Impact of Obesity on Remission and Disease Activity in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis

ObjectiveTo summarize the relationship between obesity and remission in rheumatoid arthritis (RA); secondary objectives were to summarize other measures of treatment response and mortality in RA. MethodsMedline and Embase searches were performed in March 2016 using relevant MeSH and keyword terms for obesity and RA. Articles were selected if they reported estimates for achieving remission in obese subjects relative to other body mass index (BMI) categories, or changes in composite or individual disease activity measures or patient-reported outcomes during therapy, or mortality rates, in relation to BMI category or on a continuous scale. Remission outcomes were conducive to meta-analysis, and all other outcomes were summarized. ResultsA total of 3,368 records were screened; we included 8 reporting remission rates, 9 reporting disease activity measures or patient-reported outcomes, and 3 examining mortality by obesity status or BMI. Obese patients attain remission less frequently than nonobese and/or normal-weight patients. In adjusted models, obese patients demonstrated lower odds of achieving remission (pooled odds ratio [OR] 0.57 [95% confidence interval (95% CI) 0.45, 0.72]) and sustained remission (pooled OR 0.49 [95% CI 0.32, 0.74]) relative to nonobese subjects. Most studies found obese patients to have worse Disease Activity Scores or Disease Activity Scores in 28 joints, tender joint counts, inflammatory markers, patient global evaluation scores, pain scores, and physical function scores during followup, but not worse swollen joint counts. Obesity was not associated with increased mortality. ConclusionObesity decreases the odds of achieving remission in RA and negatively impacts disease activity and patient-reported outcomes during therapy. Interventions to reduce BMI should be investigated for their ability to improve disease outcomes.