Predicting In-hospital Mortality Using Elixhauser Comorbidity in Patients Underwent Single and Multiple Coronary Artery Bypass Surgery

Background Coronary Artery Bypass Graft (CABG) surgery is a high-risk surgery (mortality rate between 2-4 percent) performed in patients with ischemic heart disease (IHD). Cardiovascular diseases are strongly associated with comorbidities. This study aimed to assess the prediction of in-hospital mortality by comorbidities in patients who underwent single, double, triple, or quadruple and more CABG. Methods The National Inpatient Sample (NIS) database was used to extract patients who received 1, 2, 3, or 4+ CABG between the last quarter of 2015 and 2020. Best-fit model by logistic regressions was used to predict in-hospital mortality by Elixhauser Comorbidity Index (ECI). Moreover, age was adjusted in ECI prediction. Results In-hospital mortality was best predicted by ECI in patients who underwent 3 CABG ( c -statistic = 0.6325, 95% CI = 0.6151-0.6499), followed by 4+ CABG ( c -statistic = 0.6308, 95% CI = 0.5997-0.6620), 1 CABG ( c -statistic = 0.6194, 95% CI = 0.6108-0.6281), and 2 CABG ( c -statistic = 0.6193, 95% CI = 0.6069-0.6317). After adjusting for age, ECI adequately predicted in-hospital mortality in 4+ CABG ( c -statistic = 0.7196, 95% CI = 0.6916-0.7477) and 3 CABG ( c -statistic = 0.6937, 95% CI = 0.6774-0.7101). The predictive power for age-adjusted ECI was comparable in 1 CABG ( c -statistic = 0.6674, 95% CI = 0.6594-0.6755) and 2 CABG ( c -statistic = 0.6664, 95% CI = 0.6549-0.6780). Conclusions This study showed that ECI alone was a moderate ( c -statistic 0.6-0.7) predictor of in-hospital mortality in all CABG. Age-adjusted ECI could effectively predict in-hospital mortality, especially in patients who underwent 3 and 4+ CABG.