Forearm osteoporosis is a well-known complication of primary hyperparathyroidism (PHPT). However, measuring forearm bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) at the distal radius is often neglected in clinical practice despite the fact that osteoporosis at any site is a criterion indicating surgery. We aimed to evaluate the importance and priority of forearm BMD and to determine its association with biochemical parameters.

Three hundred fourteen patients (272 females, 42 males) with PHPT who had BMD measurements at 3 sites were recruited for this retrospective study. The effect on surgical indications of osteoporosis only in the forearm was evaluated. Group 1 (n=151) with forearm osteoporosis and group 2 (n=163) without were compared in terms of biochemical and clinical parameters.

In the overall study population, 165 of the 314 patients had osteoporosis in at least 1 site. Twenty seven percent (n=86/314) had osteoporosis only in the forearm, while the other 2 sites (lumbar spine and femoral neck) were normal or osteopenic. Surgery was indicated based on osteoporosis only in the forearm in 10% of patients (n=30/314). Corrected calcium and parathyroid hormone levels were significantly higher in group 1 than group 2 (p=0.001 and p<0.001, respectively) and were also negatively correlated with distal radius BMD, T-score and Z-score in the whole study group.

Including the distal radius in BMD measurement increased the number of patients diagnosed with osteoporosis and for whom surgery was indicated. Calcium and PTH were also more frequently elevated in patients with forearm osteoporosis. These results show that distal radius BMD is relevant to the management of PHPT.