The Systemic Inflammatory Response Index as a Novel Diagnostic Indicator for Bell’s Palsy

<b>Aims/Background</b> The systemic inflammatory response index (SIRI), an emerging hematological marker of inflammation, has shown promise as a promising biomarker for a variety of inflammatory conditions. This study aims to explore the diagnostic role of SIRI in Bell's palsy (BP). <b>Methods</b> For this retrospective study, 73 people diagnosed with BP between January 2021 and December 2023 were recruited, along with 73 healthy controls who were age- and sex-matched. The SIRI and other blood inflammatory markers, including the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR), were determined for all participants, by enumerating their peripheral blood cell counts. Facial nerve function was assessed upon admission and after one month of treatment using the House-Brackmann Facial Nerve Grading System (H-B). According to this system, patients with an H-B grade of 1-2 are considered recovered, while those with an H-B grade of 3-6 are regarded as not recovered. <b>Results</b> The SIRI (0.94 vs 0.48, <i>p</i> < 0.001), SII (480.3 vs 329.12, <i>p</i> < 0.001), NLR (2.42 vs 1.41, <i>p</i> < 0.001), and PLR (141.05 vs 117.28, <i>p</i> = 0.001) showed a significant increase in the BP group compared to the control group. The receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) for SIRI was higher than those for SII, NLR, and PLR, respectively. Upon one-month follow-up, significant differences in the values of SIRI, SII, and NLR were observed between the favorable prognosis group and the poor prognosis group (SIRI: 1.07 vs 0.87, <i>p</i> = 0.011; SII: 647.85 vs 422.11, <i>p</i> = 0.005; NLR: 3.31 vs 2.11, <i>p</i> = 0.013). The AUC of ROC curve for SIRI was found to be lower than that of SII but higher than that of NLR. <b>Conclusion</b> The SIRI has the potential to be an important BP diagnostic and prognostic marker.