Systemic immune-inflammation index and prognostic nutritional index in vestibular migraine and Meniere's disease: a retrospective comparison with healthy controls.

PURPOSE: To investigate whether the systemic immune-inflammation index (SII) and prognostic nutritional index (PNI) differ among patients with vestibular migraine (VM), patients with Meniere's disease (MD), and healthy controls, and to examine their associations with annual vertigo attack frequency and dizziness-related disability. METHODS: This retrospective record-based comparative study included 100 patients with definite VM, 100 patients with definite MD, and 100 healthy controls. For the VM and MD groups, SII and PNI were derived from routine interictal blood test results retrieved through retrospective screening of vertigo outpatient clinic records. Associations were evaluated using Spearman correlations; age and sex adjusted linear or Poisson regression, as appropriate. The Benjamini-Hochberg procedure was used to control the false discovery rate (FDR). RESULTS: PNI and SII did not differ among VM, MD, and control groups. Annual attack count was higher in VM than in MD (p = 0.004, q = 0.048). None of the 16 exploratory correlations remained significant after FDR correction. The nominal inverse correlation between PNI and attack count in MD (rho = - 0.221, p = 0.027) had q = 0.415, and neither PNI nor SII was independently associated with DHI or attack count in the adjusted models (all q ≥ 0.507). CONCLUSION: The predominantly negative findings do not support SII or PNI as stand-alone diagnostic or severity markers for interictal VM or MD, although small effects below the study's detection threshold cannot be excluded. Prospective studies with serial and attack-phase measurements are needed before any clinical role can be considered.