Role of serum adropin as a novel biomarker in primary knee osteoarthritis patients: Relation to the functional status, radiographic grading and ultrasonographic findings

Abstract

BackgroundKnee osteoarthritis (KOA) may lead to disabilities and affect work and daily activities. There is no specific blood test for its early diagnosis. Serum adropin is however a promising biomarker. Aim of the workTo determine the levels of serum adropin in primary KOA andassess its relation with the different radiographic grades of the disease. Patients and methodsA total of 40 primary KOA patients (64 affected knees) and 20 healthy control participated in this study. KOA grades was assessed using ultrasonography (US) and X-ray according to KL grading system. Serum adropin levels were measured. ResultsKOA was bilateral in 24 (60%) patients and knee effusion was present in 46 knees (71.9%). Serum adropin level in KOA patients (46.3 ± 27.9 pg/ml) was significantly lower than in controls (76.5 ± 27.2 pg/ml) (p < 0.00001). Serum adropin was lower in females than in males in patients (40.2 ± 17.7 pg/ml vs 75.2 ± 47.2 pg/ml; p = 0.0016). Serum adropin has significant negative correlation with the KL radiographic grading (r = -0.54, p = 0.0003).At cut off value of 54 and an AUC = 0.85, serum adropin could significantly distinguish between patients and controls (p < 0.05) at a sensitivity of 80%, specificity 90%. ConclusionsSerum adropin levels were significantly low in KOA patients with specificity of 90% and sensitivity of 80%, with a negative significant correlations with the degree of radiographic severity evaluated by KL grading scale and ultrasound. These findings suggest that low serum adropin levels could be a sensitive and specific test for the detection of KOA.