P1: Dosing and treatment outcomes of rTMS for treatment-resistant depressed older adults in a naturalistic outpatient clinic population.

Abstract

Introduction:

Repetitive transcranial magnetic stimulation (rTMS) is an effective, safe, and well-tolerated option for treatment-resistant depression (TRD). The minimal medical and cognitive side effects are advantages of rTMS for all patients. However, the majority of rTMS studies in older adults are notable for underdosing rTMS relative to the corresponding FDA-protocol, as noted by recent international meta-analyses. This study utilizes the standardized rTMS FDA protocol and compares the response rates between older adult and non-older adult patients in a TRD clinic in Atlanta, Georgia with depressive symptoms as the primary outcome and anxiety symptoms as the secondary outcome.

Methods:

This retrospective chart review of patients who received rTMS between March 2017 to June 2022 used descriptive statistics to compare treatment parameters and dropout rates between older adult and non-older adult patients. A 2 x 3 repeated-measures analysis of variance (ANOVA) analyzed changes in self-reported depression and anxiety symptom severity throughout treatment course (baseline, treatment midpoint, and final treatment) between the two groups.

Results:

Eighty-nine patients were included for analysis: Group 1: >55 years old (n= 42; M= 66.48, sd= 6.16; 71% female), and Group 2: <55 years old (n = 47; M= 37.40, sd= 9.13; 60% female). All patients received at least 3000 pulses per session, with 85.71% of patients completing the FDA protocol in Group 1 and 85.11% of patients completing in Group 2. A >50% improvement in depression scores at the end of treatment were seen in 38.1% of patients in Group 1 and 31.9% of patients in Group 2. Both groups demonstrated significant within-group reductions of depression throughout treatment (ps < .001). A smaller subset of patients completed an anxiety questionnaire. Forty percent in Group 1 (n=24) and 33.3% in Group 2 (n=25) showed a >50% improvement in anxiety scores by end of treatment. Both groups demonstrated significant within-group reductions of anxiety throughout treatment (ps < .001). The between groups’ difference for change in depression and anxiety scores was not statistically significant.

Conclusion:

With FDA protocol dosing, older and non-older patients have consistent response and tolerability. While overall response rates were slightly lower than reported standardized clinical trials, our real-world sample highlights the effectiveness of rTMS for patients, including adults over 55, treated in an unselected, naturalistic outpatient sample.