The prevalence of hypertension is higher in patients with hemophilia than in the general population, according to a nationwide study in Sweden with long-term follow-up.
The study, “Hypertension and cardiovascular diseases in Swedish persons with haemophilia — A longitudinal registry study,” appeared in the journal Thrombosis Research.
The outcomes and prevalence of cardiovascular diseases in people with hemophilia remain unclear, with prior studies reporting conflicting findings. Besides the lack of consistent associations with known risk factors for hypertension — such as cholesterol levels, kidney function, and smoking — the impact of blood-transmitted viral diseases (including HIV and hepatitis) on cardiovascular risk has also not been established in hemophilia patients.
Hemophilia patients in Sweden have been receiving prophylactic (preventive) treatment for decades, which, according to the scientists, may have both benefits (less bleeding) and drawbacks — higher protein deposition affecting kidney function — for cardiovascular diseases. However, no prospective studies have evaluated cardiovascular complications in Swedish patients from young age into adulthood.
Researchers in this study addressed this by taking advantage of the country’s National Patient Registry and using data from hemophilia treatment centers in Malmö, Stockholm, and Gothenburg.
Among 1,431 hemophilia patients (mean year of birth 1960; median follow-up of 44.3 years), the team identified 196 cases of hypertension (13.7%). Of the 7,150 individuals used as controls, 551 (7.7%) were found to be hypertensive.
To have an observation period of at least 30 years, the scientists then conducted a more restricted analysis in patients born in 1978 or earlier, which showed that 19.7% of the hemophilia patients and 11.2% of the controls had hypertension. This represented a 2.1 times higher risk in the group with hemophilia. The median age at hypertension diagnosis was 60 years in hemophilia patients and 57.2 years in the controls.
In a subgroup with long-term follow-up, 53 (15.1%) patients with non-severe hemophilia and 35 (18.2%) of those with severe disease were hypertensive, which also corresponded to a greater risk of hypertension than in controls.
Hemophilia patients with hepatitis but not HIV were at an even greater risk — 3.3. times higher — of experiencing hypertension. In contrast, the subgroup with non-severe hemophilia and without hepatitis or HIV was not more susceptible to having hypertension than the controls.
Hypertension was the cause of death of three (0.8%) of the 382 hemophilia patients who died during the study period. A similar percentage was found in the controls.
At 75 years of age or younger, angina pectoris — chest pain or discomfort due to coronary heart disease — occurred in 69 (4.8%) of the hemophilia patients and 311 (4.3%) of the controls, indicating no significant differences. However, among those without hepatitis or HIV, the risk for angina pectoris was significantly greater in the hemophilia group than in the controls.
Myocardial ischemia was diagnosed in 84 (5.9%) of the patients with hemophilia and 442 (6.2%) of the controls before age 75. Although this revealed a similar risk in the overall study population, the subgroup with non-severe hemophilia was more susceptible to having myocardial ischemia than the controls.
No significant differences were seen in the subgroup without blood-transmitted diseases; the number of cases of hemophilia patients with these infections was too small to perform additional statistical comparisons.
Myocardial ischemia was the cause of death in significantly more controls — 388 (28.7%) — than hemophilia patients (47, 12.3%).
“Our data support an increased prevalence of hypertension among persons with haemophilia,” the scientists wrote. “The prevalence of [cardiovascular diseases] seems to be similar to that of controls, but with lower mortality.”