Neuropsychiatric Disease and Treatment (Feb 2019)
Durability of symptomatic responses obtained with adjunctive vagus nerve stimulation in treatment-resistant depression
Abstract
Arun Kumar,1 Mark T Bunker,1 Scott T Aaronson,2 Charles R Conway,3 Anthony J Rothschild,4,5 Giacomo Mordenti,6 Augustus J Rush7,8 1LivaNova USA PLC, Houston, TX, USA; 2Department of Clinical Research, Sheppard Pratt Health System, Baltimore, MD, USA; 3Department of Psychiatry, Washington University School of Medicine in St Louis, St Louis, MO, USA; 4Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA, USA; 5Department of Psychiatry, UMass Memorial Medical Center, Worcester, MA, USA; 6LivaNova PLC, London, UK; 7Department of Psychiatry and Behavioral Sciences, National University of Singapore, Singapore; 8Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA Objective: To compare the durations of response achieved with adjunctive vagus nerve stimulation (VNS + TAU) vs treatment as usual (TAU) alone in treatment-resistant depression (TRD) over a 5-year period in the TRD registry. Materials and methods: Data from 271 participants on TAU and 328 participants on VNS + TAU were analyzed. Response was defined as ≥50% decrease in baseline Montgomery–Åsberg Depression Rating Scale (MADRS) score at postbaseline visit and was considered retained until the decrease was <40%. MADRS was obtained quarterly in year 1 and biannually thereafter. Time-to-events were estimated using Kaplan–Meier method and compared using log-rank test. HR was estimated using Cox proportion hazard model. Results: In the VNS + TAU arm, 62.5% (205/328) of participants had a first response over 5 years compared with 39.9% (108/271) in TAU. The time to first response was significantly shorter for VNS + TAU than for TAU (P<0.01). For responders in the first year, median time to relapse from first response was 10.1 months (Q1=4.2, Q3=31.5) for VNS + TAU vs 7.3 months (Q1=3.1, Q3=17.6) for TAU (P<0.01). HR=0.6 (95% CI: 0.4, 0.9) revealed a significantly lower chance for relapse in VNS + TAU. Probability of retaining first response for a year was 0.39 (0.27, 0.51) for TAU and 0.47 (0.38, 0.56) for VNS + TAU. Timing of the onset of the response did not impact the durability of the response. Conclusion: VNS therapy added to TAU in severe TRD leads to rapid onset and higher likelihood of response, and a greater durability of the response as compared to TAU alone. Keywords: depressive disorder, treatment-resistant depression, vagus nerve stimulation, longitudinal study, durability of response
