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Adjunctive vagus nerve stimulation improves quality of life in treatment-resistant depression

Vagus nerve stimulation plus treatment as usual significantly improved quality of life in patients with treatment-resistant depression compared with patients receiving treatment as usual alone, study findings showed.

“During the course of studying [vagus nerve stimulation] in [treatment-resistant depression] and epilepsy, the treatment has ... been hypothesized to positively affect factors beyond depression, including anxiety and alertness, pain perception and cognition,” Charles R. Conway, MD, of the department of psychiatry at Washington University School of Medicine, and colleagues wrote. “The effects of [vagus nerve stimulation] on long-term quality of life have yet to be examined.”

The investigators compared treatment as usual with any antidepressant medication vs. vagus nerve stimulation treatment plus treatment as usual in 599 patients with treatment-resistant depression over the course of 5 years. Specifically, they examined participants’ self-reported quality of life measured via questionnaire and the antidepressant efficacy measured via the Montgomery-Asberg Depression Rating Scale of two treatments.

In total, 328 patients received adjunctive vagus nerve stimulation and 271 received treatment as usual. Treatment with adjunctive vagus nerve stimulation demonstrated a significant quality of life advantage over treatment as usual, which began at 3 months and was sustained through 5 years. Patients receiving adjunctive vagus nerve stimulation experienced clinically meaningful improvement in quality of life, but those receiving treatment as usual alone did not.

Exploratory post hoc subanalysis comparing quality of life functional domain change showed that treatment as usual plus vagus nerve stimulation benefited multiple domains, including overall well-being, improvement in perceived functional ability, household activities and leisure activities.

The individual model estimated that patients receiving adjunctive vagus nerve stimulation could achieve a clinically meaningful increase in quality of life score of 11.89 on average when the depression score dropped as low as 34% from baseline. However, this level is below the “standard” 50% drop typically used to define antidepressant treatment response, according to the researchers.

“The findings suggest that our ‘standard’ measure of a treatment’s success — a 50% reduction in depressive symptoms — may not be an adequate measure in patients with [treatment-resistant depression],” Conway and colleagues wrote. “This suggestion is particularly compelling, as the population of depressed patients studied in this trial was more ill than the reference group.” – by Savannah Demko

Disclosures: Conway reports past support from Bristol-Myers Squibb and LivaNova, and current support from the Barnes-Jewish Hospital Foundation, NeoSync Inc, NIMH, the Stanley Medical Research Institute, The August Busch IV Foundation and The Taylor Family Institute for Innovative Psychiatric Research. He reports previous speaking fees from Bristol-Myers Squibb and Otsuka, and consulting for LivaNova. He is employed by the John Cochran Veterans Administration Hospital. Please see the study for all other authors’ relevant financial disclosures.