Obesity Is a Risk Factor for Remission Failure in Early RA

TOPLINE: 

Patients with obesity and early rheumatoid arthritis (RA) had an increased risk for remission failure after 6 months of starting methotrexate treatment, regardless of the presence of underlying comorbidities. 

METHODOLOGY:

• Researchers analysed data from a population-based case-control study linked to the Swedish Rheumatology Quality Register to investigate the association of obesity and/or overweight with the risk for remission failure in patients with early RA, accounting for comorbidities and lifestyle factors.
• They included 1285 adult patients newly diagnosed with RA (median age, 58 years; 70% women) who initiated methotrexate monotherapy between January 2006 and February 2018.
• Patients were categorised according to body mass index (BMI): Those with normal weight (BMI, 18.5-24.9; n = 598), those with overweight (BMI, 25-29.9; n = 453), and those with obesity (BMI ≥ 30; n = 217).
• Data on 31 different comorbidities, including cardiovascular, respiratory, and other conditions, were collected from the date of methotrexate initiation and for the 5 years preceding it.
• The primary outcome was 28-joint Disease Activity Score (DAS28) remission, defined as a score < 2.6 or DAS28–C-reactive protein < 2.4, at 3 and 6 months after methotrexate initiation. Secondary outcomes included Clinical Disease Activity Index remission, Simplified Disease Activity Index remission, Boolean remission, a good response, and no swollen joints.

TAKEAWAY:

• Six months after methotrexate initiation, 64% of patients with obesity, 52% of those with overweight, and 48% of those with normal weight did not achieve DAS28 remission.
• At 6 months, patients with obesity had a higher risk for remission failure than those with normal weight, after adjusting for comorbidities and other factors (adjusted relative risk [aRR], 1.27; 95% CI, 1.08-1.50), whereas no significant association was found in patients with overweight.
• Women with obesity were at a significantly increased risk for remission failure at both 3 months (aRR, 1.26; 95% CI, 1.08-1.49) and 6 months (aRR, 1.36; 95% CI, 1.13-1.62). Additionally, smoking was associated with a higher risk for remission failure at 6 months in both patients with obesity and those with overweight than in those with normal weight.
• The findings of an increased risk for remission failure were consistent across various secondary outcomes. Obesity was linked to an increased risk for inflammation among patients with overweight and obesity at 3 months.

IN PRACTICE:

“Our study confirms the previously described observation of an increased risk of remission failure among patients with obesity and early RA and extends this observation by demonstrating that this association could not be explained by the assessed comorbid conditions or lifestyle habits among patients with obesity,” the authors wrote.

SOURCE:

This study was led by Liselotte Tidblad, MD, Karolinska Institutet, Stockholm, Sweden. It was published online on April 15, 2025, in RMD Open.

LIMITATIONS: 

Data on height and weight were self-reported by patients. Data on comorbidities were primarily collected from specialised care, which may have excluded milder conditions managed in primary care. In subanalyses of comorbidity categories by BMI, some strata had very few observations, thereby limiting analysis.

DISCLOSURES:

This study was supported by Vinnova, Innovationsfonden, The Research Council of Norway, the Swedish Research Council, and other sources. Two authors reported receiving grants and having other financial ties with various pharmaceutical and healthcare companies. One author reported being a part-time employee of deCODE genetics, unrelated to this study.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.