Increased bone mineral density after parathyroidectomy in primary hyperparathyroidism.

Abstract

Skeletal involvement in primary hyperparathyroidism is characterized by preferential loss of cortical bone, whereas cancellous bone is relatively spared. Little data are available concerning changes in bone density, particularly at sites containing more cancellous bone, after successful parathyroidectomy. Most patients with primary hyperparathyroidism are asymptomatic, but approximately 50% meet one or more criteria for surgery. In a prospective study of 34 patients who met one or more such criteria, bone density rose at all skeletal sites (lumbar spine, femoral neck, and the radius) in the 4 yr after surgery. The lumbar spine, with most cancellous bone, showed a rapid (mean +/- SE, yr 1, 8.2 +/- 2.0%; P < 0.005) and sustained (yr 4, 12.8 +/- 2.8%; P < 0.001) rise. Post-menopausal patients were similar (by yr 4, 12.5 +/- 2.7%; P < 0.005). At the femoral neck, with intermediate cancellous and cortical composition, a similar increase was noted (12.7 +/- 3.8% by yr 4; P < 0.01). The distal radius, containing mostly cortical bone, rose modestly (4.0 +/- 1.5% by yr 3; P < 0.05), except in patients with lowest preoperative bone density, where the increase was marked (12.3 +/- 2.6% by yr 3; P < 0.05). In patients meeting surgical guidelines, parathyroidectomy is associated with improved bone mineral density.

Evaluation of Changes in Bone Density and Biochemical Parameters after Parathyroidectomy in Primary Hyperparathyroidism.

“…The present study on Japanese patients showed that annual increments in both the cortical and cancellous bone mass after PTX were larger than those in any other study previously documented in Caucasian populations, as judged by the percentage recovery of radial or lumbar BMD values (11.6% and 12.2%, respectively) ( Figure 1). Moreover, although two studies have reported that the percentage increase in lumbar BMD after PTX was greater than that in radial BMD in Caucasian populations [16,17], our study showed that the extent of BMD increases at the two sites were not significantly different. These discrepancies might arise from racial difference, or might be because our patients suffered from more severe reduction in radial bone mass than their Caucasian counterparts did, as judged by comparison of background BMD parameters documented in the previous studies.…”

“…These discrepancies might arise from racial difference, or might be because our patients suffered from more severe reduction in radial bone mass than their Caucasian counterparts did, as judged by comparison of background BMD parameters documented in the previous studies. The finding of a more pronounced increase in radial BMD values in a subset of patients with lower preoperative values at this site in several studies [14][15][16] would support the latter possibility. pHPT is a relatively common endocrine disease with few overt manifestations, presenting most often as asymptomatic hypercalcemia [1].…”

“…Several densitometric studies in Caucasian pHPT patients have indicated that the cortical as well as cancellous bone reductions are at least partially reversible after PTX with a range of annual increments of 4.0-9.9%, although they still remained lower than normal for several years after PTX [11- 16]. The present study on Japanese patients showed that annual increments in both the cortical and cancellous bone mass after PTX were larger than those in any other study previously documented in Caucasian populations, as judged by the percentage recovery of radial or lumbar BMD values (11.6% and 12.2%, respectively) ( Figure 1).…”

“…Taken together, this study shows that PTX causes dramatic improvements in both the cancellous and cortical bone mass in Japanese pHPT patients regardless of the severity of their osteopenia, and suggests that the cancellous and cortical bones react differently to a preoperative endogenous PTH excess and a high bone turnover rate as well as to the postoperative normalization of a bone turnover rate in the patients. The cortical and cancellous bones also seem to react differently to the normalization of a high circulating level of PTH and of a high bone turnover rate which occurred after parathyroidectomy (PTX) in pHPT patients.Bone mineral density (BMD) has been reported to increase after PTX in Caucasian pHPT patients [11][12][13][14][15][16], and two studies have shown that the percentage increase in BMD of the lumbar spine after PTX was greater than that in BMD of the radius [16,17] . However, such clinical studies have yet to be performed in Japanese pHPT patients, and thus it remains unclear whether or not PTX has a similar beneficial effect on bone mass, or whether or not the recovery of bone loss after PTX is different between the cortical and cancellous bones in Japanese patients.…”

“…Bone mineral density (BMD) has been reported to increase after PTX in Caucasian pHPT patients [11][12][13][14][15][16], and two studies have shown that the percentage increase in BMD of the lumbar spine after PTX was greater than that in BMD of the radius [16,17] . However, such clinical studies have yet to be performed in Japanese pHPT patients, and thus it remains unclear whether or not PTX has a similar beneficial effect on bone mass, or whether or not the recovery of bone loss after PTX is different between the cortical and cancellous bones in Japanese patients.…”