Renal safety of zoledronic acid infusion in osteoporosis patients: a retrospective analysis

Comert Kubra Yildiz; Kuru Elif Tuna; Adar Irmak; Atikcan Simsek Deniz Turkum; Ozcalik Merve Senay; Ozlem Iyidir

doi:10.1530/endoabs.110.P240

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Endocrine Abstracts (2025) 110 P240 | DOI: 10.1530/endoabs.110.P240

ECEESPE2025 Poster Presentations Bone and Mineral Metabolism (112 abstracts)

Renal safety of zoledronic acid infusion in osteoporosis patients: a retrospective analysis

Kubra Yildiz Comert ¹ , Elif Tuna Kuru ² , Adar Irmak ² , Deniz Turkum Atikcan Simsek ¹ , Merve Senay Ozcalik ¹ & Ozlem Iyidir ¹

Author affiliations

¹Baskent University, Internal Medicine, Ankara, Türkiye; ²Baskent University, Faculty of Medicine, Ankara, Türkiye

JOINT2379

Introduction: Zoledronic acid (ZA) is a bisphosphonate used for osteoporosis and malignancy-associated hypercalcemia. It is given intravenous infusion annually. While generally safe, isolated cases of acute kidney injury (AKI) have been reported, particularly in cancer patients receiving high cumulative doses, those with pre-existing renal insufficiency, and those with nephrotoxic therapy history. Kidney function monitoring, especially in older adults, is essential as AKI can also occur in low-risk patients. ZA is not recommended for patients with creatinine clearance below 35 mL/min. Osteoporosis guidelines suggest using the Cockcroft-Gault formula to estimate renal function before infusion, though many labs now report eGFR using the 2021 CKD-EPI formula. This study evaluates changes in serum creatinine (SCr), AKI incidence, and renal safety using eGFR (2021 CKD-EPI).

Methods: We retrospectively analyzed data from patients receiving at least two ZA infusions. Changes in SCr before and after infusion and AKI incidence within one year were recorded.

Results: A total of 452 infusions from 226 patients met the criteria. The mean age was 74. 2±9. 8 years, and 93. 4% were female. The baseline T-score was -2. 95±0. 86. 11. 5% had a baseline GFR <60 mL/min/1. 73 m² (stage 3 CKD). The mean baseline SCr was 0. 80±0. 18 mg/dL, with an average GFR of 78. 5±14. 8 mL/min/1. 73 m². The mean SCr increase was 0. 04 mg/dL (P < 0. 0001). Table 1 outlines renal outcomes. There was 5 (%2. 2) AKI, two of them progressed to chronic renal failure due to additional comorbidities. 124 of the patients were >75 years old. In older patients The average baseline SCr was 0. 83 (± 0. 19) mg/dl, corresponding to an average GFR of 71. 8 (± 13. 4) mL/min/1. 73 m2. The mean difference in SCr was 0. 06 (95% confidence interval, 0. 109–0. 02, P = 0. 002) lower in the after-period which was statistically significant.


	Preinfusion (n = 226)	Postinfusion (1. year) (n = 226)	p
Serum Creatinine (mg/dl)	0. 80 ±0. 18	0. 84±0. 24	<0. 001
GFR (mL/min/1. 73 m2)	78. 5±14. 8	74. 0±16. 8	<0. 001
Distribution (n, %)
≥60	197 (87. 2)	177(78. 3)
45-59	21 (9. 3)	34(15)
30-44	4 (2. 2)	12(5. 3)
<35	0 (0)	3(1. 3)

Discussion: Our study results show no clinically meaningful changes in serum creatinine (SCr) levels following zoledronic acid (ZA) infusions, and ZA-induced acute kidney injury (AKI) or renal failure was rare, occurring only in older patients receiving treatment for osteoporosis. While the 0. 04 mg/dL increase in SCr was statistically significant, we do not consider it clinically significant. Additionally, since the study had a maximum follow-up of one year, we cannot evaluate the long-term effects of treatment.