Early electroconvulsive therapy in patients with bipolar depression: A propensity score-matched analysis using a nationwide inpatient database.

Objectives: Electroconvulsive therapy (ECT) is a widely used treatment for bipolar depression; however, evidence of its effectiveness is not sufficient. This study therefore aimed to evaluate whether early ECT is associated with reduced length of hospital stay.

Methods: In this retrospective cohort study using the Japanese Diagnosis Procedure Combination database, we identified patients admitted for bipolar depression between April 2010 and March 2018. The primary outcome was length of hospital stay, and the secondary outcome was clinical outcomes and total hospitalization costs. Propensity score-matched analyses were performed to compare the outcomes between patients who received ECT within 8 days of admission (early ECT group) and those who did not (control group).

Results: We identified 5941 eligible patients, comprising 219 in the early ECT group and 5722 in the control group. After 1:4 propensity score matching, patients in the early ECT group had significantly shorter lengths of hospital stay than those in the control group (53 days in the early ECT group and 73 days in the control group; difference: -20.2 days; 95 % confidence interval: -29.2 to -11.2 days). There was no significant difference in total hospitalization costs between the two groups. In-hospital mortality and fatal complications were rare in both groups. The result was similar in the sensitivity analysis using inverse probability of treatment weighting.

Limitations: Our study was limited by retrospective design and the possibility of unmeasured confounders.

Conclusions: Early ECT was associated with reduced length of hospital stay without increasing total hospitalization costs in patients with bipolar depression.