Efficacy of discontinuing risedronate for patients with systemic lupus erythematosus: a prospective study

Objective The objective of this study is to investigate the effectiveness of discontinuation of risedronate for patients with systemic lupus erythematosus (SLE) treated with glucocorticoid (GC). Methods The participants were patients with SLE treated with prednisolone (PSL)2mg/day and risedronate for at least three years. Lumbar spine and total hip bone mineral density (BMD) measurements were taken at baseline and 24 and 48 weeks after discontinuation of risedronate, and bone turnover markers were evaluated at baseline, 12, 24, 36, and 48 weeks. Results A total of 36 patients were enrolled, 25 of whom discontinued risedronate. The mean age was 46.811.2 years, and 23 were female. The mean duration of GC treatment was 14.8 +/- 11.4 years, the mean dose of PSL was 7.8 +/- 3.9mg/day, and the mean duration of risedronate was 5.8 +/- 2.4 years. Seventeen patients showed decreased lumbar spine BMD at 48 weeks after discontinuation of risedronate, with a mean lumbar spine lumbar decrease of 1.42%+/- 3.20% (p=0.034); 17 patients (71%) showed a decreased total hip BMD at 48 weeks after discontinuation of risedronate, with a mean total hip BMD decrease of 0.99%+/- 2.10% (p=0.021). Serum tartrate-resistant acid phosphatase 5b (TRACP-5b)309mU/dl at baseline was a risk factor for decreased total hip BMD at 48 weeks compared with serum TRACP-5b<309mU/dl (56% vs 0%, p=0.0098). One patient developed a clinical fracture of the lumbar spine at 20 weeks. Conclusions Discontinuation of risedronate treatment in patients with SLE who had received GC therapy led to decreases in lumbar spine and total hip BMD, particularly in patients with high baseline serum TRACP-5b levels.