Role of medical comorbidity in the association between psychiatric disorders and mortality among patients with COVID-19.

We examined whether excess chronic medical comorbidity mediated excess COVID-19 inpatient mortality among people with mental disorders in the early phase of the pandemic, a question with important implications for public health and clinical decision-making. Using records of 2599 COVID-19 hospitalized patients, we conducted a formal causal mediation analysis to estimate the extent to which chronic comorbidity mediates the association between mental disorders and COVID-19 mortality. The Odds Ratio (95% CI) for Natural Indirect Effect and Controlled Direct Effect were 1.07(1.02, 1.14) and 1.40 (1.00, 1.95), respectively, suggesting that a large proportion of excess COVID-19 mortality among people with mental disorders may be explained by factors other than comorbidity.