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According to research published in Blood Advances, a lower-than-predicted incidence of cardiovascular disease (CVD) was found among patients with hemophilia, supporting the theory that hemophilia protects against CVD.
Investigators conducted a prospective, multicenter, observational study (ClinicalTrials.gov Identifier: NCT01303900) to describe the incidence of fatal and nonfatal CVD during 5 years of follow up in adult patients with hemophilia (aged >30 years) from The Netherlands and United Kingdom and compared the event rate with that predicted based on a general cardiovascular risk model (QRISK2-2011).
The primary endpoint was observed fatal and nonfatal CVD events after 5 years compared with predicted CVD events. The relation of CVD risk to severity of hemophilia and treatment form was also evaluated.
A total of 709 patients, with a mean age of 48±13.4 years, was included in the study. Most patients (96.9%) completed the 5 years of follow-up or reached an endpoint. The QRISK score could not be calculated for 108 patients (15.2%) at inclusion, and 22 patients (3.1%) were lost to follow-up.
A complete data set was available for 579 patients (81.6%; mean age, 46±11.7 years). Hemophilia severity was severe in 52.5%, moderate in 12.8%, and mild in 34.7% of patients. The average QRISK score was 2.0±5.42. Previous CVD and family history of coronary heart disease was reported in 1.6% and 33.0%, respectively.
The researchers observed fewer CVD events than predicted, 9 (1.7%) vs 24 (4.1%; relative risk [RR], 0.38; 95% CI, 0.18-0.80; P =.01), corresponding to an absolute risk reduction of 2.4%. Risk reduction was similar across hemophilia severity subgroups. The finding indicates that the QRISK predictor is not valid for people with hemophilia.
In people with severe hemophilia the RR was dependent on treatment modality, with those treated on demand (n=122) having the highest risk reduction (0 observed vs 5 predicted CVD events; RR, 0; P =.03). Among patients on prophylaxis therapy (n=182), 4 CVD events were observed, while 7 were predicted (RR, 0.57; 95% CI, 0.17-1.92; P =.27).
For the patients whom the QRISK score could not be calculated at inclusion (n=108 [15.2%]; primarily attributed to statin use [42.6%] and history of CVD [39.8%]), the CVD incidence was 11.1%.
“In hemophilia, a lower-than-predicted CVD incidence was found, supporting the theory that hemophilia protects against CVD,” the researchers concluded in their report. “However, events do occur, especially in people with a high risk for CVD.”
Limitations of the study included use of the use of the QRISK2-2011 score for the predicted outcome, no inclusion of modifiers (such as treatment for severe hypertension or severe dyslipidemia) in risk scores, and lack of consideration of socioeconomic status or other confounding factors. The researchers noted that future studies should include people with hemophilia and high risk of CVD.