SAN FRANCISCO – Nocturia is a sign of uncontrolled hypertension and also is associated with diuretic use in middle-aged black men, according to a study conducted at 53 barbershops in and around Los Angeles.
In the study, investigators averaged the last three of five automated blood pressure readings in 1,748 black men aged 35-49 years old and asked them about symptoms of nocturia – defined in the study as getting up two or more times per night to urinate – and about what blood pressure medications they were taking, if any.
Men with untreated hypertension – defined as at or above 135/85 mm Hg – were 34% more likely to report nocturia than were men who were normotensive.
However, “what really grabbed our attention was the treated group,” lead investigator Ronald Victor, MD said at the joint scientific sessions of the AHA Council on Hypertension, AHA Council on Kidney in Cardiovascular Disease, and American Society of Hypertension.
The highest risk of nocturia, more than three times the risk of normotensive men, was among men treated with a diuretic who still had elevated blood pressure readings in the barbershop. Their risk was about 2.5 times greater in men who were treated but uncontrolled and were not on a diuretic, said Dr. Victor, director of the hypertension center at Cedars-Sinai Medical Center, Los Angeles.
Among men treated and controlled down to a systolic blood pressure of almost 120 mm Hg, those with a diuretic included in their regimen had about twice the risk of nocturia as did normotensive men; those controlled without a diuretic had no elevated risk of nocturia. The results were statistically significant and were adjusted for nocturia confounders, including diabetes, body mass index, sleep apnea, and an enlarged prostate.
“Nocturia is far more likely when hypertension is inadequately treated,” especially with a diuretic, than when untreated, Dr. Victor said. “The data suggest that nocturia may be a side effect of blood pressure drugs unless strict blood pressure control is achieved. Appropriate treatment of blood pressure without a diuretic may be really beneficial in terms of reducing nocturia.”
Not all the data on the specific medications the men in the study were taking were available, but the most common antihypertensive prescribed for them was short-acting, low-dose hydrochlorothiazide, he noted.
It has been shown that hydrochlorothiazide wears off in the evening when dosed in the morning, so blood pressure might appear to be well-controlled in the daytime, but patients become hypertensive at night, leading to pressure natriuresis and nocturia. “This might [help] explain our data,” Dr. Victor said, noting that longer-acting, more potent diuretics, such as chlorthalidone, might reduce the risk.
The team plans further work to see if tighter nighttime blood pressure control reduces nocturia and improves sleep. Maybe, he noted, “if you take your blood pressure meds correctly, you sleep better. That would be a fantastic public health message; we’ll see.”
Middle-aged black men are underrepresented in hypertension research, in part because of a mistrust of doctors and medical institutions. Enrolling black men in barbershops seemed a good way to address the problem; barbers are trusted and respected members of the community, and the shops themselves are warm and relaxed, which is why hypertension was defined in the study a bit lower than the usual 140/90 mm Hg, Dr. Victor commented.
A total of 45% of the men were hypertensive; only 16% were controlled on medication. Nocturia prevalence was higher than expected in the general population, at about 29% overall, and ranged from 24% in normotensive men to 50% in men whose hypertension was treated but uncontrolled.
Average blood pressures were 120/71 mm Hg in the normotensive men; 143/87 mm Hg in untreated hypertensive men; and 148/91 mm Hg in treated but uncontrolled men. The mean age in the study was 43 years. “We capped it at 49 because after that, nocturia is so prevalent, and dominated by prostate disease,” Dr. Victor said.
The investigators had no disclosures. The National Institutes of Health funded the work.