Blood Evident in Urine Linked to Hypertension in Patients with Family History
Blood visibly present in urine — called macroscopic hematuria — considerably increases the risk of hypertension in hemophilia patients with a family history of high blood pressure, and is not a “benign” condition for this patient group, a study reports.
The study, “Macroscopic hematuria as a risk factor for hypertension in ageing people with hemophilia and a family history of hypertension,” was published in the journal Medicine.
Hemophilia is caused by genetic deficiency in specific clotting factors, leading to spontaneous and frequent bleeds. In the last 30 years, studies have shown that these patients are more prone to develop hypertension than the general population.
Researchers believe that kidney bleeds and disease might explain the higher hypertension rates in these patients. Visible (macroscopic) or non-visible (microscopic) hematuria — the presence of blood or red blood cells in the urine — is a common issue in hemophilia.
Among the few studies to date that investigated a relationship between hematuria and hypertension, results are controversial. While some suggest that hypertension is more prevalent in those with kidney bleeds, others report no link between hematuria and hypertension.
Hypertension’s likelihood is well-known to be associated with genetic factors (family history), and such lifestyle or environmental factors as obesity, age, diabetes, and high salt and alcohol intake.
Researchers at the Oslo University Hospital, in Norway, and their colleagues looked for a link between hematuria and high blood pressure in a large group of people with hemophilia.
In total, their analysis covered 532 hemophilia patients with a median age of 52 (range 40–98). Most, 87%, of these people had hemophilia A, and 13% had hemophilia B. More than half (58%) had severe hemophilia, 11% had moderate, and 31% mild disease.
Two consecutive blood pressure measurements were conducted. Hypertension was defined as a systolic pressure (during heart contraction) above 140 mmHg, and/or a diastolic pressure (between heart beats) above 90 mmHg.
Overall, 239 patients had a known diagnosis of hypertension, 290 did not have high blood pressure, and values were missing for the remaining three people.
Among those with hypertension, a family history was reported for 117 participants, not reported in 75, and the remaining 50 had no data. Prophylactic (preventive) therapy was more common in those with (41%), than in patients without (25%), a family history of hypertension.
Hypertensive patients with a family history also had higher rate of macroscopic hematuria (67%) compared to other patients (51%).
In particular, researchers found that patients with macroscopic hematuria were almost twice as likely (1.84 times more likely) to develop hypertension if they had family history of high blood pressure. A subsequent analysis confirmed that macroscopic hematuria was associated with a greater risk of hypertension if linked with a family history.
The risk of hypertension linked with a family history was also higher as the number of hematuria episodes rose — a 1.98 times greater risk for less than three bleeding episodes, and a 3.14 times greater risk for more than 10 episodes.
With other studies, data here showed that diabetes and kidney diseases were significantly more prevalent in those with hypertension, with or without a family history, than they were in patients without elevated blood pressure.
Macroscopic hematuria also highly correlated with the severity of hemophilia, when controlling for body mass index and age.
These findings suggest a meaningful link between macroscopic hematuria and hypertension, challenging the general assumption that macroscopic hematuria is a harmless, “benign condition” in hemophilia patients.
“This paper demonstrated its association with hypertension FH+ [plus a family history],” the researches wrote. “This result is clinically important as hypertension in turn can lead to further renal damage, cardiac disease, peripheral vascular disease, and stroke.
“An increased attention given to macroscopic hematuria may restrict these adverse outcomes,” they added.
But they also acknowledged that their results “pertain to this study sample only,” and as such encouraged “more research to … ascertain whether the association between hypertension FH+ and hematuria holds more generally.”