Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
TNF Inhibitors and the Risk of Fracture in Rheumatoid Arthritis.
Solomon3, Daniel Hal, Kim1, Seo Young, Liu2, Jun, Canning2, Claire, Schneeweiss2, Sebastian
Prior studies suggest an increased risk of fracture with RA. Potential causes include the underlying inflammation of RA as well as use of glucocorticoids. Several prior investigations demonstrate an improvement in bone mineral density associated with use of TNF inhibitors (TNFi). However, there are no studies comparing the risk of fracture related to different DMARDs in patients diagnosed with RA.
Our study cohort was drawn from two data sourcesa population-based cohort from a Canadian province and a large US commercial insurance plan. Patients with at least 2 diagnoses of RA were eligible for the study cohort at the time of a DMARD addition or switch. DMARD additions or switches were categorized into three mutually exclusive groups: 1) TNFi, with or without other DMARDs; 2) methotrexate (MTX), without a TNFi; or 3) other DMARDs, without a TNFi or MTX. Group 3 (other DMARD) was considered the reference group. Subjects were followed until they experienced a hip, humerus, wrist, or pelvis fracture based on diagnosis and procedure codes identified in the health care utilization data. The composite of any of these fracture types was considered the primary outcome. Incidence rates for fractures were compared across exposure groups. In addition, adjusted hazard ratios were calculated in Cox regression with covariates including age, gender, Charlson comorbidity index, prior fractures, oral glucocorticoids, other fracture risk factors, and health services utilization. Secondary analyses focused on groups with oral glucocorticoid use and prior fractures.
The study cohort consisted of 25,988 subjects with RA starting one of the three groups: 5,856 TNFi, 12,554 MTX, and 7,578 other DMARDs. Mean follow-up was 6 months. The three groups' characteristics were similar with respect to age, gender, and comorbidities, but differed with respect to oral glucocorticoid and opioid use, with higher rates for TNFi users. The incidence rates per 1,000 person-years for the composite fracture outcome were 5.11 (95% CI 3.507.45) for TNFi, 5.35 (95% CI 4.087.02) for MTX, and 6.38 (95% CI 3.7810.77) for other DMARDs. Adjusted hazard ratios for the primary outcome and secondary analyses are shown in the Table. The risk of fracture was similar across DMARD exposure groups.
Table. Adjusted hazard ratio (95% CI) for fracture among subjects with RA
|Main analysis (n = 25,988)||No recent steroid use (n = 18,157)||No prior fracture (n = 25,752)|
|MTX||1.18 (0.602.34)||1.20 (0.622.34)||1.17 (0.462.98)|
|TNFi||1.07 (0.571.98)||1.25 (0.602.61)||1.21 (0.542.71)|
Among subjects diagnosed with RA, the adjusted risk of fracture was similar across persons starting a TNFi, MTX, or other DMARDs. This result was robust across secondary analyses.
To cite this abstract, please use the following information:
Solomon, Daniel Hal, Kim, Seo Young, Liu, Jun, Canning, Claire, Schneeweiss, Sebastian; TNF Inhibitors and the Risk of Fracture in Rheumatoid Arthritis. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1066