A retrospective analysis of ketamine intravenous therapy for depression in real-world care settings.

Summary

In a retrospective analysis of 537 patients receiving ketamine intravenous therapy for depression in 178 U.S. community practices, 53.6% showed a response (at least 50% reduction in depression scores) and 28.9% achieved remission within 14-31 days after the induction phase. Among patients with suicidal ideation at baseline, 73.0% reported a reduction. A small portion of patients worsened: 8.4% experienced increased depressive symptoms and 6.0% reported increased suicidal ideation. Response rates were similar across levels of baseline depression severity. Patients who responded had about an 80% chance of sustaining that response at 4 weeks and about 60% at 8 weeks, even without maintenance infusions.

Study at a glance

Abstract

BACKGROUND Outcomes of ketamine intravenous therapy (KIT) for depression in real-world care settings have been minimally evaluated. We set out to quantify treatment response to KIT in a large sample of patients from community-based practices. METHODS We retrospectively analyzed 9016 depression patients who received KIT between 2016 and 2020 at one of 178 community practices across the United States. Depression symptoms were evaluated using the Patient Health Questionnaire-9 (PHQ-9). The induction phase of KIT was defined to be a series of 4-8 infusions administered over 7 to 28 days. RESULTS Among the 537 patients who underwent induction and had sufficient data, 53.6% of patients showed a response (≥ 50% reduction in PHQ-9 score) at 14-31 days post-induction and 28.9% remitted (PHQ-9 score drop to < 5). The effect size was d = 1.5. Among patients with baseline suicidal ideation (SI), 73.0% exhibited a reduction in SI. A subset (8.4%) of patients experienced an increase in depressive symptoms after induction while 6.0% of patients reported increased SI. The response rate was uniform across 4 levels of baseline depression severity. However, more severe illness was weakly correlated with a greater drop in scores while remission status was weakly inversely correlated with depression severity. Kaplan-Meier analyses showed that a patient who responds to KIT induction has approximately 80% probability of sustaining response at 4 weeks and approximately 60% probability at 8 weeks, even without maintenance infusions. CONCLUSION KIT can elicit a robust antidepressant response in community clinics; however, a small percentage of patients worsened.