Hypertension or high blood pressure is one of the age-related conditions in hemophilia that has not been explored very thoroughly. Historically, before the advent of factor products, people with hemophilia often did not survive childhood. Treatment with clotting factors significantly increased life expectancy, but then the AIDS crisis came along and devastated much of the hemophilia population, so they never reached old age. It is only more recently, now that life expectancy is approximately that of the general population, that it has become possible to study aging in people with hemophilia. High blood pressure is a concern because it is associated with heart disease, stroke, eye disease and kidney disease. It is also one of the major risk factors in intracranial hemorrhage (ICH), which is 20 to 50 times more common in people with hemophilia than in the general population and can be fatal.
Hemophilia patients tend to have higher blood pressures for unknown reasons. A recent study from three U.S. hemophilia treatment centers (Barnes et al, Int J Hypertension, Epub 2014201, Nov 14, 2016) has shown that the usual cardiovascular risk factors do not explain the greater incidence of high blood pressure in people with hemophilia compared to the general population. The researchers compared 469 male hemophilia patients, both As and Bs, to age-matched male controls from the National Health and Nutrition Examination Survey, a series of surveys to evaluate the health status of the U.S. population.
Risk factors for high blood pressure in the general population include age, obesity, cholesterol, kidney function, diabetes, smoking, hepatitis C virus infection (HCV) and race. The hemophilia patients in the study showed both higher systolic (top number) and diastolic pressures (bottom number) than the general population regardless of the risk factor examined, except HCV. HCV did appear to be a risk factor for the older age group (≥ 30 years), but it only explains part of the variation. Even comparing patients being treated with blood pressure medication, treated people with hemophilia had higher pressures. The hemophilia patients in the study actually had fewer risk factors than the controls: their weights and cholesterol were lower, they had better kidney function and they had lower rates of smoking and diabetes, yet their blood pressures were worse.
Note that this does not mean that people with hemophilia can ignore the risk factors. They will still affect their blood pressure. It’s just that there is apparently more going on for hemophilia patients than just those risk factors. Something else is also causing their blood pressures to increase.
One interesting clue from the study is that there is not as much of a drop from systolic to diastolic pressure in people with hemophilia as there is in the controls. This suggests a greater stiffness of the blood vessel walls, which may indicate vascular changes occurring in hemophilia. Other studies have also identified vascular abnormalities in people with hemophilia, but overall little is known. Another unexpected finding was that the youngest age group (< 30 years) of hemophilia patients had markedly higher blood pressures than their age-matched controls. This is a worrisome result that warrants further investigation.
This study has uncovered some significant information about high blood pressure and hemophilia, but much more remains to be learned. Meanwhile, all hemophilia patients, even younger ones, should pay attention to their blood pressure. High blood pressure is known as a silent killer because there are usually no apparent symptoms until it is too late. The only way to tell if you have high blood pressure is to measure it. Normal blood pressure is 120/80 when sitting quietly. If either or both numbers are much higher, you should consult your physician about possible treatment.