The Role of Neutrophil to Lymphocyte Ratio and Platelet to Lymphocyte Ration in Diagnosis of Subacute Thyroiditis

Abstract

Purpose: Patients with subacute thyroiditis (SAT) usually apply to clinics with thyrotoxicosis and neck pain. Hemogram is frequently applied tests in primary health care services, and it can warn physicians for SAT in a thyrotoxic patient. In our study, the role and usability of neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) in the diagnosis of SAT were evaluated. Material and Methods: Between January 2015 and January 2020, 192 SAT patients who applied to endocrinology clinics and 85 healthy control were included in the study. Neutrophil (Neu), lymphocyte (Lym), platelet (PLT) leves were recorded. Results: The median NLR and PLR values of SAT patients before treatment were 2.78 (0.91-11.33) and 168.3 (25.7-818.3), respectively, and were significantly higher than the control group (p<0.001). The optimum cut-off values for NLR and PLR for SAT were 1.84 (specificity 85.9% and sensitivity 90.1%; p<0.001; AUC=0.934; 95% CI: 0.905-0.964 ) and 140.2 (specificity 83.5% and sensitivity 77.1%, p<0.001, AUC=0.821 95% CI: 0.767-0.874), respectively. Pretreatment NLR, PLR, CRP, and ESR levels were significantly higher than the posttreatment levels (all p<0.001). Correlation analysis revealed positive linear relations between pretreatment PLR and CRP (p=0.002, r=0.220), pretreatment PLR and ESR (p=0.018, r=0.171), pretreatment NLR and CRP (p<0.001, r=0.330), and pretreatment NLR and ESR (p=0.001, r=0.242). Multiple linear regression analysis revealed a 0.008 unit of increment of NLR per 1 unit increase in CRP levels (B=0.008; p<0.001; %95 CI=0.004-0.012). Conclusion: High NLR and PLR values accompanying thyrotoxicosis are both warning and helpful parameters for the diagnosis of SAT.