Adjunctive VNS delivers better outcomes than treatment as usual in moderate to severe depression
Adjunctive vagus nerve stimulation (VNS) improves long-term outcomes compared with treatment as usual in patients with treatment-resistant depression, reports a recent study.
Researchers conducted a 5-year, prospective, open-label, nonrandomized, observational registry study at 61 US sites, which included 795 patients who were experiencing a major depressive episode (unipolar or bipolar depression) of at least 2 years’ duration or had three or more depressive episodes (including the current one), and who had failed four or more depression treatments (including electroconvulsive therapy [ECT]). Those with a history of psychosis or rapid-cycling bipolar disorder were excluded.
Response rate, defined as a decrease of ≥50 percent in baseline Montgomery-Åsberg Depression Rating Scale (MADRS) score at any postbaseline visit during the study period, was the primary efficacy measure. Secondary efficacy measures included remission.
Patients were diagnosed with chronic moderate to severe depression at baseline (mean MADRS scores, 29.3 for the treatment-as-usual group and 33.1 for the adjunctive VNS group).
Better clinical outcomes were observed in the adjunctive VNS group compared with the treatment-as-usual group. Moreover, the adjunctive VNS group had a significantly higher 5-year cumulative response rate (67.6 vs 40.9 percent) and a significantly greater remission rate (cumulative first-time remitters, 43.3 vs 25.7 percent).
In a subanalysis, patients with a history of response to ECT included in the adjunctive VNS group had a significantly higher 5-year cumulative response than those in the treatment-as-usual group (71.3 vs 56.9 percent). There was a similar significant response differential among ECT nonresponders (59.6 vs 34.1 percent).
“This registry represents the longest and largest naturalistic study of efficacy outcomes in treatment-resistant depression, and it provides additional evidence that adjunctive VNS has enhanced antidepressant effects compared with treatment as usual in this severely ill patient population,” researchers said.