Effect of Chronic Corticosteroid Administration on Diaphyseal and Metaphyseal Bone Mass

Abstract

Bone mass was measured by the photon absorption technique in the forearm of 490 normals, 36 patients with idiopathic osteoporosis, 21 patients with rheumatoid arthritis who had not received corticosteroid therapy, 48 patients who had been maintained on corticosteroid therapy for one or more years, 2 patients with Cushing's disease and 25 patients with primary hyperparathyroidism. Measurements were made at two points along the radius, a proximal diaphyseal site which is comprised primarily of cortical bone (DM) and a distal metaphyseal site reflecting a greater proportion of trabecular bone (MM). Patients with idiopathic osteoporosis and rheumatoid arthritis not treated with steroids both showed a parallel percentage loss of bone mass at the DM and MM sites, a pattern similar to the pattern of bone loss seen in normal subjects with aging. In contrast, patients with primary hyperparathyroidism and corticosteroid-induced osteopenia both showed a significantly greater degree of loss at the MM site. The amount of DM and MM loss, and the degree of disproportionate MM loss, in corticosteroid-treated patients correlated positively with duration of therapy. The similar pattern of bone loss in primary hyperparathyroidism and corticosteroid-induced osteopenia suggests that increased parathyroid activity may play a significant role in the bone loss associated with chronic corticosteroid therapy.