833 patients, undergoing treatment with glucocorticoids for 12 months, were randomized to receive zoledronic acid or risedronate in this double blind, double dummy trial. This study assessed the non-inferiority of one injection of zoledronic acid for the prevention and treatment of glucocorticoid induced osteoporosis compared to the daily oral risedronate dosage. Following the one year treatment period, patients receiving treatment with zoledronic acid demonstrated a greater increase in bone mineral density. However, this treatment was associated with more adverse events.