Blood group systems based on red blood cell antigens are genetically determined 
and can identify patients at risk. Type non-O of the ABO blood group system has 
been associated with coronary artery disease, thrombosis, and a worse prognosis. 
The present study evaluated the distribution of blood group types in patients 
with heart failure (HF) and the impact on clinical outcome. We evaluated the ABO 
and Rhesus D antigen (RhD) blood types in a large cohort of chronic HF patients 
(n = 3,815). ABO blood type distribution in the HF population was not 
significantly different to that reported in the general national population (A 
40%, B 20%, AB 8%, and O 33%). The percentage of Rh-negative per blood type was 
also similar (A 10%, B 9%, AB 10%, and O 7%). Patients with type O were more 
likely to be hypertensive compared with non-O type. Mean follow-up was 
4.2 years. Overall survival during follow-up was 55%. Cox regression analysis 
after adjustment for significant predictors demonstrated that RhD-negative was 
associated with a worse prognosis in patients with ischemic cardiomyopathy (n = 
2,881, 76%): hazard ratio 1.26, 95% confidence interval 1.04 to 1.53, p = 0.02. 
Type non-O was also independently associated with a worse prognosis compared 
with type O in patients with non-ischemic cardiomyopathy: hazard ratio 1.32, 95% 
confidence interval 1.04 to 1.67, p = 0.02. In conclusion, blood group type 
distribution in HF patients are similar to the general population. RhD-negative 
is associated with a worse prognosis in patients with ischemic cardiomyopathy.