Leptin is associated with disease activity but not with anthropometric indices in rheumatoid arthritis patients

Leptin is a cytokine-like hormone which has a complex role in inflammation. However, the importance of leptin in the pathogenesis of rheumatoid arthritis (RA) is far from being fully elucidated. The aim of the study was to determine serum leptin levels in RA patients and to evaluate whether there is an association between disease activity, anthropometric indices and leptin levels.

This hypothesis-generating study included 55 RA patients and 25 matched healthy subjects. The serum leptin concentration was determined by enzyme-linked immunosorbent assay (ELISA).

Median serum leptin level in RA patients of 27.4 ng/ml (14.5-54.9 ng/ml) was statistically significantly higher (p = 0.03) compared with the median leptin value of 16.3 ng/ml (9.6-38.8 ng/ml) determined in healthy controls. The serum leptin level in the high disease activity group was significantly higher (p < 0.0005) than that in the low disease activity group and in healthy controls. A significant difference (p = 0.001) in serum leptin level was also found when the high disease activity group was compared with the moderate disease activity group. In the RA group a statistically significant positive correlation (rho = 0.390; p = 0.003) was observed between serum leptin level and disease activity score (DAS28).

The present results show that serum leptin levels are increased and significantly associated with disease activity in patients with RA and may have a valuable role in the inflammatory reactions and pathogenesis of RA.