Background:Patients with rheumatoid arthritis (RA) and obesity have a lower risk of early death than patients with normal weight due to the so-called “obesity paradox”. Available publications discuss three phenotypes of obesity: classical obesity, metabolically healthy overweight/obesity, and latent obesity (normal weight associated with metabolic disorders, most importantly - with insulin resistance and adipocytokines imbalance).Objectives:To clarify the prevalence of obesity phenotypes and to identify factors predisposing to «latent obesity» in early RA without diabetes mellitus or hyperglycemia.Methods:The study included 35 pts (23 women, 12 men) with early RA (criteria ACR / EULAR, 2010), 56 [43,0; 60,0] years old, naïve to treatment with glucocorticoids and disease-modifying anti-rheumatics, without established diabetes mellitus. Pts were seropositive for IgM RF and anti-CCP, with highly active RA (DAS28 5,9 [5,2; 6,4]; SDAI 35,4 [27,0; 45,8], and CDAI 31,0 [26,0; 44,0]) scores, and median disease duration of 8.0 [6,0;15.0] months. Electrochemiluminescence assay Elecsys (Roche Diagnostics) was used to measure patients’ insulin levels, and ELISA (DBS – Diagnostics Biochem Canada Inc.) - for evaluation of serum leptin concentrations. Insulin resistance (IR) was defined as Homeostasis Model Assessment of Insulin Resistance index (HOMA-IR) ≥2,77. Leptin levels were considered elevated at values ≥11,1 ng/ml for women, ≥5,6 ng/ml for men. The overweight/obesity status was determined by World Health Organization criteria in pts with body mass index (BMI) ≥25kg/m2.Results:Overweight/obesity were documented in 19 (54, 3%) pts with early RA, 4/19 (21%) had high leptin levels and IR, 11/19 (58%) had isolated hyperleptinemia. Normal BMI was found in 16 (45,7%) pts with early RA, 2/16 (12,5%) had elevated leptin levels and IR, and 6/16 (37,5%) – only hyperleptinemia. Four (21%) out of 19 overweight and 8 (50%) out of 16 pts with normal BMI did not show any metabolic disorders (p=0,02). Сlassical obesity was found in 15 (43%), and latent obesity – in 8 (23%) pts with early RA. Leptin levels correlated with waist circumference (r=0,58, p=0,02), BMI (r=0,71, p=0,0006), ESR (r=0,5, p=0,02) in the overweight/obese pts, and with waist circumference (r=0,59, p=0,03), IgM RF (r=0,58, p=0,03), triglyceride levels (r=0,77, p=0,003), and atherogenic index (r=0,62, p=0,03) in pts with normal weight.Conclusion:The classical obesity phenotype associated with abdominal obesity and inflammation was the most common and prevailing over other phenotypes in early RA. Latent obesity was less common and was associated with an unfavorable lipid profile and accumulation of abdominal fat, therefore increasing the risk of cardiovascular diseases in RA. Metabolically healthy overweight/obesity in early RA was really a rare phenotype.Disclosure of Interests:None declared
Common genetic variation near MC4R is associated with waist circumference and insulin resistance
