Decreased mortality of ischaemic heart disease among carriers of haemophilia

Background Coagulation plays an important part in ischaemic cardiovascular disease. Results of studies have shown that extremes in hypocoagulability protect against ischaemic cardiovascular disease. We have investigated overall mortality and death from cardiovascular causes in carriers of haemophilia, who in most cases have mildly decreased coagulability without clinical signs. Methods We followed-up a cohort of 1012 mothers of all known people with haemophilia in the Netherlands from birth to death, or the end-of-study date (41984 person years of follow-up). We obtained vital status and causes of death, if deceased, and compared overall and cause-specific mortality in our cohort with that in the general Dutch female population adjusted for age and calendar period by calculating the standardised mortality ratio (SMR). Findings Overall mortality was reduced by 22% (261 observed deaths, 333•74 expected; SMR 0•78 [95% CI 0•69-0•88]). Deaths from ischaemic heart disease were reduced by 36% (39 observed deaths, 60•53 expected; SMR 0•64 [0•47-0•88]). We did not note decreased mortality for cerebral stroke (ischaemic and haemorrhagic combined) (28 observed deaths, 36•82 expected; SMR 0•76 [0•53-1•10]). A separate analysis of these two types of stroke was not possible. Women in our cohort had an increased risk of death from extracranial haemorrhage (5 observed deaths, 0•18 expected; SMR 27•78 [8•49-58•18]); however, the number of deaths from this cause was much lower than that for ischaemic heart disease. Conclusion The results show that a mild decrease in coagulability has a protective effect against fatal ischaemic heart disease.