Equal remission rates and reduced length of hospital stay with twice-daily repetitive transcranial magnetic stimulation (rTMS) for major depression - A large naturalistic retrospective cohort association study.

OBJECTIVES: Repetitive transcranial magnetic stimulation (rTMS) is a level 1a evidence-based treatment for major depression, but high cost of care and limited effectiveness in naturalistic cohorts have been lingering criticisms. This naturalistic, retrospective cohort analysis compares the effect of once and twice daily treatment protocols of rTMS using quality assurance data collected at an Australian private psychiatric hospital.

METHODS: A total of 210 inpatients self-selected into two groups receiving up to 30 sessions of either daily (n = 101) or twice daily (n = 109) 10 Hz rTMS to the left dorsolateral prefrontal cortex (DLPFC). The a priori primary outcome measure was remission rate as measured by pre and post treatment HAMD-17 scores. Length of hospital stay was a secondary post hoc outcome adopted due to the importance to cost of acute psychiatric care.

RESULTS: Remission rates were similar across groups, with 44.9% and 45.4% for twice daily and daily rTMS groups respectively, although these may be confounded by patient expectations, other treatments and medication changes given the naturalistic setting. The length of hospital stay was 10.11 days and 18.44 days for twice daily and daily rTMS respectively - the twice daily rTMS length of hospital stay was 45.1% shorter 95% CI [38.7% - 51.56%]. Dropout rates were high; Twenty-seven (24.77%) twice daily participants dropped out before 20 sessions were completed, and 35 (34.65%) of daily participants.

CONCLUSIONS: Twice daily 10 Hz left sided rTMS remission outcomes were similar to traditional once daily rTMS but required a shorter length of hospital stay. This finding has substantial cost of care implications. If these findings are independently replicated, twice daily rTMS may become the standard of care for inpatient rTMS.