Value of Serum Leptin in patients with Rheumatoid arthritis; Its Correlation With disease activity and Musculoskeletal Ultrasound findings

Aim of the work: Measurement of serum Leptin in rheumatoid arthritis patients (RA) and it's relation to clinical data, serological measures, disease activity, musculoskeletal US findings, and radiological joint damage score. Subjects and Methods: Our study included (40) patients with RA and (40) potentially healthy age and sex matched individuals as controls. Patients underwent full clinical assessment, assessment of disease activity by DAS28, measurement of serum leptin by ELISA. Plain x-ray hands and feet was done to all RA patients for evaluation of radiological joint damage using modified Larsen score which was done by an expert radiologist. Musculoskeletal ultrasound (MSUS) using the six joint power Doppler ultrasound (PDUS) scoring system for assessment RA joint findings. Results: There was no significant differences (p>0.05) between RA patients and controls as regards the mean level of serum Leptin with a mean of 22.60 ± 16.53 versus24.46 ± 17.06 respectively. There was no significant relation between mean serum leptin levels and the grades of disease activity of RA assessed by DAS28 (p>0.05). The mean serum leptin levels in RA patients showed no significant difference as regards the presence or absence of RF or the titer of anti CCP (p>0.05). The mean levels of serum cholesterol and LDL were higher in RA patients than the control with highly statistically significant difference (p<0.001). Also the mean levels of TG and HDL were higher in the patients than the controls with a statistically significant difference (p<0.05). There was a highly significant positive correlation between the mean serum leptin level and body mass index (r= 0.686, p <0.001), TG (r=0.80, p <0.001), cholesterol (r=0.76, p<0.001), and LDL (r=0,83, p<0.001) among our studied RA patients. There was no significant relation between radiological damage assessed by mean Larsen score and mean serum leptin level (p>0.05). Regarding the MSUS findings; tenosynovitis was found in 12 RA patients (30%), 36 patients (90%) had synovial hypertrophy, 18 RA patients (45% ) had synovial effusion. Positive power Doppler ultrasound signal (PDUS) was found in 23 RA patients (57.5%), showing grade 1 in 16 RA patients (40%), grade 2 in 7 RA patients (17.5%), PDUS score ranged from 0 to 10 with a mean of 3.08 ± 3.06. there was no significant relation or correlation as regard mean serum leptin level and the PDUS score (r=-0.008, p=0.095). Conclusion: Serum leptin levels have no significant correlation with RA clinical findings, disease activity score, serological data, musculoskeletal ultrasound findings and radiological joint damage in our RA patients. Factors as BMI, TG, cholesterol, and LDL influence serum leptin levels. So, according to our results, serum leptin doesn't seem to be a possible marker to monitor presence of inflammation or radiological joint damage in RA. [Sherin H Hamza and Takwa Badr Younes. Value of Serum Leptin in patients with Rheumatoid arthritis; Its Correlation With disease activity and Musculoskeletal Ultrasound findings. J Am Sci 2017;13(12):128-137]. ISSN 1545-1003 (print); ISSN 2375-7264 (online). http://www.jofamericanscience. org. 15. doi:10.7537/marsjas131217.15.