['The cause of rheumatoid arthritis (RA) flares is multifactorial and not well understood. No reports of fractures influencing disease activity in patients with RA have been published. The purpose of this study was to determine whether fractures influence disease activity in patients with RA.', 'Hospital records of 470 patients with RA between 2011 and 2014 were analyzed. We first examined the incidence of flare using multiple regression analysis. Secondly, we examined the incidence of flare using DAS28-ESR, DAS28-CRP, and drug changes before bone fracture until bone union in the fracture cases.', 'Multiple linear regression analysis showed that female sex (p\u2009<\u20090.001), bottom DAS28-ESR (p\u2009<\u20090.001), and fracture (p\u2009=\u20090.041) were independent factor for DAS28-ESR at the last observation period, and sex (p\u2009=\u20090.040), bottom DAS28-CRP (p\u2009<\u20090.001), and fracture (p\u2009=\u20090.019) were independent factor for DAS28-CRP at the last observation period. The average DAS28-ESR value was significantly increased from 3.19 (prefracture) to 3.58 (bone union). The average DAS28-CRP value was also significantly increased from 2.45 (prefracture) to 2.79 (bone union).'] Do fractures lead to worsening of disease activity in rheumatoid arthritis?