Obesity Linked to Worse Patient-Reported Outcomes in Rheumatoid Arthritis

Findings from a recent study are calling attention to the potential impact of obesity on patient-reported outcomes (PROs) in patients with rheumatoid arthritis (RA).¹

Patients with RA and obesity exhibited lower rates of patient-reported RA disease activity index (RADAI) and Boolean criteria remission compared to patients with normal weight. However, differences were primarily observed across subjective PROs as opposed to non-patient-reported elements indicative of objective disease activity.¹

“Obesity is a common comorbidity that is highly associated with poor social functioning and quality of life in patients with rheumatoid arthritis,” Mariana Drummond Martins Lima, a rheumatology resident at the Hospital das Clínicas of the Federal University of Minas Gerais, and colleagues wrote.¹ “It is directly linked to mental health issues and central sensitization to pain, potentially influencing patients’ subjective perception of disease activity.”

Although the exact causes of RA are unknown, obesity is widely recognized as a risk factor. Several key prevention strategies have been proposed to prevent RA and control disease progression, including lifestyle-related behaviors like not smoking, healthy nutrition, physical activity, and maintaining a normal body weight.² However, obesity’s impact on patients’ perception of their RA is not well explored.

To assess the relationship between obesity and PROs in long-standing RA, investigators examined data from the REAL study, a multicenter, observational cohort study of participants ≥ 18 years of age in Brazil who met the 2010 ACR/EULAR classification criteria for RA. Clinical-epidemiological and laboratory data were collected during the inclusion visit.¹

Investigators focused specifically on comparing data for patients with obesity, defined as body mass index (BMI) ≥ 30 kg/m2, and patients with normal weight, defined as BMI 18.5 - 24.9 kg/m2. Thus, patients classified as having overweight (BMI 25 - 29.9 kg/m2) were excluded from the present analysis.¹

Of the 1115 participants in the REAL study, 654 had BMI within the eligible ranges of interest in the present sub-study. In total, 299 (45.7%) participants were classified as having obesity and 355 (54.3%) were classified as having normal weight. The mean age was 57.1 (Standard deviation [SD], 11.8) years and most (89.4%) participants were female and had positive rheumatoid factor (RF) (77.2%).¹

Among the cohort, the mean disease duration was 14.5 (SD, 9.6) years and most patients were using corticosteroids (46%) or biological disease-modifying anti-rheumatic drugs (33.3%). The mean score for the simplified disease activity index (SDAI) was 14.7 (SD, 13.3), and for the patient-reported RADAI, it was 3.2 (SD, 2.2).¹

In multivariate analyses adjusting for sex, RF titers, corticosteroid use, bioDMARD use, and SDAI score, obesity remained an independent predictor for the following outcomes:

• Joint pain intensity (visual analog scale [VAS] 0-100 mm; β, 5.4; 95% CI, 1.3-9.5; P = .011)
• Fatigue (VAS 0-100 mm; β, 6.0; 95% CI, 1.0-11.0; P = .018);
• Patient global assessment (PGA) of disease activity (VAS 0-100 mm; β, 5.1; 95% CI, 1.2-9.0; P = .011)
• RADAI (β, 0.29; 95% CI, 0.04-0.55; P = .026)
• Boolean 1.0 remission (Odds ratio [OR], 0.35; 95% CI, 0.13-0.91; P = .032)
• Boolean 2.0 remission (OR, 0.40; 95% CI, 0.18-0.88; P = .022).

Investigators pointed out although patients with RA and obesity exhibited a reduced frequency of remission as assessed by RADAI and Boolean criteria, remission measured by SDAI did not differ significantly from patients classified as having normal weight. Additionally, further analysis of the components of the Boolean criteria revealed no significant differences across the groups in the non-patient-reported elements (C-reactive protein and physician-led counts of painful and swollen joints), accounting for the lower rate of Boolean remission in patients with obesity being primarily driven by patient global assessment. Likewise, investigators noted physician global assessment scores were not significantly different across groups, while other subjective outcomes such as fatigue and pain intensity were worse in participants with obesity.¹

“Overall, obesity was associated with worse scores on PROs, even when no clinical evidence for higher, objective, inflammatory activity was found. In spite of that, obese patients were more exposed to corticosteroids and bioDMARD, potentially indicating overtreatment, and ultimately implying higher management risks and costs in this group,” investigators concluded.¹

References

1. ^{Drummond Martins Lima M, Albuquerque C, Bagno de Almeida AL, et al. IMPACT OF OBESITY ON PATIENT-REPORTED OUTCOMES IN RHEUMATOID ARTHRITIS UNDER REAL-LIFE CONDITIONS: DATA FROM THE REAL STUDY. EULAR. doi:10.1136/annrheumdis-2024-eular.1105}
2. ^{World Health Organization. Rheumatoid Arthritis. Newsroom. June 28, 2023. Accessed June 28, 2024. https://www.who.int/news-room/fact-sheets/detail/rheumatoid-arthritis}