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Table 2 List of effectiveness and efficiency outcome measures

From: Vagus nerve stimulation as adjunctive therapy in patients with difficult-to-treat depression (RESTORE-LIFE): study protocol design and rationale of a real-world post-market study

Outcome measures Measurement details with clinician-rated and patient-reported scales
Primary outcome measure
 Rate of response Decrease of ≥50% in MADRS total score from baseline to 12 months post-implant. The MADRS is a physician-rated instrument to assess the severity of depressive symptoms during the past week [39, 40].
Secondary outcome measures
 Duration of response The difference between the first recorded date of post-baseline MADRS score when response is achieved (based on a decrease in baseline MADRS score of ≥50%) and the first date at which the MADRS score reaches a level of < 40% from baseline.
 Duration of response Change in MADRS score over time
 Duration of response Cumulative percentage of first-time responders (based on reduction in baseline MADRS score of ≥50%) and cumulative remission (based on MADRS score of ≤9 at any post-baseline visit) over time.
 Changes in mood, depression, and mania scores This will be based on changes in MADRS, QIDS-SR, and ASRM. The QIDS-SR questionnaire measures symptoms of mood and depression [41]. The ASRM measures the presence and severity of manic and hypomanic symptoms, specifically in patients diagnosed with bipolar disorder [42]. Note: ASRM is an optional assessment.
 Changes in quality of life and psychosocial impairment The WPAI:D questionnaire measures impairments in work and activities in depression [43]. The Q-LES-Q-SF scale measures the degree of enjoyment and satisfaction experienced during the past week [44]. The EQ-5D-5L questionnaire measures generic health status and quality of life [45].
 Changes in suicidality Based on Item Number 10 of MADRS and Item Number 12 of QIDS-SR.
 Changes in antidepressant treatments This will include data on drug dosage and type of antidepressant medications, and duration and intervals of maintenance ECT, rTMS, and/or psychotherapy.
 Changes in cognition THINC-it® Tool includes the 5-item PDQ-5, in addition to 4 traditional cognitive assessments which have been reconfigured for computer-based administration. Thus, it assesses both a patient’s subjective assessment as well as key objective measures of cognitive function [46]. Note: THINC-it is an optional assessment.
 Changes in anxiety The GAD-7 measures severity of generalized anxiety disorder [47]. Note: GAD-7 is an optional assessment.
Exploratory outcome measures
 Changes in positive affect, negative affect, hedonic tone, cognitive functioning, overall functioning, meaningfulness of life, and happiness with adjunctive VNS treatment The LAPS questionnaire assesses negative affect, positive affect, hedonic tone, and meaningfulness of life [48].
 Healthcare resource utilization analysis Healthcare utilization data will be used to assess the main sources of resource utilization associated with DTD management per patient who have been subsequently treated with VNS Therapy. The collected data will include the number of depression-related emergency room visits leading to hospitalizations, antidepressant medication usage, and adjunctive antidepressant treatments before and after the start of VNS Therapy.
  1. The patient-completed self-report assessments will be completed by participants who are able to complete the assessments with minimal assistance
  2. The ASRM, THINC-it Tool, and GAD-7 are optional assessments that will be completed at selected and interested sites only, and participants will be selected to complete the assessments based on the study physician’s clinical judgment