Treatment of osteoporosis in chronic kidney disease and end-stage renal disease.

As glomerular filtration rate (GFR) declines from age-related bone loss or disease that specifically induces a decline in GFR, there are a number of metabolic bone conditions that may accompany the decline in GFR. These metabolic bone conditions span a spectrum from mild-to-severe secondary hyperparathyroidism in early stages of chronic kidney disease (CKD) to the development of additional heterogeneous forms of bone diseases each with its distinctly quantitative bone histomorphometric characteristics. Osteoporosis can also develop in patients with CKD and ESRD for many reasons beyond age-related bone loss and postmenopausal bone loss. The diagnosis of osteoporosis in patients with severe CKD or end-stage renal disease (ESRD) is not as easy to do as it is in patients with postmenopausal osteoporosis (PMO)--neither fragility fractures nor The World Health Organization bone mineral density criteria can be used to diagnose osteoporosis in this population since all forms of renal bone disease may fracture or have low "T scores". The diagnosis of osteoporosis in patients with CKD/ESRD must be done by first the exclusion of the other forms of renal osteodystrophy, by biochemical profiling or by double tetracycline-labeled bone biopsy; and the finding of low trabecular bone volume. In such patients, preliminary data would suggest that oral bisphosphonates seem to be safe and effective down to GFR levels of 15 mL/min. In patients with stage 5 CKD who are fracturing because of osteoporosis or who are on chronic glucocorticoids, reducing the oral bisphosphonate dosage to half of its usual prescribed dosing for PMO seems reasonable from known bisphosphonate pharmacokinetics, though we do need better scientific data to fully understand bisphosphonate usage in this population.