Vagus nerve stimulation: An update of currently registered clinical trials on ClinicalTrials.gov

Background: Vagus nerve stimulation (VNS) is currently approved for conditions such as drug-resistant epilepsy and stroke with promising results. In addition, it is also being investigated for many other conditions. The goal of this study is to review the scope of VNS clinical trials. Methods: We conducted a retrospective review of active and completed clinical trials using ClinicalTrials.gov, with “Vagus Nerve Stimulation” as the search term. The number of studies taking place over time was assessed using Pearson correlation coefficient. Results: An examination of ClinicalTrials.gov revealed 440 clinical trials, with 346 meeting our inclusion criteria. The number of VNS clinical trials increased annually from 2000 to 2024, demonstrating exponential growth after 2015 ( P < 0.001, R 2 = 0.924). Of these, 42.5% were completed, with published results being available for 9.8% of the completed trials. Completed trials were predominantly from the United States, spanning various conditions including a wide variety of disorders such as cardiovascular diseases ( n = 38), chronic pain disorders ( n = 31), gastrointestinal disorders ( n = 24), autoimmune disorders ( n = 23), neurodegenerative diseases ( n = 19), COVID-19 ( n = 13) and diabetes ( n = 11). Among the included trials, 86% were non-invasive with 91% of trials with results reporting improvements in symptoms. Conclusion: This increasing number of trials assessing a wide breadth of clinical disorders suggests the promising future of VNS as from the currently approved treatments. Physicians should familiarize themselves with these results and potentially upcoming indications for VNS.