Bone metabolic analysis in patients with primary hyperparathyroidism.

Surgical treatment for primary hyperparathyroidism (PHPT) improves not only the calcium and phosphate metabolism but also the bone metabolism. This study was conducted to analyze the bone metabolism after PHPT operations. Bone mineral density (BMD) was measured by dual-photon absorptiometry in 50 patients before and after operation. Osteocalcin (OC) and alkaline-phosphatase activity (Alp) in serum were measured before and after surgery as markers of bone formation, and urinary deoxypiridinorine (DPD) as an index of osteoclast activity. The 50 patients under study were 40 women (80%) and ten men (20%). Increases in BMD at the lumbar spine were remarkable at three months following operation. Slow but steady progress was made until six months, reaching a plateau thereafter. The increase in BMD of lumbar spine was approximately 10%. Urinary DPD was the most sensitive among the three bone metabolic markers. Although serum Alp and OC remained high after operation, urinary DPD was normalized earlier. The discrepancy of bone formation and resorption was shown after operation and this contributed to the increases in BMD in the first six months.