Photo by Daniel Gay
Blood in bags and vials
PARIS—Having a blood type other than O is associated with a higher risk of heart attack, according to a meta-analysis.
“It has been suggested that people with non-O blood groups (A, B, AB) are at higher risk for heart attacks and overall cardiovascular mortality, but this suggestion comes from case-control studies, which have a low level of evidence,” said Tessa Kole, a student at the University Medical Centre Groningen in the Netherlands.
Therefore, Kole and her fellow investigators conducted a meta-analysis of prospective studies reporting on blood groups and incident cardiovascular events.
The team presented their findings at Heart Failure 2017 and the 4th World Congress on Acute Heart Failure (abstract 697).
The study included 1,362,569 subjects from 11 prospective cohorts, described in 9 articles. There were a total of 23,154 cardiovascular events.
The investigators analyzed the association between blood group and all coronary events, combined cardiovascular events, and fatal coronary events.
The analysis of all coronary events included 771,113 subjects with a non-O blood group and 519,743 with an O blood group, of whom 11,437 (1.5%) and 7220 (1.4%), respectively, suffered a coronary event.
The odds ratio (OR) for all coronary events was significantly higher in subjects with a non-O blood group, at 1.09 (95% confidence interval [CI], 1.06-1.13, P<0.00001).
The analysis of combined cardiovascular events included 708,276 subjects with a non-O blood group and 476,868 with an O blood group, of whom 17,449 (2.5%) and 10,916 (2.3%), respectively, had an event.
The OR for combined cardiovascular events was significantly higher in subjects with non-O blood groups, at 1.09 (95% CI, 1.06-1.11, P=0.006).
The analysis of fatal coronary events did not show a significant difference between people with O and non-O blood groups. The OR was 1.00 (95% CI, 0.85-1.18, P=0.98).
“We demonstrate that having a non-O blood group is associated with a 9% increased risk of coronary events and a 9% increased risk of cardiovascular events, especially myocardial infarction,” Kole said.
“More research is needed to identify the cause of the apparent increased cardiovascular risk in people with a non-O blood group. Obtaining more information about risk in each non-O blood group (A, B, and AB) might provide further explanations of the causes.”
“In future, blood group should be considered in risk assessment for cardiovascular prevention, together with cholesterol, age, sex, and systolic blood pressure. It could be that people with an A blood group should have a lower treatment threshold for dyslipidemia or hypertension, for example. We need further studies to validate if the excess cardiovascular risk in non-O blood group carriers may be amenable to treatment.”
