Risks of femoral localized periosteal thickening in patients with autoimmune inflammatory rheumatic diseases

Objectives The incidence of femoral localized periosteal thickening (LPT), which can precede atypical femoral fracture (AFF), is not low (1-10%) in Japanese patients with autoimmune inflammatory rheumatic diseases (AIRDs). We explored the associations between underlying AIRDs and the prevalence of LPT. Methods We conducted post hoc analyses of two cohorts that included a total of 280 Japanese women, 105 of whom had AIRDs and had been taking bisphosphonate (BP) and prednisolone (PSL) and 175 of whom had rheumatoid arthritis (RA). Results LPT was detected in a total of 18 patients (6.4%) and 3 (1.1%) developed AFFs. RA was negatively correlated with LPT. A disease other than RA requiring glucocorticoid treatment, BP use >= 5 years, PSL use >= 7 years, and a PSL dose >= 5.5 mg/day were positively correlated with LPT. After adjusting for age, diabetes mellitus, and BP duration or daily PSL dose, RA was no longer associated with LPT. Conclusions LPT in Japanese patients with AIRDs was associated with BP and glucocorticoid treatment rather than underlying AIRDs. When PSL dose >= 5.5 mg/day is required long-term [typically combined with long-term BP treatment (>= 5 years)], clinicians need to pay particular attention in cases LPT and AFF as well as glucocorticoid-induced osteoporosis.