OBJECTIVE  To analyze the association between ABO blood group and hospital-acquired infections （HAIs） in elderly patients, and to provide a reference for early identification of high-risk populations.

METHODS  A retrospective study was conducted on elderly patients （≥60 years） admitted to Quanzhou First Hospital Affiliated to Fujian Medical University from Jan. 2023 to Dec. 2024. Propensity score matching was applied to balance the HAI and non-HAI groups, followed by logistic regression analysis to explore the association between ABO blood group and HAI risk.

RESULTS  Among elderly patients with HAIs, blood type O was the most prevalent, while AB was the least common. Compared with blood type A, type B was associated with a higher risk of HAI （OR=1.518）. The risk of urinary tract infection in patients with blood type B was 4.083 times that of those with type A. Klebsiella pneumoniae-associated HAIs were significantly associated with blood types B （OR=2.588） and O （OR=2.762）.

CONCLUSIONS  ABO blood group is closely linked to HAI risk in elderly patients and may serve as a risk assessment factor. The underlying mechanisms require further investigation.