Laxatives Lower Risk of Hyperkalemia in Advanced Chronic Kidney Disease
Constipation is one of the most common gastrointestinal disorders among patients with chronic kidney disease (CKD) partly because of their sedentary lifestyle, low fibre and fluid intake, concomitant medications (e.g., phosphate binders), and multiple comorbidities (e.g., diabetes). In a recent study, researchers have reported that laxatives significantly reduces the risk of hyperkalemia in advanced CKD. They also recommend administering laxatives with careful consideration for the risk-benefit profiles. The research has been published in the Journal of the American Society of Nephrology on March 31, 2021.
Intestinal potassium excretion is increased in patients with advanced CKD. They also often experience constipation partly due to a low-fibre diet to prevent hyperkalemia. It is possible that this compensatory mechanism is enhanced by laxative use, but little is known about the association of laxative use with the risk of dyskalemias in advanced CKD. Therefore, Dr Keiichi Sumida and his team conducted a study to examine the laxative use and risk of dyskalemia in patients with advanced CKD transitioning to dialysis.
The researchers included a total of 36,116 United States mostly male veterans with advanced CKD. Using generalized estimating equations with adjustment for potential confounders, they examined the association of time-varying laxative use with risk of dyskalemia (i.e., hypokalemia [potassium <3.5 mEq/L] or hyperkalemia [>5.5 mEq/L]) versus normokalemia (3.5–5.5 mEq/L) over the 1-year pre-ESKD period. Among 36,116 veterans, they noted 15,842 (5.0%) had hyperkalemia and 12,787 (4.0%) had hypokalemia in the year prior to end-stage kidney disease (ESKD).
Key findings of the study were:
- Over the last 1-year pre-ESKD period, the researchers identified 319,219 repeated potassium measurements in the cohort.
- Among 319,219 readings, they noted hypokalemia in 4.0% and hyperkalemia in 5.0% with the time-averaged potassium measurement of 4.5 mEq/L.
- Upon multivariable adjustment, they found that time-varying laxative use was significantly associated with 21% lower adjusted odds of hyperkalemia (serum potassium greater than 5.5 mEq/L) compared with nonuse.
- However, they found no relationship between laxative use and hypokalemia (serum potassium less than 3.5 mEq/L).
- They further noted that the results were consistent with several sensitivity analyses.
The authors concluded, " Laxative use was independently associated with lower risk of hyperkalemia during the last 1-year pre-ESKD period. Our findings support a putative role of constipation in potassium disarrays and also support (with a careful consideration for the risk-benefit profiles) the therapeutic potential of laxatives in hyperkalemia management in advanced CKD."
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