Early diagnosis and treatment of rheumatoid arthritis (RA) can minimize progressive joint damage and improve quality of life. But some RA patients still experience suboptimal outcomes, and a better understanding of modifiable factors, such as excess weight, may lead to improved outcomes. In RA patients, obesity has been associated with attenuated treatment response to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and other medications. Research has also associated obesity with disease activity measures and lower odds of achieving remission.
New research from Elizabeth Schulman, MD, and colleagues examined the independent effect of being overweight and obese on a patient’s ability to achieve sustained remission during the first three years after diagnosis. Researchers used data from patients enrolled between January 2007 and November 2014 in the Canadian Early Arthritis Cohort, a multicenter observational trial of early RA patients. During the study, 982 patients were categorized into three body mass index (BMI) groups: healthy BMI (n=315; 32%), overweight (n=343, 35%) and obese (n=324, 33%). Researchers defined sustained remission as a Disease Activity Score in 28 joints (DAS28) of less than 2.6 for two consecutive visits. The results were published in August 2018 Arthritis Care & Research.
The Results
“We found that [being] overweight and obesity significantly reduced the likelihood of achieving sustained remission,” write the authors. “Our findings suggest that a BMI [greater than] 25 is a negative prognostic factor associated with persistent disease activity.”
The study found no significant differences in the initial treatment strategies or frequency of methotrexate use across BMI groups. At baseline, 862 patients (88%) were treated with csDMARDs, 27 (3%) with biologics and 93 (9%) with steroids and/or NSAIDs. Treatment with methotrexate was common—739 patients (77%) had received it.
Within the three-year follow-up period, 355 patients (36%) achieved sustained remission. Overweight patients were 25% less likely to achieve sustained remission despite similar initial treatment, with worse outcomes seen in obese patients, of whom 47% failed to achieve sustained remission. In sensitivity analyses, researchers found that obesity was associated with reduced rates of improvement in all four individual component measures of the DAS28. An overweight BMI was primarily associated with reduced rates of improvement in tender joint counts.
Although the mechanisms linking persistent disease activity to excess weight are unclear, it’s also unclear if weight loss will lead to better outcomes.
With obesity rates on the rise, the authors note the importance of these findings for clinicians. They recommend clinicians identify patients at greater risk of persistent disease activity and discuss “data showing a negative impact of adiposity on early RA outcomes. For overweight and obese individuals, facilitating access to weight management programs and other community resources may be helpful for working toward achieving a healthier weight.”