Comparative Diagnostic Utility of Systemic Inflammatory Indices Across Hyperthyroidism Subgroups

BACKGROUND/AIMS:In this retrospective study, we aimed to examine the diagnostic performance of systemic inflammation response index (SIRI), systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) parameters in terms of subgroups in hyperthyroidism cases. MATERIALS AND METHODS:A total of 191 patient files were included in the study; these patients had applied to the Internal Medicine Department of Fatih Sultan Mehmet Hospital and the Internal Medicine and Endocrinology Department of Florence Nightingale Ataehir Hospital were diagnosed with hyperthyroidism between January 2023 and June 2023.We evaluated age, gender, chronic drug usage, comorbidity, free T3, T4, anti-thyroid peroxidase (anti-TPO), anti-thyroglobulin antibody (anti-TG), thyrotropin receptor antibodies (TRAb), neutrophil, lymphocyte, platelet (PLT), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), NLR, PLR, SIRI, and SII parameters of the patients. RESULTS:Seventy-four patients (89.2%) had hashitoxicosis (HT), 28 patients (33.7%) had Graves' disease (GD), 16 patients (19.3%) had subacute thyroiditis (SAT), and 32 patients (38.6%) had overlapping entries in their files.Only the free T4 level was significantly correlated with hyperthyroidism (r=0.288,p<0.01).Correlations between hyperthyroidism and age, gender, chronic drug usage, comorbidity, free T3 and free T4, anti-TPO, anti-TG, TRAb, neutrophils, lymphocytes, PLT, CRP, ESR, NLR, PLR, SIRI, and SII were not statistically significant (p>0.05).The diagnostic performance of NLR, PLR, SIRI, and SII for hyperthyroidism was not statistically significant (p>0.05).Graves was significantly correlated with monocytes (r=0.240,p<0.05) and with SIRI (r=0.221,p<0.05).SAT was significantly correlated with CRP (r=0.574,p<0.01) and ESR (r=0.626,p<0.01).Overlap was significantly correlated with CRP (r=0.409,p<0.01) and with ESR (r=0.246,p<0.01).SIRI had a diagnostic performance of 63.5% for Graves (p<0.05).The diagnostic performance of all other blood parameters for HT, GD, SAT, and overlap groups was not significant (p>0.05).The area under the curve (AUC) for SIRI in GD was 0.635.At a SIRI cut-off value of 3.70, the sensitivity was 78.6% and the specificity was 52.7%. CONCLUSION:Although blood parameters lack sufficient diagnostic performance to distinguish hyperthyroidism subtypes, SIRI may have diagnostic performance specific to GD.Despite the low diagnostic performance, it would be beneficial to examine the diagnostic value of SIRI for GD in larger sample sizes and multicenter studies.SIRI should be interpreted as an adjunct biomarker rather than a diagnostic test.