Predictive Value of Serum Leptin in Systemic Sclerosis: A Novel Analytic Cross Sectional Study

Background: Systemic sclerosis (SSc) is a chronic autoimmune and multi-systematic connective tissue disease. Leptin is a cytokine like and has role in regulating immune and inflammatory response.

Objectives: To assess predictive value of serum leptin in SSc patients.

Methods: Analytic cross sectional study was performed on 40 SSc patients diagnosed according to the 1980 criteria for classification of systemic sclerosis or 2013 American College of Rheumatology/ European League against Rheumatism for the classification of systemic sclerosis criteria and compared with 40 healthy controls matched in age, sex, and body mass index. Serum leptin levels were measured using Human Leptin ELISA kit with a sandwich format.

Results: Mean serum Leptin level was significantly higher in patients compared with controls ( Mean ± SEM was 10.89 ± 0.67 ng/ml Versus 6.92 ± 0.60 ng/ml, p<0.0001). Serum leptin was a valid and good test to differentiate SSc patients from healthy controls (AUC=0.80, P<0.0001). At optimum cutoff value >8.6 ng/ ml the test has highest accuracy of 80% with maximum sensitivity 82.5%, and specificity 77.5% and Mathew’s correlation coefficient (MCC) was 0.6. Also we can establish the diagnosis of SSc with 97.06 % confidence if the pretest probability of SSc was 90% and a negative result of the test can exclude the differential diagnosis of SSc with 97.6% confidence at 10% pretest probability.

Conclusion: Serum leptin was a valid good measure to differentiate patients with SSc from healthy controls with high accuracy, sensitivity and specificity and PPV and NPV and good MCC.