The Impact of the Elixhauser Comorbidity Index on Length of Stay in Patients with Coronary Atherosclerotic Heart Disease

Objectives To investigate the impact of the Elixhauser Comorbidity Index (ECI) on length of stay (LOS) among patients with coronary atherosclerotic heart disease (CAD). Methods A retrospective analysis was conducted using CAD patient data from the Hubei Provincial Traditional Chinese Medicine Comprehensive Statistics Platform between December 2013 and June 2024. Data on demographics, comorbidities, and surgical status were collected. The comorbidity burden was assessed using the ECI as modified by Walraven et al. Factors associated with LOS were identified using the Kruskal-Wallis H test and Mann-Whitney U test. A Gamma regression model was constructed for multivariable analysis to identify independent factors influencing LOS, and a sensitivity analysis was performed to verify the robustness of the results. Results 22,626 CAD patients were included, with a median LOS of 9 (6,13) days. Univariate analysis showed statistically significant differences in LOS across age groups (Kruskal-Wallis H = 613.131, df = 3, < 0.001), mode of admission (Kruskal-Wallis H = 15.106, df = 2, P = 0.001), mode of discharge (Kruskal-Wallis H = 137.157, df = 2, < 0.001), surgical status (Mann-Whitney U = 16,470,870.000, Z = -7.989, < 0.001), treatment categories (Kruskal-Wallis H = 1510.879, df = 2, < 0.001), and ECI groups (Kruskal-Wallis H = 291.185, df = 3, < 0.001). Gamma regression analysis revealed that, after adjusting for confounding factors, ECI was an independent predictor of LOS (< 0.001). Patients with ECI scores of 1–3 (Exp(B) = 1.100, 95% CI = 1.064–1.138, < 0.001) and 4–8 (Exp(B) = 1.029, 95% CI = 1.003–1.055, = 0.026) had LOS prolonged by 10.0% and 2.9% respectively, while the ECI ≥ 9 group showed no statistical significance (Exp(B) = 1.009, 95% CI = 0.985–1.034, = 0.479). Sensitivity analysis revealed that after excluding patients with extremely long LOS, the ECI ≥ 9 group reached statistical significance (= 0.027), indicating that the impact of a high comorbidity burden on LOS became more evident after removing outlier interference. Conclusion ECI is an independent influencing factor for LOS in CAD patients. Clinical practice should emphasize individualized management of patients with a high comorbidity burden to shorten LOS and improve medical resource utilization efficiency.