Serum leptin levels do not correlate with disease activity in rheumatoid arthritis

Objectives: Leptin is a fat tissue hormone, which effects energy expenditure, food intake, hematopoiesis, osteogenesis, angiogenesis, reproductive and immune systems. We aimed to determine serum leptin levels and investigate the association between disease activity and other in parameters in rheumatoid arthritis (RA) patients. Methods: Patients with RA (n=106), as the study group, healthy controls (n=52) and osteoarthritis (OA) patients (n=37), as a control group, were enrolled to the study RA patients were categorized in four different groups according to DAS28 scores: remission, low (LDA), moderate (MDA) or high (HDA) disease activity. Results: No significant difference was present between the body mass indices of the three groups. Mean leptin levels in RA patients, OA group and healthy individuals were 25.60 +/- 13.41, 23.03 +/- 11.51 and 23.81 +/- 12.85 ng/ml, respectively and no significant difference was present between the groups. Nine of (8.5%) RA patients were in remission, 16 (15.1%) were in LDA, 40 (37.7%) in MDA and 41(38.7%) were in HDA. Leptin levels did not correlate with DAS28 scores of RA patients (r=-0.12, p=0.11). Mean leptin levels in RA patients in remission was 32.65 +/- 7.28; in LDA 23.94 +/- 10.94; in MDA 26.73 +/- 14.92 and in FDA 23.59 +/- 13.50 ng/ml (p=NS). No associations were observed between leptin levels and CRP, ESR, RF positivity and disease duration. Conclusions: Our study revealed no correlation of disease activity and serum leptin levels. Therefore leptin does not seem to be an appropriate biomarker to monitorize inflammation in RA.