Relationship of serum leptin hormone level and disease activity in rheumatoid arthritis patients

This study was set to investigate serum leptin levels in rheumatoid arthritis patients, and to find correlation of serum leptin levels in rheumatoid arthritis patients with disease activity. This study was conducted of thirty-five adult RA patients (30 females and 5 males) and 30 matching age persons were served as the control group. Assessment of disease activity was done using the DAS-28-ESR scoring system. Calculation of body mass index (BMI) was carried out for both RA patients and controls. Leptin ELISA Kit was used to measure serum leptin level in both RA patients and control groups. RA patients showed statistically significant higher mean of serum leptin level than control groups (26.65 ± 34.59 versus 13.57 ± 11.84 ng/dl respectively, P = 0.01). In addition, serum leptin level showed a statistically significant positive correlation with body mass index (P < 0.01). No significant correlation was found between serum leptin level and patients' age, disease duration and disease activity. Mean serum leptin level was 33.97 ± 38.73 ng/ml in seropositive patients and 8.36 ± 1.09 ng/ml in seronegative patients, a finding which proved to be statistically significant when comparing the two groups (P = 0.01). Even though serum leptin level was significantly higher in the RA patients than control groups, no correlation was found between leptin level and clinical and laboratory parameters of disease activity. However, the serum leptin level positively correlated with BMI in the RA patients. Keyword: Leptin, Rheumatoid arthritis, Inflammation, BMI