Background: The subset of admitted Major Depressive Disorder (MDD) patients with treatment-resistant depression (TRD) may be associated with incremental economic burden compared with other MDD patients. This study aimed to characterize and evaluate healthcare resource use, admission measures, and costs in these two groups.

Methods: Patients aged ≥18 years with a diagnosis of MDD admitted between 1/1/2012 and 9/30/2015 were identified from the Premier Perspective database. The first admission was defined as the index hospitalization. Two MDD patient cohorts were identified based on each patient’s TRD status (yes vs. no). MDD patients with TRD were defined based on the presence of any of the following: electroconvulsive therapy, transcranial magnetic stimulation, vagus nerve stimulation, receipt of Symbyax treatment, or any anti-depressants and one of four antipsychotics (aripiprazole, brexpiprazole, olanzapine, quetiapine) during day 1 or 2 of the index hospitalization. Patient demographics and clinical characteristics, index hospital length of stay (LOS), and associated hospital costs were compared between the two cohorts. Hospital readmission rates and associated healthcare resource use and hospital costs during the 6-months post-index hospitalization were also compared with both bivariate statistics and multivariable Cox regression that controlled for key patient characteristics.

Results: Among the total number of patients identified with MDD (n= 204,575), 22% (n= 45,127) met TRD status. Patients with TRD were older (mean age: 46 vs. 43, p<0.0001) and were more likely to be Medicare covered (28% vs. 21%, p<0.0001) than patients without TRD. Mean index hospital LOS was 37% longer for patients with TRD vs. without TRD (7.4 vs. 5.4 days; p<0.0001) and mean index total hospital cost was 43% higher for patients with TRD vs. without TRD ($8,694 vs. $6,082, p<0.0001). After controlling for key patient characteristics, readmission risk was 22% higher in patients with TRD vs. without TRD (HR=1.22; 95% CI: 1.19-1.25).

Conclusions: This analysis suggests that hospitalized patients with TRD, relative to those without TRD, experience incremental healthcare resource utilization (HRU). Identification of more effective treatment and care continuity may reduce this additional burden and potentially reduce readmission rates.