compared with those without a psychiatric diagnosis, according to the results of the largest study of its kind to date.
These findings, the investigators noted, highlight the need to prioritize vaccination in patients with preexisting mental health disorders.
“We have proven beyond a shadow of a doubt that there are increased risks” among psychiatric patients who get COVID-19, study investigator Livia De Picker, MD, PhD, psychiatrist and postdoctoral researcher, University Psychiatric Hospital Campus Duffel and University of Antwerp (Belgium), told this news organization.
“Doctors need to look at these patients the same way they would other high-risk people, for example those with diabetes or chronic obstructive pulmonary disease,” all of whom should be protected against COVID-19, Dr. De Picker added.
The study was published online July 15, 2021, in Lancet Psychiatry.
Risk by mental illness type
The systematic review included 33 studies from 22 countries that reported risk estimates for mortality, hospitalization, and ICU admission in patients with confirmed SARS-CoV-2 infection. The meta-analysis included 23 of these studies with a total of 1.47 million participants. Of these, 43,938 had a psychiatric disorder.
The primary outcome was mortality after COVID-19. Secondary outcomes included hospitalization and ICU admission after COVID-19. Researchers adjusted for age, sex, and other covariates.
Results showed the presence of any comorbid mental illness was associated with an increased risk for death after SARS-CoV-2 infection (odds ratio, 2.00; 95% confidence interval, 1.58-2.54; P < .0001).
When researchers stratified mortality risk by psychiatric disorder type, the most robust associations were for psychotic and mood disorders. Substance use disorders, intellectual disabilities, and developmental disorders were associated with higher mortality only in crude estimates. There was no increased death risk associated with anxiety disorders.
“That there are differences between the various types of disorders was an interesting finding,” said Dr. De Picker, adding that previous research “just lumped together all diagnostic categories.”
Potential mechanisms
The study did not explore why psychiatric illness raise the risk for death in the setting of COVID-19, so potential mechanisms are purely speculative. However, the investigators believe it may reflect biological processes such as immune-inflammatory alterations.
Psychotic disorders and mood disorders in particular, are associated with immune changes, including immunogenetic abnormalities, raised cytokine concentrations, autoantibodies, acute-phase proteins, and aberrant counts of leukocyte cell types, said Dr. De Picker.
She likened this to elderly people being at increased risk following COVID-19 because their immune system is compromised and less able to fight infection.
There are likely other factors at play, said Dr. De Picker. These could include social isolation and lifestyle factors like poor diet, physical inactivity, high alcohol and tobacco use, and sleep disturbances.
In addition, psychiatric patients have a higher prevalence of comorbidities including diabetes, cardiovascular disease, and respiratory disease, which could also play a role.
The increased mortality might also reflect reduced access to care. “Some of these patients may be living in difficult socioeconomic conditions,” said Dr. De Picker.
She noted that, while the in-hospital mortality was not increased, the risk was significantly increased in samples that were outside of the hospital. This reinforces the need for providing close monitoring and early referral to hospital for psychiatric patients with COVID-19.
Mortality varied significantly among countries, with the lowest risk in Europe and the United States. This difference might be attributable to differences in health care systems and access to care, said Dr. De Picker.
Overall, the risk for hospitalization was about double for COVID patients with a mental illness, but when stratified by disorder, there was only a significantly increased risk for substance use and mood disorders. “But mood disorders were not even significant any more after adjusting for age, sex, and comorbid conditions, and we don’t see an increased risk for psychotic disorders whereas they had the highest mortality risks,” said Dr. De Picker.