Objective To investigate the predictive value of serum inflammatory indicators C-reactive protein (CRP) and procalcitonin (PCT) combined with neutrophil/lymphocyte ratio (NLR) in predicting major adverse cardiovascular events (MACE) in the elderly (≥60 years old) diabetic Han Chinese infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant during hospitalization. Methods All 1038 consecutive elderly patients hospitalized in the Affiliated Hospital of Xuzhou Medical University due to infection with the Omicron variant were enrolled from December 2022 to February 2023, and 94 were excluded, leaving 944 for final analysis. Patients were divided into diabetes mellitus (DM) group (n=189) and non-DM group (n=755) according to the presence of diabetes mellitus. Based on occurrence of MACE during hospitalization, they were divided into MACE group (n=89) and non-MACE group (n=100). SPSS statistics 25.0 was used for data analysis. Based on the data type, student′s t test, Mann-Whitney U test, or Chi-square test was employed for intergroup comparison. Multivariate logistic regression analysis and receiver operating charac-teristic (ROC) curve were used to analyze the influence of serum inflammatory indicators (PCT, CRP and NLR) and their predictive value for MACE in the elderly diabetic patients during hospitalization. Results Of the 944 elderly patients, 244 (25.8%) had MACE during hospitalization. Diabetic patients had a higher rate of MACE than non-diabetic patients (47.1% vs 20.5%), and the difference was statistically significant. Among diabetic patients, compared with the non-MACE group, the MACE group were older, had higher fasting blood glucose, had a significant higher proportion of patients with a history of cerebral infarction, higher levels of all three serum inflammatory indexes (PCT, CRP, and NLR), and a higher white blood cell (WBC) count, the differences being statistically significant (P<0.05). Multivariate logistic regression analysis showed that age (OR=1.062, 95%CI 1.009-1.118; P=0.021), PCT (OR=1.614, 95%CI 1.340-1.943; P<0.001), CRP (OR=1.008, 95%CI 1.000-1.016; P=0.038), and NLR (OR=1.261, 95%CI 1.103-1.441; P=0.001) were independent predictors of MACE in elderly diabetic patients infected with the Omicron variant during hospitalization. The ROC curve and Delong test indicated that the PCT+CRP+NLR model had a better clinical predictive value for MACE in the patients during hospitalization than single inflammatory indicators. Conclusion Serum inflammatory indicators PCT, CRP, and NLR have good predictive power for MACEs in the elderly diabetic patients infected with the Omicron variant during hospitalization.