HF, hypertension difficult to manage in patients with CKD

BOSTON — Patients with chronic kidney disease are among the highest-risk population for HF, hypertension and all-cause death, but data show the use of renin-angiotensin-aldosterone inhibitors declines as the disease advances, according to a presenter at Cardiometabolic Health Congress.

Allan J. Collins, MD, FACP, director of the Chronic Disease Research Group and professor of medicine at the University of Minnesota, acknowledged that the use of ACE inhibitor and angiotensin receptor blocker therapy is particularly challenging in patients with advanced chronic kidney disease (CKD), in part because of the risk for hyperkalemia.

“I’m not here to tell you which therapies to use,” Collins said. “I’m here to tell you what the general doctors in this country use — or don’t use — as the CKD progresses. And it’s up to us to help guide them on what they could do.”

Collins cited a recent New England Journal of Medicine study outlining an increase in rates of hospitalization for HF and all-cause mortality as kidney function declines.

The death rate, Collins said, more than triples between CKD stage 3a to 3b, and then doubles again by stage 4, all while CV events rise, particularly in populations where the estimated glomerular filtration rate is less than 45.

“As these patients are progressing [with CKD], these events are accelerating,” Collins said. “They’re not just slowly going up, they’re exponentially going up.”

Citing Medicare data, Collins said 43% of CKD patients have a diagnosis code of HF; 27% have either had a stroke or transient ischemic attack and 15% have experienced acute MI.

“The CKD population is five to 20 times more likely to die than they are ever to get end-stage renal disease,” Collins said. “But, the patients are not afraid of death. I don’t know why they’re not afraid of death, but they’re afraid of dialysis.”

But Medicare data show that as CKD progresses, the use of ACE inhibitors and angiotensin receptor blockers declines, while the use of beta-blockers rises.

“In 2007, in the normal population, about half get an ACE [inhibitor] and angiotensin receptor blocker, but by the time they get to an advanced stage of CKD, only 42% of them are still getting an ACE [inhibitor] and angiotensin receptor blocker, while beta-blocker use has gone up,” Collins said.

Four years later, the numbers have not changed, Collins said, while beta-blocker use has climbed. By the time a patient has advanced to end-stage renal disease, only 35% are on ACE inhibitor or angiotensin receptor blocker therapy, he said. Calcium blocker channel use also rises, while few patients are prescribed potassium-sparing diuretics.

“It’s pretty clear that the therapies that are targeting HF are not being used during the time when the HF events are escalating,” Collins said. “These data suggest that providers are altering their therapies.”

Collins noted that RAAS inhibitor withdrawal in these patients may be used to lengthen the time to reach dialysis, but stressed that there are no randomized controlled trial data supporting this outcome.

“The exact time when RAAS inhibitor use is declining is when HF is rising,” Collins said. “This is why we have a therapeutic dilemma. RASS inhibitor [use] is discontinued frequently, yet the implications of this reduction and withdrawal need to be considered.”

Collins said clinicians should consider prescribing weaker diuretics along with RAAS inhibitors therapy to reduce the risk for hyperkalemia.

“You could use diuretic combinations to get it … you could use weak thiazide diuretics; you could use lower doses of loop diuretics,” Collins said. “What you’re after is presenting just enough sodium … to create the potassium exchange. You don’t have to hammer [patients] with the best combination [diuretic] to squeeze water out of a stone. You can use other ones, and there are plenty of them.” – by Regina Schaffer

Reference:

Collins AJ. Diabetes, kidney disease and hypertension. Presented at: Cardiometabolic Health Congress; Oct. 21-24, 2015; Boston.

Disclosure: Collins reports consultancy agreements or receiving research funding/honoraria from Amgen, Bayer, DaVita Clinical Research, Hospira, Keryx, NxStage Medical, Merck, Peer Kidney Care Initiative, Relypsa, and ZS Pharma.