CONCISE REPORT Stress fractures in rheumatoid arthritis: a case series and case-control study

Objective : To review cases of stress fracture in patients with rheumatoid arthritis (RA) presenting to our service over a 10 year period; to identify possible risk factors and test these in a case-control study. Methods: A retrospective case note review of all patients with a final diagnosis of stress fracture, presenting between 1990 and 1999 was performed. A case-control study of consecutive patients with RA, matched for age, sex and duration of disease, attending the same clinics. Results: Case series: 24 stress fractures were identified in 18 patients, representing 0.8% of the RA clinic population; all were women, median age 69.5 years (range 47–79). Bone mineral densitometry showed median T scores of 23.06 and 22.27 SD at the hip and lumbar spine, respectively. Casecontrol study: In the stress fractures group, past steroid doses were higher (p = 0.003). No significant differences in the bone mineral density (BMD) T score at the hip or lumbar spine were found (p = 0.59, p = 0.77). Conclusions: Stress fractures are a significant cause of morbidity in RA. Diagnosis is often delayed and presentation can be misleading. Past steroid use, particularly at higher doses, confers an increased risk of stress fracture, but the increased risk is not attributable to osteoporosis as assessed by BMD.