Background Little is known about how lifestyle factors contribute to treatment response in early RA. We examined the relationship between body mass index (BMI) and smoking on the likelihood of achieving sustained remission in patients with early rheumatoid arthritis (ERA).
Methods ERA patients enrolled in the Canadian Early Arthritis Cohort (CATCH) with available BMI data were categorized using World Health Organization (WHO) weight categories: underweight (BMI<18.5), normal weight (BMI 18.5–24.9), overweight (BMI 25.0–29.9), obese I (BMI 30.0–34.9), II (BMI 35.0–39.9) and III (BMI>40 kg/m2). WHO-defined rates of obesity were compared to rates using RA sex-specific BMI thresholds1. Disease activity (DAS28), patient reported outcomes and medications were assessed at each visit. Multivariate regression using generalized estimating equations was used to assess the impact of BMI and smoking on achieving sustained remission (DAS28<2.6 at 2 consecutive visits).
Results BMI was available in 944 patients followed up to 3 years. Patients had a mean (SD) age of 52.75 (15.07), were mostly female (72%), Caucasian (79%), and had an average disease duration of 6.30 (3.56) months. 24% of patients were classified as obese and 28% overweight. When using recently proposed RA sex-specific BMI thresholds1, obesity rates increase in this cohort (53% of females, 80% of males). 17% reported currently smoking. After adjustment for sex, age, and race, baseline disability and pain, and early use of methotrexate (MTX), the odds of achieving sustained remission was significantly lower in patients who smoked and were underweight, overweight or obese (see table), although achieving LDAS by 6 months remains the strongest predictor of sustained remission.
Conclusions Overweight and obesity and smoking are common among early RA patients. Normal body weight and non-smoking status were independent predictors of achieving sustained remission after controlling for sociodemographic, disease and treatment characteristics. BMI and smoking should be considered amongst the modifiable lifestyle factors to improve likelihood of optimizing treatment and achieving sustained remission in early RA.
Katz, Patricia et al. “Gender Differences in Assessment of Obesity in Rheumatoid Arthritis.” Arthritis care & research 65.1 (2013): 62–70.
Disclosure of Interest S. Goodman: None declared, Y. Ma: None declared, W. Zhang: None declared, E. Schulman: None declared, S. Bartlett: None declared, K. Andersen: None declared, C. Hitchon: None declared, G. Boire: None declared, S. Jamal: None declared, J. C. Thorne: None declared, D. Tin: None declared, E. Keystone: None declared, B. Haraoui: None declared, J. Pope: None declared, V. Bykerk Grant/research support from: The CATCH study was designed and implemented by the investigators and financially supported initially by Amgen Canada Inc. and Pfizer Canada Inc. via an unrestricted research grant since the inception of CATCH. As of 2011, further support was provided by Hoffmann-LaRoche Ltd., UCB Canada Inc., Bristol-Myers Squibb Canada Co., AbbVie Corporation (formerly Abbott Laboratories Ltd.), and Janssen Biotech Inc. (a wholly owned subsidiary of Johnson & Johnson Inc.)