Non-dialysis chronic kidney disease (CKD) patients receiving loop diuretics may have increased risks of developing secondary hyperparathyroidism (SHPT), according to a new study.
Researchers found that patients taking the loop diuretic furosemide had 3.9 times the risk of SHPT compared with those receiving the thiazide diuretic hydrochlorothiazide, even after adjustment for estimated glomerular filtration rate (eGFR).
“These observations, which are consistent with those obtained in the CRIC study, indicate that although LDs [loop diuretics] are often preferred over TTLDs [thiazides and thiazide-like diuretics] for the treatment of hypertension and edema in advanced CKD, they may aggravate bone metabolic disease in this setting,” Rosilene M. Elias, MD, PhD, of the University of Sao Paulo in Brazil, and colleagues wrote in the American Journal of Nephrology.
The investigators reviewed the charts of 275 outpatients from the university hospital with CKD stages 2 to 5, of whom 167 were prescribed furosemide and 108 hydrochlorothiazide. Hydrochlorothiazide users tended to be younger and female with higher eGFRs. SHPT was defined as serum parathyroid hormone levels exceeding 65 pg/mL.
Hypercalciuria has been suggested as a possible mechanism promoting SHPT. The researchers determined, however, that calcium excretion did not increase the risk for SHPT. Furosemide users had lower 24-hour urinary calcium excretion values (37 vs 47 mg/24 hours).
Prospective randomized trials are still needed to clarify whether hydrochlorothiazide confers protective effects or furosemide adverse effects, or some combination of both.