A Cross-Sectional Analysis of Cardiovascular Disease in the Hemophilia Population

Introduction: Cardiovascular disease (CVD) is a disease of aging. While men with hemophilia were initially thought to be protected from CVD, it is now clear that atherothrombotic events do occur. The objective of this study is to determine the prevalence of CVD and CV risk factors among older men with moderate and severe hemophilia.

Methods: A U.S. national cross-sectional study began enrollment in 10/2012. Inclusion criteria are men with moderate or severe congenital hemophilia A or B (FVIII or IX level ≤ 5%), age 54-73. Men with an additional bleeding disorder (besides liver dysfunction) were excluded. After obtaining informed consent, CV risk factors, medications, and history of thrombotic events were obtained from patient interview and chart review. A fasting blood sample was assayed centrally.

Results: As of 8/1/2014, 160/200 planned subjects were recruited and interim analysis on 126 subjects from 18 U.S. Hemophilia Treatment Centers is presented here. The majority were white (109; 86.9%) or African American (15; 11.5%). Mean age was 62 years (SD: 5; range: 54-74). Most used factor on demand, with only 34.1% (43/126) on prophylaxis, defined as ≥2 doses of FVIII or ≥ 1 dose FIX/week. Five (4.0%) had a current inhibitor. Viral infection was common; 68.3% currently had hepatitis C, and 25% HIV.

Hypertension (HTN) was reported in 65.6% of subjects, 37.3% dyslipidemia and 24.6% diabetes (DM); 44.5% had ever smoked, 56.3% denied engaging in at least moderate physical activity and 43.7% had a family history of CVD. Average BMI was 28 kg/m² (29.4% obese) and waist circumference 97 cm. Fasting blood work showed an abnormally elevated: creatinine in 27.6% subjects (mean 1.09 mg/dl, SD 0.5), CRP in 6.3% (4.15 mg/L, 10.6), total cholesterol in 18.1% (169.49 mg/dl, 35.8), triglycerides in 25.2% (122.10 mg/dl, 58.2), LDL in 19.7% (102.27 mg/dl, 32.3); and low HDL in 45.7% (42.80 mg/dl, 12.2).

Ten subjects (7.9%) reported prior angina; 7 (5.6%) atrial fibrillation/flutter; 3 (2.4%) leg deep venous thrombosis; 2 (1.6%) myocardial infarction (MI), transient ischemic event (TIA), or pulmonary emboli; and 1 (0.8%) coronary artery angioplasty, stent placement, CABG, or peripheral arterial angioplasty.

In total, 11 subjects had CVD (defined as angina, MI, TIA, or ischemic or embolic stroke), a prevalence rate of 8.7%. This is significantly lower than the reported prevalence of 23% CVD in similar aged men without hemophilia in the longitudinal ARIC cohort (p-value <0.001). The qualifying diagnoses in our cohort included angina, MI and TIA. None of the men with CVD were on antiplatelet or anticoagulant medications.

Due to the small number of events, individual CV risk factors thus far did not achieve statistical significance in predicting CVD. Compared to never smokers, ever smokers had an odds ratio (OR) of 3.7 (95% CI: 0.9-14.8) of CVD. For HTN, dyslipidemia, and DM, the OR (95% CI) of CVD were 2.5 (0.5-12.1), 2.2 (0.6-7.5), and 1.9 (0.5-6.8), respectively. Positive family history (OR 2.4 (0.7-8.8)) and low-level of physical activity (1.4 (0.4-5.0)) also suggested some association with increased CVD risk. Obese BMI and large waist circumference were not significant.

Men using prophylaxis appeared less likely to have CVD (1/43, 2.3%) than men not on prophylaxis (10/83, 12.1%), OR 0.2 (0.02-1.4), although the difference was not statistically significant. HIV+ men (1/32, 3.1%) were also less likely to have CVD compared to non-HIV+ men (10/92, 10.9%), OR 0.3 (0.2-10.9), but not significantly so.

Lastly we investigated the role of anti-HTN (used in 36.5% of all subjects), cholesterol lowering (16.7%), and DM medications (10.3%) in reducing CVD. Not taking anti-HTN, cholesterol or DM medications non-significantly increased CVD risk with an OR in all subjects of 1.5, 3.3, or 3.9 respectively.

Conclusions: In this interim analysis of an ongoing national cross-sectional study, older men with moderate to severe hemophilia commonly report risk factors for CVD, including HTN (65.6%), dyslipidemia (37.3%) and renal insufficiency (27.6%). Despite this, the prevalence of reported CVD is low at 8.7%, suggesting that men with hemophilia may be protected from forming pathogenic thrombi. More data is needed to determine if the approach to prophylaxis or other therapies should be altered in this population. We plan to formally compare the prevalence of CVD and CV risk factors with similarly aged men in the ARIC database once enrollment is complete.