New research demonstrated that obesity may be an independent risk factor for failure to achieve remission in patients with early rheumatoid arthritis, even after adjusting for comorbidities and lifestyle factors.
A Swedish team, led by Liselotte Tidblad, of the Karolinska Institutet, analyzed data from 1,285 patients with early rheumatoid arthritis (RA) who received methotrexate monotherapy between 2006 and 2018. The cohort, drawn from the Epidemiological Investigation of Rheumatoid Arthritis (EIRA) study, was stratified by body mass index (BMI): normal weight (18.5–24.9 kg/m²), overweight (25–29.9 kg/m²), and obesity (≥ 30 kg/m²).
The findings revealed a clear association between obesity and remission failure. After 6 months of treatment, 64% of the patients with obesity failed to achieve DAS28 remission compared with 52% of those with overweight and 48% of the patients with normal weight.
"Obesity is a risk factor for remission failure in early RA, independent of comorbid conditions," the study authors stated. The relative risk (RR) of remission failure in patients with obesity remained significantly elevated (RR = 1.27, 95% confidence interval [CI] = 1.08–1.50) even after comprehensive adjustment for age, sex, seropositivity, educational level, smoking, alcohol use, physical activity, calendar period, glucocorticoid treatment, and ten categories of comorbidities.
Notably, this effect was particularly pronounced in women and smokers, with women with obesity showing a 36% higher risk of remission failure at 6 months (RR = 1.36, 95% CI = 1.13–1.62) compared with women with normal weight. No statistically significant association was observed among the patients who were overweight.
The investigators also examined individual components of disease activity measures, finding that patients with obesity had increased markers of systemic inflammation (CRP and ESR) and higher patient-reported outcomes (pain and Patient Global Assessment) but showed no statistically significant difference in swollen or tender joint counts compared with patients with normal weight.
"The association could neither be explained by specific subjective (TJC, PGA, VAS pain) nor by objective (SJC, CRP, ESR) components of the remission metrics," the study authors wrote. "Whether the driving factor is an increased disease activity due to the RA disease itself, a worse perceived health and higher inflammation among patients with obesity, or both, remains to be determined," they concluded.
The new research could have implications for clinical practice, suggesting that rheumatologists should consider obesity as an independent risk factor when developing treatment strategies in patients with early RA.
Source: RMD Open