Severe obesity is a strong and independent predictor of progressive disability in patients with rheumatoid arthritis (RA), according to results published in Arthritis Care & Research.
The analysis included patients with RA from the National Data Bank of Rheumatic Diseases (NDB) (n=23,323; 58,425 person-years of follow-up) and the Veterans Affairs RA (VARA) registry study (n=1697; 4059 person-years of follow-up). Results from the Health Assessment Questionnaire (HAQ) or Multi-Dimensional (MD)-HAQ were recorded over follow-up. Significant worsening of RA was defined as an increase in HAQ or MD-HAQ of >0.2.
At study enrollment, disability scores were significantly higher in patients who were severely obese compared with patients who were overweight in both NDB (β: 0.17; 95% CI, 0.14-0.20; P <.001) and VARA (β: 0.17; 95% CI, 0.074-0.27; P =.001).
Based on multivariable models, patients who were severely obese at study enrollment had a significantly increased risk for progressive disability compared with overweight patients with RA, in both NDB (hazard ratio [HR], 1.25; 95% CI, 1.18-1.33; P <.001) and VARA (HR, 1.33; 95% CI, 1.07-1.66; P =.01).
Weight loss after study enrollment was also associated with a greater risk for disability in participants in both cohorts. These associations were independent of other clinical factors, including time-varying C-reactive protein and swollen joint count in the VARA registry. In participants from the NDB, a larger increase per year in HAQ was reported in participants with a history of weight loss of ≥5% since age 30 after adjusting for body mass index (BMI) at enrollment (β: 0.011; 95% CI, 0.005-0.017; P <.001). A loss of ≥5% in BMI since age 30 was also associated with a significantly greater risk for worsening disability independent of enrollment BMI (HR, 1.22; 95% CI, 1.18-1.26; P <.001).
The investigators concluded that severe obesity and weight loss are both associated with worse disability in patients with RA. The association between obesity and progressive disability in patients with RA does not appear to be attributable to differences in inflammatory disease burden and is similar to that expected in the general population. With respect to the link between weight loss and worsening disability, the investigators note that it is possible that patients with RA experience unintentional weight loss as a result of chronic illness or disease-related frailty.
Baker JF, England BR, Mikuls TR, et al. Obesity, weight loss, and progression of disability in rheumatoid arthritis [published online April 29, 2018]. Arthritis Care Res (Hoboken). doi:10.1002/acr.23579