Bones and the Kidney

Management of osteoporosis in patients with chronic kidney disease (CKD) is often very challenging and it should consider the pathophysiology of both disorders. Patients with stage 4–5 CKD are especially at very high risk for fragility fractures and secondary increase in mortality. Discriminating between osteoporosis and CKD-MBD is best accomplished with quantitative bone histomorphometry but biochemical markers of bone turnover, especially intact parathyroid hormone (PTH) and bone-specific alkaline phosphatase, also may be helpful. The one renal bone disease where antiresorptive osteoporosis therapies would be potentially unsafe is idiopathic renal adynamic bone disease. The two renal bone diseases where an osteoporosis pharmacological agent would not be advised are osteomalacia and primary hyperparathyroid bone disease which can be excluded by defining the underlying cause of a high bone-specific alkaline phosphatase or defining the cause of a very high intact PTH. If a stage 4–5 CKD patient with fragility fractures is felt to have osteoporosis as the major underlying metabolic bone disease causing fractures, FDA approved pharmacological agents for the treatment of osteoporosis can be beneficial on or off label.