201 patients with a rheumatic disease who were starting daily doses of glucocorticoids were randomized to receive 10 mg of alendronate and a placebo capsule of alfacalcidol daily or 1 ug of alfacalcidol and a placebo tablet of alendronate daily. At 18 months, the lumbar spine bone mineral density of patients who received alendronate had increased significantly more than that of the patients who received alfacalcidol. In addition, there were significantly fewer patients in the alendronate group who had a new morphometric vertebral deformity compared to the alfacalcidol group after 18 months. Alendronate is therefore more effective than alfacalcidol in reducing the bone loss caused by glucocorticoids.