The effectiveness of non-invasive vagus nerve stimulation in migraine management: a meta-analysis of randomized controlled trials.

BACKGROUND: Non-invasive vagus nerve stimulation (nVNS) has emerged as a potential non-pharmacological intervention for migraine. This systematic review and meta-analysis of randomized controlled trials (RCTs) evaluated its efficacy for both acute and preventive migraine treatment. METHODS: This review was conducted according to PRISMA and registered in PROSPERO (CRD420261347799). PubMed, Cochrane Central, Embase, CNKI, VIP, and Wanfang were searched from inception to February 19, 2026, to identify RCTs of nVNS for migraine. The primary outcomes were monthly headache days, monthly acute medication use, and headache pain intensity. Continuous outcomes were synthesized as mean differences (MDs), and dichotomous outcomes as odds ratios (ORs), with 95% confidence intervals (CIs). Fixed- or random-effects models were applied according to outcome type and statistical heterogeneity, and random-effects sensitivity analyses were conducted for continuous primary outcomes to account for expected clinical heterogeneity. Risk of bias was assessed using the original Cochrane Risk of Bias tool, and certainty of evidence was evaluated using GRADE. RESULTS: Seven RCTs involving 917 patients with migraine were included. Meta-analysis showed that nVNS significantly reduced monthly headache days (MD = -1.52, 95% CI - 1.86 to -1.18, p < 0.001), monthly acute medication days (MD = -1.18, 95% CI - 1.72 to -0.63, p < 0.001), and headache pain intensity (MD = -0.97, 95% CI - 1.30 to -0.64, p < 0.001), with low heterogeneity across these outcomes. Exploratory overall estimates for acute treatment outcomes also favored nVNS for pain-free and pain-relief responses within 2 h, although these findings were interpreted cautiously because repeated time-point data from the same trials may be correlated. Overall risk of bias was low. GRADE certainty was high for monthly headache days and monthly acute medication days, and moderate for headache pain intensity, acute treatment outcomes, and adverse events. CONCLUSION: nVNS may reduce monthly headache days, acute medication use, and headache pain intensity, while also improving acute pain-free and pain-relief responses within 2 h in patients with migraine. It may represent a promising non-pharmacological option for migraine treatment and prevention, although further high-quality studies are needed to confirm its long-term efficacy and safety. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD420261347799, identifier: CRD420261347799.