The Impact of High Glycated Hemoglobin A1c on Prognosis in Patients with Bell's Palsy: A Propensity Score Matchingatched Analysis.

Background: Glycated hemoglobin A1c (HbA1c) is an indicator of blood glucose levels, but the impact of hyperglycemia on Bell's palsy (BP) remains unclear. This study aims to assess the influence of high and low HbA1c levels on the prognosis of patients with BP. Methods: This monocentric, retrospective study included 712 patients with BP, divided into 103 patients with HbA1c ≥ 6.5% and 609 patients with HbA1c < 6.5%. Receiver operating characteristic curve analysis was used to evaluate the main factors affecting HbA1c levels. Propensity score matching (PSM) was further utilized to avoid selection bias and disproportionate distributions of confounding factors between the 2 groups. The House-Brackmann (H-B) facial nerve grading system was employed to assess the severity of facial motor dysfunction. Results: Analysis showed that high HbA1c patients were older, had higher body mass index, less frequently suffered from dysgeusia, and more often had hypertension (P < .05). According to the area under the curve, age had the greatest impact on HbA1c levels (95% CI=0.748-0.803, P <.001). After PSM 1 : 1 matching, there was no statistical difference in initial H-B grade between the 2 groups, but there was a statistical difference in final H-B grade (P = .023), indicating a worse prognosis for patients with BP in the high HbA1c group. Conclusion: The study, after controlling for confounding factors, showed that patients with BP and high HbA1c have a worse prognosis, suggesting that controlling blood glucose levels has a positive significance for the recovery of patients with BP.