Major adverse cardiovascular events following electroconvulsive therapy in depression: A register-based nationwide Swedish cohort study with 1-year follow-up

Background: The cardiovascular response during electroconvulsive therapy (ECT) could induce major adverse cardiovascular events (MACE) in the short-term, while reduced depression could decrease the risk of MACE in the long-term. The balance between these potential effects has not been thoroughly investigated.

Methods: This nationwide, registry-based cohort study included all patients admitted to Swedish hospitals due to moderate or severe unipolar depression between 2011 and 2018. Patients were divided into an ECT group and a non-ECT group, and followed for 1 year. Patients were matched by risk factors for cardiovascular disease by propensity score matching. Cox regression was used to examine the association between ECT and MACE.

Results: Out of a total of 28 584 inpatients, 5476 patients who had received ECT were matched to 5476 non-ECT patients. ECT was associated with reduced risk of MACE within 90 days and 1 year. Within 1 year after admission, a total of 127 patients (2.3%) in the non-ECT group and 82 patients (1.4%) in the ECT group had at least one MACE (hazard ratio [HR], 0.65; 95% confidence interval, 0.49-0.85).

Limitations: Real-life observational studies carry risk for residual confounding.

Conclusions: ECT in patients hospitalized for depression was not associated with any significant short-term risks of cardiovascular events. Instead, ECT was associated with a reduced risk of MACE within 1 year after admission compared with patients not treated with ECT. This association may be explained by reduced depressive symptoms after ECT, improved risk factor management in the ECT-group or by residual confounding by indication.