Diagnosis and management of mineral metabolism in CKD

Chronic kidney disease (CKD) affects over 26 million Americans and is frequently complicated early in its course by disordered mineral metabolism and metabolic bone disease. Since CKD-related bone loss is often indistinguishable from osteoporosis by standard bone densitometry, many CKD patients may be inappropriately treated with bisphosphonates rather than CKD-specific therapies.

To determine the prevalence of appropriate evaluation, diagnosis and management of metabolic bone disease among individuals with pre-dialysis CKD.

Retrospective cohort study using electronic medical records of 69,215 ambulatory patients seen in the primary care clinics of an academic medical center.

Prevalence of CKD stages 3-4, frequency of diagnostic testing and treatment of metabolic bone disease.

Based on current diagnostic criteria and consistent with national data, CKD was present in 12% of the population. Bisphosphonates were used in 7.2% of patients, 20% of whom met criteria for CKD. Fewer than half of CKD patients underwent testing for parathyroid hormone (PTH) or 25-hydroxyvitamin D (25D) levels. Among those tested, vitamin D deficiency (25D <30 ng/ml) and secondary hyperparathyroidism (PTH >60 pg/ml) were present in 65% and 55%, respectively. Among patients with CKD, bisphosphonate use was nearly seven times as frequent as therapy with active vitamin D (12% vs. 1.7%, p < 0.0001), a primary treatment for CKD-associated metabolic bone disease.

Disordered mineral metabolism in CKD is common, under-diagnosed and under-treated. As a result, bisphosphonates may be prescribed inappropriately in patients with CKD.