PO:06:079 | Weighing the burden: how body mass index shapes clinical outcomes in rheumatoid arthritis. Insights from a large Italian cohort

Marco Capodiferro¹, Marco Fornaro¹, Gian Luca Erre², Matteo Piga³, Elena Bartoloni Bocci⁴, Andreina Manfredi⁵, Ennio Giulio Favalli⁶, Maria Sole Chimenti⁷, Serena Guiducci⁸, Eleonora Celletti⁹, Addolorata Corrado¹⁰, Alessandro Giollo¹¹, Simone Parisi¹², Ivan Giovannini¹³, Elisa Gremese¹⁴, Garifallia Sakellariou¹⁵, Ombretta Viapiana¹⁶, Fabiola Atzeni¹⁷, Francesca Romana Spinelli¹⁸, Fabio Cacciapaglia^1|19. | ¹Rheumatology Unit, Department of Precision and Regenerative Medicine and Ionian Area DiMePRe-J University of Bari, Bari, Italy; ²Dipartimento di Scienze Mediche, Chirurgiche e Sperimentali, Università degli Studi di Sassari, Sassari, Italy; ³Rheumatology Unit, AOU Cagliari, Department of Medical Sciences and Public Health, University of Cagliari, Cagliari, Italy; ⁴Rheumatology Unit, Department of Medicine and Surgery, University of Perugia, Perugia, Italy; ⁵Rheumatology Unit, Azienda Ospedaliera Universitaria Policlinico of Modena, Modena, Italy; ⁶Dpt of Rheumatology, G. Pini Institute, Milano, Italy; ⁷Rheumatology, Allergology and Clinical Immunology, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy; ⁸Department of Experimental and Clinical Medicine, Division of Rheumatology, University of Florence, Firenze, Italy; ⁹Rheumatology Unit, SS Annunziata Hospital, Chieti, Italy; ¹⁰Rheumatology Unit, Department of Medical and Surgical Sciences, University of Foggia, Foggia, Italy; ¹¹Rheumatology Unit, Department of Medicine, University of Padova Hospital Trust, Padova, Italy; ¹²Rheumatology Department, A.O.U. Città della Salute e della Scienza, Torino, Italy; ¹³Rheumatology Department, Santa Maria della Misericordia Hospital, Udine, Italy; ¹⁴Rheumatology and Clinical Immunology, IRCCS Humanitas Research Hospital, Rozzano (MI), Italy; ¹⁵Department of Internal Medicine and Therapeutics, University of Pavia, Istituti Clinici Scientifici Maugeri, Pavia, Italy; ¹⁶Rheumatology Unit, Department of Medicine, University and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy; ¹⁷Rheumatology Unit, Department of Experimental and Internal Medicine, University of Messina, Messina, Italy; ¹⁸Reumatology Unit, Department of Internal, Anesthesiological, and Cardiovascular Clinical Sciences, Sapienza University, Roma, Italy; ¹⁹Miulli General Hospital Acquaviva - Department of Medicine and Surgery, LUM F. De Gennaro University, Casamassima (BA), Acquaviva delle Fonti (BA), Italy.

Background. Body mass index (BMI) may influence the clinical presentation and progression of rheumatoid arthritis (RA). Understanding its impact is crucial to optimizing disease management and tailoring treatment strategies. This multicenter, cross-sectional study aimed to evaluate the impact of BMI on RA management in a real-world setting.

Methods. Patients diagnosed with RA based on the 2010 ACR/EULAR Classification Criteria were enrolled from 18 academic rheumatology centers. Clinical charts were reviewed to collect demographic data, treatment information, and disease activity measures. Data were analyzed using appropriate statistical methods with GraphPad Prism v9.

Results. A total of 1,432 RA patients were included (mean age 61±10 years; 81.4% female; median disease duration 120 months; 70% RF/ACPA positive). The median BMI was 25 (IQR 22.4–28.1), with males presenting significantly higher BMI values (p<0.001). Obesity (BMI >30 kg/m²) was observed in 14.7% of patients, with no significant sex difference. Overweight (BMI 25–30 kg/m²) was more common in males (1.5-fold, p<0.001), while underweight (BMI <20 kg/m²) was 10 times more prevalent in females (p<0.0001). BMI correlated positively with age, disease duration, blood pressure, triglycerides, CRP levels, and disability (assessed by HAQ-DI), but not with disease activity scores (DAS28-ESR or CDAI). A significant inverse correlation was observed with HDL cholesterol (r = -0.16, p < 0.0001). Smoking habits and diabetes prevalence (7.1%) were not significantly affected by BMI; notably, nearly half of diabetic patients were overweight or obese. The 10-year cardiovascular risk (SCORE-2) was similar between obese and non-obese RA patients. Regarding treatment, 43.5% of patients were on corticosteroids (mean prednisone-equivalent dose 4.9±3.4 mg/day), 68.7% on csDMARDs (80% on methotrexate), and 57.3% on b/tsDMARDs, with one-third receiving monotherapy. Obese patients were more likely to be treated with bDMARDs (64.3% vs. 56.1%, p=0.03; OR 1.41) and tsDMARDs (18.2% vs. 9.8%, p=0.007; OR 2.1), while no significant differences emerged for corticosteroid or csDMARD use.

Conclusion. This study highlights the influence of BMI on RA management in a large Italian real-life cohort. While BMI did not significantly affect disease activity, it was associated with increased disability and influenced therapeutic decisions, particularly the use of b/tsDMARDs. Gender differences were evident in BMI distribution, suggesting the need for personalized approaches in RA care based on body composition and sex-specific factors.