Chicago, IL - A new survey has found that although chronic kidney disease (CKD) patients have a high awareness of hypertension, just 13% of them had their blood pressure under control [1]. Dr Pantelis A Sarafidis (University of Chicago Pritzker School of Medicine, IL) and colleagues report their results in the April 2008 issue of the American Journal of Medicine.

"One of the most important findings of our study was that the people at the highest risk for progressing to end-stage renal disease—men, non-Hispanic blacks, and the obese—were the ones least likely to have their blood pressure at goal or controlled, even though they were generally seeing a physician and being treated. This indicates that we need to be much more aggressive with educational endeavors in these patients to ensure that they actively achieve their BP goals," senior author Dr George Bakris (University of Chicago Pritzker School of Medicine) told heartwire.

High blood pressure is a leading cause of kidney disease and hastens its progression to renal failure, Bakris explained. "It's unacceptable that barely 10% of people most at risk of kidney and cardiovascular problems have gotten their blood pressure under control."

The researchers surveyed 10 813 people in the US National Kidney Foundation's (NKF) Kidney Early Evaluation Program (KEEP), a health-screening program for individuals at high risk for kidney disease.

The study is the first to provide data on the prevalence, awareness, and treatment of hypertension in a CKD cohort, Sarafidis et al note. They found that 86.2% of participants had hypertension, 80.2% were aware that they had hypertension, and 70% were being treated for hypertension. But blood-pressure control rates were low—at just 13.2% when the BP goal was <130/80 mm Hg.

Comparing these figures with a previous nationwide survey (the National Health and Nutrition Examination Survey), the prevalence, awareness, and treatment of hypertension in this cohort was comparable, but the blood-pressure control "was far worse," say Sarafidis et al.

One surprising finding, said Bakris, was the fact that "the more advanced the stage of kidney disease, the greater likelihood there was that people achieved BP control than those at earlier stages of renal disease." Patients with stage 4 to 5 kidney disease had a threefold higher blood-pressure control rate than those with stage 1.

"This is interesting," he says, "because you wouldn't predict that, as it's much easier to control blood pressure at earlier stages of kidney disease."

Smokers also had a higher likelihood of having blood pressure controlled, a finding that the researchers say is "unusual" but may be explained by the fact that this group had much lower rates of obesity.

The other important finding relates to the subgroups of males, blacks, and the obese, Bakris says. Male gender was inversely associated with blood-pressure control (odds ratio 0.86), as was non-Hispanic black race (OR 0.76) and body-mass index of 30 kg/m² or greater (OR 0.83).

We need to focus more on blacks, males, and obese patients because they are at higher risk of progression in the first place.

"Yet black males account for a very large percentage of people going on to end-stage kidney disease," he stresses, "so this is an observation that suggests we need to focus more on blacks, males, and obese patients, because they are at higher risk of progression in the first place. There is something missing in these subgroups that needs attention."

And although it is encouraging that a physician had diagnosed 80% of people surveyed with hypertension, Bakris said, it is not possible, from these data, to explain why blood pressure is not being adequately controlled.

"Cardiologists and other specialists, as well as primary-care physicians, need to be much more attentive to the level of kidney function," he adds, "and much more aggressive about trying to achieve BP goals and educating patients so that they understand why they have to take their medicine."

The NKF will offer free kidney screenings through KEEP in 40 cities across the US on World Kidney Day, on March 13, and throughout March, says Bakris, who is on the KEEP steering committee and is also a member of the NKF scientific advisory board.