Mortality among inpatients with bipolar disorders and COVID-19: a propensity score matching analysis in a national French cohort study.

Background: It remains unknown whether coronavirus disease 2019 (COVID-19) patients with bipolar disorders (BDs) are at an increased risk of mortality. We aimed to establish whether health outcomes and care differed between patients infected with COVID-19 with BD and patients without a diagnosis of severe mental illness.
Methods: We conducted a population-based cohort study of all patients with identified COVID-19 and respiratory symptoms who were hospitalized in France between February and June 2020. The outcomes were in-hospital mortality and intensive care unit (ICU) admission. We used propensity score matching to control for confounding factors.
Results: In total, 50 407 patients were included, of whom 480 were patients with BD. Patients with BD were 2 years older, more frequently women and had more comorbidities than controls without a diagnosis of severe mental illness. Patients with BD had an increased in-hospital mortality rate (26.6% v. 21.9%; p = 0.034) and similar ICU admission rate (27.9% v. 28.4%, p = 0.799), as confirmed by propensity analysis [odds ratio, 95% confidence interval (OR, 95% CI) for mortality: 1.30 (1.16-1.45), p < 0.0001]. Significant interactions between BD and age and between BD and social deprivation were found, highlighting that the most important inequalities in mortality were observed in the youngest [OR, 95% CI 2.28 (1.18-4.41), p = 0.0015] and most deprived patients with BD [OR, 95% CI 1.60 (1.33-1.92), p < 0.001].
Conclusions: COVID-19 patients with BD were at an increased risk of mortality, which was exacerbated in the youngest and most deprived patients with BD. Patients with BD should thus be targeted as a high-risk population for severe forms of COVID-19, requiring enhanced preventive and disease management strategies.