Low serum bicarbonate is independently associated with an increased risk of kidney disease progression in patients with chronic kidney disease (CKD), a study found.
The association is particularly strong in patients with preserved renal function, researchers reported online ahead of print in the American Journal of Kidney Diseases. Additionally, patients in the upper extreme of serum bicarbonate levels had an elevated risk of heart failure.
“In the context of the current literature, our study supports the concept of using serum bicarbonate level to identify patients with high risk of cardiovascular events and kidney disease progression,” the investigators wrote. “In addition, this epidemiologic association provides support to the notion that bicarbonate may be used as a therapeutic target to slow the decrease in kidney function.”
A team led by Mirela Dobre, MD, MPH, of the Division of Nephrology and Hypertension at University Hospitals Case Medical Center in Cleveland, studied 3,939 patients with CKD stages 2-4 who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study from June 2003 to December 2008. Study subjects had a mean estimated glomerular filtration rate (eGFR) of 44.8 mL/min/1.73 m2 and a median serum bicarbonate level of 24 mEq/L. During a median follow-up of 3.9 years, 374 subjects died, 767 had a renal outcome (end-stage renal disease [either initiation of dialysis or kidney transplantation] or a 50% reduction in eGFR), 332 had an atherosclerotic event (myocardial infarction, stroke, or peripheral arterial disease), and 391 had heart failure.
In adjusted analyses, each 1 mEq/L increment in serum bicarbonate level was associated with a significant 3% decreased risk of a renal outcome in the cohort overall and a significant 9% decreased risk among those with an eGFR above 45. Each 1 mEq/L increment in serum bicarbonate level above 24 mEq/L was associated with a significant 14% increased risk of heart failure. Serum bicarbonate level was not associated with atherosclerotic events and all-cause mortality.