High bisphosphonate treatment rates and the prevalence of atypical femoral fractures in patients with systematic lupus erythematosus: a single-center retrospective study performed in Japan.

Treatment of systemic lupus erythematosus (SLE) often continues with moderate-to-low doses of glucocorticoids for the long term. Bisphosphonates aid in the prevention and management of glucocorticoid-induced osteoporosis (GIOP). However, long-term use of bisphosphonates increases the relative risk of atypical femoral fracture (AFF) and the incidence is typically 16 or 113 per 100,000 person-years in patients treated with bisphosphonates for 5 or 10 years, respectively. Here, we explored bisphosphonate prescription rate and prevalence of AFF in patients with SLE. In total, 270 patients with SLE were enrolled. The Japanese Society for Bone and Mineral Research Guideline 2014 for GIOP management and treatment was used. We also explored AFF history through medical records. Most (n = 251) patients were recommended to treat by the GIOP guideline (scores ≥ 3); bisphosphonates, denosumab, teriparatide, or active vitamin D was prescribed for 85.7%. Bisphosphonates were currently used by 66.1% of the patients, and 65% had used them for ≥ 5 years. Of all patients, 76.7% had a history of bisphosphonate use, 5 of 270 (1.9%) had histories of AFF. Four of five patients with AFF had taken bisphosphonates for ≥ 3.5 years, in addition to moderate doses (≥ 10 mg/day) of glucocorticoids. For the SLE patients with a history of bisphosphonate use, the incidence of AFF was calculated to be 278 per 100,000 person-years. Our single-center study found that bisphosphonates were commonly used long term by Japanese patients with SLE. As AFF is not rare, AFF should be cared in patients with SLE.