Primary hyperparathyroidism: Effect of parathyroidectomy on regional bone mineral density in Danish patients: A three-year follow-up study

Changes in skeletal remodeling (biochemical bone markers) and regional bone mineral density (spine, hip, and forearm bone mineral density [BMD]) were observed for 3 years in 20 patients (15 women and 5 men; age 54 +/- 11 year s, range 29-69 years) after successful surgery for primary hyperparathyroid ism (PHPT). Fifteen PHPT patients were compared with 15 normal controls who were exactly matched with respect to age, gender, and menopausal status (1 0 women and 5 men; age 53 +/- 12 years, range 29-65 years [PHPT] and 29-66 years [controls]). All bone markers (serum osteocalcin, bone alkaline phosp hatase, and type I collagen telopeptide [ICTP], and urinary hydroxyproline and NTx/creatinine ratio) declined significantly and reached normal levels within 6 months. No major changes took place during the remaining 2.5 years , apart from urine hydroxyproline, which disclosed a small peak around 12 m onths with a further decline towards study end (p < 0.05). Bone mineral den sity increased significantly in all regions (p < 0.001). At all locations, except the intertrochanteric region of the hip, the increase continued from 6 months until study end (p < 0.05). The increase in BMD was unequally dis tributed among regions (p < 0.001). The increase at the proximal forearm wa s less than in the spine (p < 0.05), the trochanteric region of the hip (p < 0.05), and the distal forearm (p < 0.05). No difference in BMD increase w as observed between men, and pre- and postmenopausal women. Compared with t he matched control group, PHPT patients had significantly lower BMD at base line in the proximal (p < 0.02) and distal (p < 0.05) forearm. Furthermore, during the 3-year follow-up period, the PHPT patients showed a significant increase in BMD compared with controls in the spine (p < 0.005), the troch anteric and intertrochanteric regions of the hip (p < 0.005 and p < 0.05, r espectively), and the distal forearm (p < 0.005). In conclusion, bone remod eling is normalized within the first 6 months after successful parathyroid surgery, with no major changes during the following 2.5 years. Bone mineral density increases at both cancellous and cortical sites, but in predominan tly cortical bone, the recovery in BMD is less than in cancellous bone-rich areas. (C) 1999 by Elsevier Science Inc. All rights reserved.