Can the combination of calcium and parathormone levels above K/DOQI guidelines be used as a marker of adynamic bone disease in African Americans?

Background: Patients of African American descent are at risk for the development of adynamic bone disease at parathyroid hormone levels 50% above the K/DOQI guidelines. Since a low bone formation rate is associated with hypercalcemia, attempts to reach one K/DOQI guideline may result in serum calcium levels above another K/DOQI guideline. Calcium levels above K/DOQI guidelines therefore may signal a need to stop parathyroid suppression.

Setting And Participants: Bone biopsies were performed at the East Alabama Medical Center, in Opelika AL, USA on eight patients (four Caucasians, four African Americans) whose parathormone levels and serum calcium levels both exceeded K/DOQI guideline recommendations.

Results: All patients had mild to severe hyperparathyroid bone disease. No variable studied was predictive of the finding.

Limitations: Small sample size and the unavailability of the original Nichols Diagnostic Institute radioimmunoassay for parathormone.

Conclusion: We did not find hypercalcemia predictive of adynamic bone in patients of African American descent at levels of parathormone where low bone formation rates have been documented to occur. Since no parameter predicted bone histology, perhaps bone biopsies will be necessary to distinguish hyperparathyroidism from adynamic bone disease in African Americans with ESRD, hypercalcemia, and moderately elevated levels of PTH. Further studies are needed to determine appropriate therapy.