ABO Blood Types and Mortality in Patients Undergoing Hemodialysis.

Abstract

ABO blood types have been linked to cardiovascular and noncardiovascular mortality in nondialysis populations, but whether these associations extend to patients undergoing hemodialysis remains unclear. This study aimed to examine the associations between ABO blood types and all-cause, cardiovascular, and noncardiovascular mortality in these patients. This multicenter prospective cohort study included 1671 patients undergoing hemodialysis from 17 dialysis facilities in Japan, followed for up to 5 years. ABO blood type was obtained from medical records. Outcomes were all-cause, cardiovascular, and noncardiovascular mortality. ABO blood type distribution was A: 650 (38.9%), B: 358 (21.4%), AB: 176 (10.5%), and O: 487 (29.1%). During 5 years of follow-up, 464 deaths occurred, including 278 cardiovascular and 186 noncardiovascular. In multivariable Cox regression models, blood type A, but not blood types B or AB, was associated with a significantly lower risk of all-cause mortality compared with blood type O (hazard ratio [HR]: 0.780; 95% confidence interval [CI]: 0.619-0.981; P = 0.034). In Fine-Gray subdistribution models, blood type A, but not blood types B or AB, was also associated with a lower risk of cardiovascular mortality. Exploratory analyses comparing blood type A with non-A blood types for cardiovascular mortality yielded similar results, with consistent findings across subgroups and sensitivity analyses. In contrast, no significant association was observed between ABO blood type and noncardiovascular mortality. ABO blood type may be associated with all-cause and cardiovascular mortality in patients undergoing hemodialysis, with lower risks observed in those with blood type A.