Effect of a single intravenous zoledronic acid administration on biomarkers of acute kidney injury (AKI) in patients with osteoporosis: a pilot study

The pilot study was designed to evaluate the early effect of intravenous (iv) zoledronic acid (ZA) on renal function. METHODS: Five mg iv ZA was administered to 23 patients with osteoporosis (17 women and 6 men, mean age 73±7 SD years). Urinary NGAL, KIM-1, and MCP-1, plasma (p) MCP-1 and serum (s) IL-18, serum calcium (sCa), Creatinine clearance (CrCl), parathyroid hormone (PTH), plasma C-terminal FGF23 (pFGF23), serum (s) Klotho, calcium excretion (CaEx) and renal threshold phosphate concentration/GFR (TmPO4/GFR) were assessed at baseline, 24 hours (h) and day (d) 30 after administration. RESULTS: There was a significant decrease in sCa and CaEx at 24 h (-4.1±2.8%, p<0.01 and -28±59%, p<0.05, respectively) and d 30 (-3.9±4%, p<0.001 and 26±43%, p<0.01) and a significant increase in PTH (79.8±95.8%) at d 30 (p<0.001) compared to baseline. TmPO4/GFR significantly decreased at 24 h and d 30 (-8.6±15.9%, p<0.05 and -11.3±13.5%, p<0.001) compared to baseline. We observed no difference in the concentration of pFGF23, sKlotho and urinary AKI biomarkers at any time occasions. Mean levels of sIL-18 and pMCP-1 significantly increased at 24 h (44±88%; p<0.01 and 198±237%; p<0.001) and returned to baseline at d 30. CONCLUSIONS: Our pilot study suggests that there is no direct acute effect of ZA on kidney function. The increase in plasma MCP-1 and serum IL-18 concentration could be associated with the stimulation of immunity mechanisms occurring soon after the administration of the drug. Secondary hyperparathyroidism develops shortly after the infusion of ZA and maintained even after one month.