Obstacles in the Pursuit of Optimal Hyperkalemia Management
San Diego—Hyperkalemia is a condition in which potassium levels in the blood are elevated due to decreased kidney function. This condition is extremely common among Medicare-aged patients with chronic kidney disease (CKD) and heart failure (HF).
During a science and innovation theater at AMCP, Ross M. Miller, MD, MPH, FACPE, medical advisor, California Department of Health Care Services, reviewed the prevalence of hyperkalemia and limitations to managing the condition. The event was sponsored by Relypsa, Inc.
“The definition of hyperkalemia is variable,” said Dr. Miller. Hyperkalemia is most commonly defined as serum potassium levels in the blood ≥5 mEq/L. Clinical studies have documented serum potassium levels reaching as high as >6 mEq/L. “The higher the potassium level goes, the more consequences there may be clinically,” said Dr. Miller. “[When looking at potassium levels of] 5.5 mEq/L to 6 mEq/L, we are seeing increases in mortality that are fairly significant.”
In 2011, there were >60,000 occurrences in which hyperkalemia was the primary diagnosis for an emergency department visit. Of those >60,000 occurrences, almost 50,000 were identified as Medicare beneficiaries. In 2011, the total annual hospital charges for Medicare beneficiaries with a primary diagnosis of hyperkalemia were estimated at $697 million. The mean charge for each Medicare beneficiary stay was $24,085.
Hyperkalemia is common in patients with CKD. Renin-angiotensin-aldosterone system inhibitors (RAASi) drugs are often prescribed for preserving kidney function in CKD and reducing adverse cardiovascular events. However, RASSi drugs increase serum potassium levels, increasing the risk for hyperkalemia.
Dr. Miller discussed 4 studies that demonstrated the rates of hyperkalemia in patients with HF taking a min- eralocorticoid receptor antagonist (MRA). Two of the studies were clinical trials and the other 2 studies were real-world observations. In the 2 clinical trials, 2% and 2.5% of congestive HF patients developed hyperkalemia while on a MRA. The 2 observational studies showed 6% and 12% of CHF patients developed hyperkalemia while taking a MRA. “The incidence [of hyperkalemia] is even higher [in the observational studies] than in clinical trials of patients with HF who developed hyperkalemia when using a RAASi classified drug,” said Dr. Miller.
Dr. Miller referenced a study that assessed the abstention and discontinuation of RAASi therapy in 279 CKD patients. CKD patients who abstained from RAASi therapy due to a current hyperkalemia diagnosis or who were at risk for developing hyperkalemia was 13.8%. Discontinuation of RAASi therapy among CKD patients due to the development of hyperkalemia was 66.6%. “Hyperkalemia is a leading reason for either not starting RAASi drugs despite guideline recommendations or dis- continuing RAASi drugs once they are on them because of the development of hyperkalemia,” said Dr. Miller.
When hyperkalemia patients are in an emergency state, insulin or beta-adrenoceptor antagonists are recommended for treatment. If the hyperkalemia severity is considered intermediate, dialysis, loop diuretics, sodium bicarbonate, and calcium gluconate salt are common treatment options. Treatments recommended for maintaining hyperkalemia are sodium polystyrene sulfonate, titrating down RAASi treatment dosage, and implementing a low potassium diet.
There are multiple limitations to long-term treatment options of hyperkalemia. As previously mentioned, RAASi drugs increase the risk of hyperkalemia and titrating down the dose is not always sufficient. Sodium polystyrene sulfonate is linked to serious gastrointestinal adverse events that could cause a patient to discontinue the drug. Implementing a low potassium diet is difficult due to the large number of foods that contain the mineral. Patients cannot adhere to many diets due to their high potassium quantity including the DASH diet, which is recommended by the National Kidney Foundation and the American Heart Association.—Melissa D. Cooper
