Dose-specific effects of denosumab on serum calcium levels in patients with osteoporosis and various renal functions.

Abstract

Context: Patients with osteoporosis and advanced chronic kidney disease (CKD) are at increased risk for hypocalcemia when initiating denosumab. It remains unclear if subsequent doses of denosumab pose similar hypocalcemia risk as the initial dose does.

Objectives: To study dose-specific hypocalcemia risks of denosumab.

Design, setting, patients and exposure: An observational study of 10,398 consecutive patients with varying renal function who received denosumab within Mass General Brigham healthcare system between 1/1/2016 and 2/29/2024.

Main outcomes and measures: Dose-specific effects of denosumab on serum calcium levels and incidence of hypocalcemia (albumin-corrected serum calcium level < 8.5 mg/dl).

Results: In 159 patients with sufficient data for three consecutive doses of denosumab, the initial dose of denosumab reduced serum calcium levels by an average of 0.34, 0.52, and 1.12 mg/dl, in patients with GFR of ≥60 (n=89), 30-59 (n=46) and < 30 (n=24) ml/min/1.73m2, respectively (p<0.001). Among patients with GFR of < 30 ml/min/1.73m2, the initial, second, and third dose of denosumab reduced serum calcium levels by an average of 1.12, 0.72, and 0.60 mg/dl, respectively (p=0.014).In a cohort of 325 patients with sufficient data for two doses of denosumab, a Kaplan-Meier analysis revealed a trend of higher incidence of hypocalcemia following the initial dose compared to the second dose in patients with GFR of < 30 ml/min/1.73m2.

Conclusions: The magnitude of serum calcium decrease following subsequent dose(s) was smaller than that following the initial dose of denosumab among patients with osteoporosis and advanced CKD.