Researchers report outcome predictors of repetitive transcranial magnetic stimulation for MDD

Measures of depression symptom severity, employment status and refractoriness appeared to predict outcomes of repetitive transcranial magnetic stimulation, or rTMS, among individuals with major depressive disorder, according to an analysis of a randomized noninferiority trial published in EClinicalMedicine.

“The degree of response to [rTMS] is quite variable across individuals, with previous studies showing a bimodal or trimodal distribution of outcomes,” Alisson P. Trevizol, MD, PhD, of the department of psychiatry at University of Toronto, and colleagues wrote. “Variations in the degree of response to rTMS have been attributed to several patient-specific, illness-specific and treatment-modality-specific factors. To increase the efficacy and effectiveness of rTMS for MDD, studies have attempted to identify replicable and quantifiable predictors of therapeutic outcomes.”

However, these prior studies were limited by small sample sizes or pooled data from previous trials, which has resulted in no baseline demographic variables as clear predictors of therapeutic outcome.

In the current study, the investigators sought to improve patient selection by identifying clinical predictors of remission following a course of rTMS delivered to the left dorsolateral prefrontal cortex. They conducted exploratory analyses using data from a large, randomized, noninferiority trial that compared standard 10 Hz and intermittent theta burst stimulation (iTBS) for MDD treatment. In a logistic regression model, they assessed the association of individual variables with remission. They used the c-index to carry out model discrimination to assess model optimism.

The researchers analyzed data of 199 patients who received iTBS and 189 patients who received the 10 Hz intervention. Results showed an association between higher baseline severity of both depressive and anxiety symptoms and a lower chance of achieving remission after rTMS (Hamilton Depression Rating Scale OR = 0.64; 95% CI, 0.46-0.88; Brief Symptom Inventory for Anxiety OR = 0.76; 95% CI, 0.6-0.98). Current employment positively predicted remission (OR = 1.69; 95% CI, 1.06-2.7), and greater number of treatment failures was associated with lower odds of achieving remission (OR = 0.51; 95% CI, 0.27-0.98). The researchers observed a nonlinear effect of age and remission and reported a c-index for the fitted model of 0.687.

“Sham-controlled studies are necessary to better understand the relationship between potential predictors of remission and the treatment-specific effects of the rTMS interventions,” the researchers wrote. “Complementary biological and clinical variables are likely to aid in the development of better predictive models.” – by Joe Gramigna

Disclosures: Trevizol reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.