Can Systemic Immune-Inflammation Index (SII) be a prognostic factor of Bell's palsy patients?

OBJECTIVE Recent studies showed that the neutrophil-to-lymphocyte ratio (NLR) and that platelet-to-lymphocyte ratio (PLR) can be used as inflammatory markers in Bell's palsy. In this study, the aim is to investigate a novel inflammatory index, the Systemic Immune-Inflammation Index (SII), defined as SII = platelets × neutrophils/lymphocytes, in Bell's palsy patients. STUDY DESIGN Retrospective. SETTING Clinical research center. PATIENTS The study included 88 Bell's palsy patients and 50 healthy controls. INTERVENTIONS Patients diagnosed with Bell's palsy from 2010 to 2019 in a university hospital and an age- and sex-matched healthy control group were included in the study retrospectively. A complete blood count was performed for all participants. Magnetic resonance imaging was applied for Bell's palsy patients for the exclusion of other diagnoses. MAIN OUTCOME MEASURES The CBC parameters were analyzed and hemoglobin, erythrocytes, leukocytes, neutrophils, lymphocytes, and platelet counts were measured. The PLR, NLR, and SII values were calculated with the formula. RESULTS The patient group had higher neutrophil counts and higher SII and NLR values than the control group (p < 0.05). Also, SII value is a prognostic factor in Bell's palsy in our study. CONCLUSIONS Bell's palsy has an inflammatory component. The SII value can indicate an inflammatory condition in these patients. It may be used as a marker and prognostic indicator in Bell's palsy.