Effect of bisphosphonates on renal function in patients with osteoporosis

The aim of this study was to analyze renal function and its long-term evolution in patients treated with bisphosphonates (BP) for osteoporosis.MethodsOne hundred patients (89F/11 M) (mean age of 70 ± 9 years) treated with BP for osteoporosis during at least 1 year were consecutively included. Renal function (evaluated by serum creatinine and Cockroft-Gault for estimation of creatinine clearance [CrCl] before and after treatment), and clinical data (presence of hypertension, diabetes and anti-inflammatory treatment) were recorded in all patients. Renal insufficiency was considered as CrCl < 60 ml/min and impaired renal function as a decrease of ≥ 25% CrCl during treatment.ResultsThe mean treatment time with BP was 49 ± 31 months. Thirty-nine percent of patients had CrCl < 60 before starting BP and only three patients had creatinine ≥ 1.4 mg/dl. Patients with CrCl < 60 were older (78 ± 7 vs. 66 ± 7, P < 0.001) than patients with CrCl > 60. In the whole group, there were no significant changes in renal function during BP treatment (baseline creatinine 0.91 ± 0.2 vs. 0.89 ± 0.3 post-treatment; CrCl baseline 66 ± 20 vs. 66 ± 23 post-treatment, P = ns). However, 10% of patients had renal function impairment independently of the type of BP treatment and comorbidities. Age was correlated with serum creatinine values (r = 0.27, P = 0.007) and the changes of creatinine (r = 0.26, P = 0.009) and CrCl values (r = –0.25, P = 0.012). A CrCl < 45 ml/min was an independent predictor of renal function impairment.ConclusionsNearly 40% of patients treated for osteoporosis have renal insufficiency, a finding related to age. Although a significant decrease in CrCl was not observed in relation to BP treatment, 10% of patients showed impairment in renal function, suggesting the need to control CrCl in these patients.