Changes in bone mass during low dose corticosteroid treatment in patients with polymyalgia rheumatica: a double blind, prospective comparison between prednisolone and deflazacort.

Abstract

To compare the long term effects of low dosage prednisolone or deflazacort treatments on bone mass in patients with polymyalgia rheumatica. Thirty patients with polymyalgia rheumatica were allocated on a random double blind basis to receive treatment with prednisolone or deflazacort. Bone mineral content (BMC) was measured in the lumbar spine and in the distal forearm before treatment and three, six, and 12 months after treatment. At three months the decrease in lumbar BMC and bone mineral density (BMD) was significantly greater in the deflazacort group than in the prednisolone group (p < 0.05), but at six and 12 months there was no difference between the two groups. In all patients after one year there was a significant loss of BMC: a 6.4% loss in lumbar BMC and a 1.8% loss in distal forearm BMC. Loss in lumbar BMC after six months was correlated to the cumulative dose of corticosteroid (r = 0.4; p < 0.05) and was significantly greater in the group of patients who had persisting symptoms of polymyalgia at six weeks, three months, or both, after treatment started (p = 0.05). This low dose study failed to reveal any calcium sparing properties of deflazacort compared with prednisolone. Possible explanations for this finding are discussed.