Urate-lowering Therapy Improves Kidney Function in CKD Patients, Study Shows

Urate-lowering Therapy Improves Kidney Function in CKD Patients, Study Shows

Patients with chronic kidney disease (CKD) who achieve ideal serum uric acid levels after being treated with a urate-lowering therapy show improvements in their kidney function, according to a study presented at the 2016 ACR/ARHP Annual Meeting Nov. 11-16 in Washington, D.C.

Chronic kidney disease (CKD) is a condition that causes a gradual loss of kidney function. The prevalence of the disease is increasing globally, with patients showing higher mortality rates and a reduced quality of life.

Gout is a painful disease that occurs when uric acid, a normal waste product, builds up in the blood and forms crystals in the joints or kidneys. Nearly 40 percent of patients with gout have CKD, and the incidence of gout increases as kidney function decreases.

In the new research, Gerald Levy, MD, MBA, a rheumatologist at Kaiser Permanente, and his colleagues investigated whether CKD patients could benefit from therapies that lower serum acid levels, commonly used to treat gout, until patients achieve an optimal American College of Rheumatology (ACR) level of less than 6 mg/dl associated with better kidney function.

The researchers also examined whether CKD stage at the start of the therapy would influence the benefits of a urate-lowering therapy (ULT).

The ACR Guidelines for Management of Gout recommend patient education on diet and lifestyle modifications along with initiating first-line urate-lowering therapies Uloric (febuxostat) or Zyloprim (allopurinol).

“Progressive kidney disease leading to dialysis impacts patients on a daily basis and represents a major cost to the healthcare system,” Levy, a lead author of the study, said in a news release. “Controlling diabetes and hypertension are the primary tools to prevent end-stage kidney disease. Normalizing serum uric acid level potentially is another tool to help prevent worsening kidney disease.”

The researchers identified 12,751 patients with serum urate levels higher than 7 mg/dl from 2008 to 2014. Patients’ index date was the first time they reached this mark. Glomerular filtration rate (eGFR), in the six months before the index date, was estimated for all patients. eGRF is the best test to measure the level of kidney function and determine the stage of kidney disease.

The study’s endpoint was either a 30 percent improvement or 30 percent decrease in eGFR results from baseline to study end.

During the study period, 2,690 patients were treated with a ULT and 10,061 patients were not. Overall, 42 percent of patients on a ULT achieved the serum urate level target. Of these patients, 17.1 percent also had a 30 percent improvement in their eGRF, compared to 10.4 percent of patients who did not achieve the target.

The researchers found that 7.1 percent of patients with Stage 2 CKD, 19.9 percent of patients with Stage 3 disease, and 30 percent of patients with Stage 4 CKD achieved a 30 percent improvement in eGRF. Patients with Stage 3 CKD showed the most clinical benefit from ULT in their kidney function.

“This study suggests that patients with CKD should be tested for uric acid independent of whether they have gout or not. In patients with significantly elevated serum uric acid and moderate kidney failure, the addition of urate lowering therapy may help stabilize or improve kidney function,” Levy said.

Daniela holds a PhD in Clinical Psychology from The University of Edinburgh, United Kingdom, a MSc in Health Psychology and a BSc in Clinical Psychology. Her work has been focused on vulnerability to psychopathology and early identification and intervention in psychosis.

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