensitivity analysis that additionally adjusts for medication use information. eTable 4 provides hazard ratios for overall death and CVD admission according to ECG status. eTable 5 shows the proportion of follow-up ECGs in individuals with ECGs in 2016. eTable 6 and eTable 7 detail the association of minor and major ECG abnormalities with the composite endpoint. eTable 8 reports the number of echocardiogram and catheterization procedures within one year after the baseline ECG. eFigure 1 includes Schoenfeld residual plots for different population groups. eFigure 2 compares the risks of the composite endpoint (overall death and CVD admission) across subgroups based on baseline CVD risk and ECG status. eFigure 3 compares the risks of new major ECG abnormalities across subgroups based on baseline CVD risk. The hazard ratios (HRs) for the endpoints were adjusted for various factors including age, sex, body mass index, comorbidities, blood pressure, glucose, lipid levels, and estimated glomerular filtration rate. The study provides detailed statistical analyses and additional information to support the main findings of the research.The supplementary online content includes several tables and figures related to a study on routine electrocardiogram (ECG) screening and cardiovascular disease (CVD) events in adults. eTable 1 describes the classification system of ECG abnormalities. eTable 2 outlines ECG categorizations in 2015 and 2016. eTable 3 presents a sensitivity analysis that additionally adjusts for medication use information. eTable 4 provides hazard ratios for overall death and CVD admission according to ECG status. eTable 5 shows the proportion of follow-up ECGs in individuals with ECGs in 2016. eTable 6 and eTable 7 detail the association of minor and major ECG abnormalities with the composite endpoint. eTable 8 reports the number of echocardiogram and catheterization procedures within one year after the baseline ECG. eFigure 1 includes Schoenfeld residual plots for different population groups. eFigure 2 compares the risks of the composite endpoint (overall death and CVD admission) across subgroups based on baseline CVD risk and ECG status. eFigure 3 compares the risks of new major ECG abnormalities across subgroups based on baseline CVD risk. The hazard ratios (HRs) for the endpoints were adjusted for various factors including age, sex, body mass index, comorbidities, blood pressure, glucose, lipid levels, and estimated glomerular filtration rate. The study provides detailed statistical analyses and additional information to support the main findings of the research.