Abstract: OBJECTIVE To analyze the prevalence of health care-associated carbapenem-resistant Enterobacteriaceae infection (CRE) infection among the elderly patients with different major diagnostic categories (MDCs) in intensive care unit (ICU) and evaluate the economic burden and the expenditure of healthcare insurance fund based on China Healthcare Security Diagnosis Related Groups (CHS-DRG). METHODS The MDCs of CRE infection were collected from the elderly patients of 14 ICUs in The First People's Hospital of Jintan and The Second People's Hospital of Changzhou by health care-associated infections (HAIs) information system from 2021 to 2024. The influence of the CRE infection on the length of hospital stay, self-payment amount, consumption of healthcare insurance fund of the patients with different MDCs were analyzed by means of generalized linear models. RESULTS The patients with HAIs of CRE were primarily distributed across MDCA, MDCB, and MDCE. Compared with the patients infected with carbapenem-sensitive Enterobacteriaceae (CSE), the mean length of hospital stay increased by 14.82 days (P=0.007), the average self-payment expenses increased by 27 230.52 yuan(P<0.001), and average healthcare insurance fund increased by 75 873.62 yuan (P< 0.001). Among the patients with MDCB and MDCF, the average healthcare fund expenses of the CRE group were respectively 131 530.73 yuan (P=0.001)and 172 126.11 yuan(P=0.024) more than those of the CSE group. Among the elderly ICU patients with CRE infection, the average healthcare insurance expense of the patients with MDCB was 134 476.73 yuan(P=0.011) more than that of the patients with MDCE. CONCLUSIONS The CRE infection may increase the length of hospital stay, self-payment expenses, and expense of healthcare insurance fund, and it varies in the impact on the patients with different MDCs. It is necessary to formulate and implement differentiated infection control measures based on the MDC so as to control the transmission of CRE, ease the economic burden and reduce the expense of healthcare insurance fund.