From "ECT Reduces Suicide Risk in Severe Depression: New Data" (MedScape)
In the matched sample, ECT was associated with a significantly decreased risk for suicide within 12 months compared with non-ECT (hazard ratio [HR] 0.72; 95% CI, 0.52 - 0.99). About 1.1% of the ECT group and 1.6% in the non-ECT group died of suicide within 12 months.
Researchers also carried out an "episode based" analysis, which included all hospitalizations. Nordenskjöld explained that some patients who didn't have ECT on first hospitalization received it during subsequent admissions and vice versa. Here, the suicide risk was reduced in the ECT group but not significantly (HR, 0.82; 95% CI, 0.65 - 1.03).
I'm not sure I understand the meaning of "episode-based analysis" here. Does it mean, for instance, that if a person received ECT on his first hospitalization, but then was hospitalized 2 years later, this time without ECT, then discharged, and committed suicide within 12 months of this second discharge -- then this would also count as "suicide in the ECT group"? Despite the fact that the patient did not receive ECT during this latest hospitalization?
I tried reading the described publication, but also failed to understand the meaning of the phrase.
Publication: Electroconvulsive Therapy and the Risk of Suicide in Hospitalized Patients With Major Depressive Disorder (JAMA Network Open, 2021)