Treatment of metabolic bone disease in patients with chronic renal disease: a perspective for rheumatologists.

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 distinctly quantitative bone histomorphometric characteristics. Osteoporosis can also develop in patients with CKD and end-stage renal disease (ESRD) for many reasons beyond age-related bone loss and postmenopausal (PMO) bone loss. Diagnosing osteoporosis in patients with severe CKD or ESRD is not as easy to do as it is in patients with PMO. The diagnosis of osteoporosis in patients with CKD/ESRD must be done by first excluding other forms of renal osteodystrophy, through biochemical profiling or by double tetracycline-labeled bone biopsy and the finding of low trabecular bone volume. In such patients 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. However, we need better scientific data to fully understand bisphosphonate usage in this population. This paper deals with the evidence available to understand management of patients with CKD and opinions on what might be a reasonable clinical approach where evidence is currently lacking.