Elevated interictal plasma CGRP in Meniere's disease: A headache-independent candidate biomarker distinguishing Meniere's disease from vestibular migraine.

ObjectiveTo test whether interictal plasma or salivary calcitonin gene-related peptide (CGRP) distinguishes Ménière disease (MD) from vestibular migraine (VM), chronic migraine (CM), and healthy controls (HC).MethodsAdults with MD (n = 53), VM (n = 81), CM (n = 73), and HC (n = 59) provided morning interictal plasma and saliva. CGRP was measured in duplicate by ELISA. The primary contrast was plasma CGRP in MD versus VM; secondary analyses included multiplicity-corrected pairwise contrasts and ROC analysis.ResultsPlasma CGRP differed among groups (p < 0.001). Plasma CGRP in MD was higher than VM (75.2 [54.8-86.5] vs 37.1 [22.4-60.4] pg/mL; adjusted p < 0.001) and HC (37.7 [27.7-57.4] pg/mL; adjusted p < 0.001), but similar to CM (74.6 [49.6-101.6] pg/mL). Salivary CGRP differed overall (p = 0.001), driven mainly by CM versus HC, and did not separate MD from VM or HC. Plasma CGRP did not differ by headache status within MD. Plasma CGRP yielded an MD-versus-VM AUC of 0.805.ConclusionsInterictal plasma CGRP is elevated in MD relative to VM and HC, appearing independent of headache status. This assay-specific signal may support MD-versus-VM differentiation as a biological adjunct, but overlap with CM, absent severity correlations, and lack of external validation preclude disease-specific or stand-alone interpretation.