Assessment of oral bisphosphonate use in elderly patients with varying degrees of kidney function

Oral bisphosphonates are prescribed for millions of men and women in the United States who have osteopenia or osteoporosis. However, there are limited data on the use of oral bisphosphonates in patients with kidney impairment.

The purpose of this study was to evaluate changes in calculated creatinine clearance (CrCl) and reported adverse events in elderly patients with varying degrees of kidney function who were taking oral bisphosphonate therapy.

The present study was a retrospective review of the medical records of elderly patients (age range, 65-89 years) who were prescribed oral bisphosphonates for a diagnosis of osteoporosis or osteopenia at the University of Colorado Hospital Seniors Clinic during the period January 1999 through March 2003. Data on age, sex, body weight, height, blood urea nitrogen and serum creatinine concentrations, and adverse-reaction history were collected. Clinic notes were reviewed to determine whether patients had taken an oral bisphosphonate previously or whether bisphosphonate therapy was initiated during the study period. The Cockcroft-Gault equation was used to calculate CrCl. Rates of drug-related adverse events were compared in patients with and without severe kidney impairment. For the purposes of this study, severe kidney impairment was defined as a CrCl <35 mL/min.

Data from 181 patients (88.4% female, 11.6% male; mean age, 79.2 years) who received oral bisphosphonates were included in the analysis. One hundred fourteen (63.0%) patients began bisphosphonate therapy during the study period. The mean duration of bisphosphonate therapy was 22.3 months. Thirty-one (17.1%) patients taking bisphosphonates had severe kidney impairment. There was no change in calculated CrCl after the initiation of oral bisphosphonate therapy in patients who started therapy during the study period. Adverse drug events, 19 of them related to the gastrointestinal system, occurred in 24 (13.3%) patients. Overall, 19.4% (6/31) of patients with severe kidney impairment and 12.0% (18/150) of those without severe kidney impairment experienced adverse events; the difference between groups was not statistically significant. No reported adverse drug event required hospitalization or emergency treatment.

When prescribed for elderly patients with varying degrees of kidney function, oral bisphosphonate therapy was well tolerated and was not associated with a decline in calculated CrCl.