In a recently published study, Dr British Journal of PsychiatryResearchers assessed mortality in people with severe mental illness (SMI) after infection with coronavirus disease 2019 (COVID-19).
People with SMI have a 15- to 20-year life expectancy reduction compared to the general population, which has been consistently higher throughout the decades of the COVID-19 pandemic, regardless of race and ethnicity. Further, reports suggest that people with SMI are at increased risk of death from COVID-19 and other causes and, generally, at higher risk of hospitalization, with concerns that preexisting conditions may contribute to this (additional) risk.
The COVID-19 pandemic has exacerbated pre-existing disparities, particularly in terms of race/ethnicity. The intersection of race/ethnicity with SMI in COVID-19 outcomes remains clear. Furthermore, some ethnic minority groups have higher prevalence of multiple diseases, and there are concerns that these groups may experience delayed access to testing and vaccination. Furthermore, how SMI contributes to excess mortality risk after COVID-19 among ethnic minorities remains unknown.
Exploring determinants of post-Covid-19 mortality
In the current study, the researchers investigated whether mortality risk was higher among individuals with Covid-19 post-SMI and whether comorbidity and race/ethnicity had any effect on this risk. Information on family practice in Northern Ireland and England was obtained from the Arum database. Patients in this database broadly represent the United Kingdom (UK) population by age, sex, area-level deprivation and geographic distribution.
The SMI group included an SMI aged ≥ 5 years and a definite infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) between February 2020 and March 2021. They defined SMI as at least one record for bipolar disorder, schizoaffective disorder, schizophrenia, or other affective disorder with psychosis. The population control group included SARS-CoV-2-positive patients without a diagnosis of SMI.
Patients were followed until the date of death, termination of enrollment, or end of study. Notably, patients diagnosed with SMI after Covid-19 were excluded to reduce the risk of reverse causality. The study outcome was all-cause mortality. Covariate factors used to find determinants were demographic factors such as age, sex, ethnicity, area deprivation and geographical region. Area deprivation was a composite metric of area-level skills, education, income, crime, disability, health, housing, training and employment.
Data on intensive care unit (ICU) admissions, comorbidities with elevated COVID-19 risk, and corticosteroid drugs and immunological therapy were also included. Clinical variables included body mass index (BMI) and smoking status. Multivariable Cox proportional hazards regression was used to estimate differences in mortality between SMI and control groups.
Association of serious mental illness with post-Covid-19 mortality
The study included 7,146 patients in the SMI group and 653,024 controls. Patients in the SMI group were older than controls; The SMI group had higher proportions of patients with obesity and multimorbidity, current smokers and black African/Caribbean ethnicity. The study period spanned two COVID-19 waves.
The SMI group was more likely to die from COVID-19 than controls. Covid-19 deaths have increased in the UK since March/April 2020 and initially no casualties were observed in the first 60 days after Covid-19. Fewer deaths occurred between 60 and 90 days after infection. The researchers observed a sharp decline in survival probabilities in the SMI group during both Covid-19 waves, which was reproduced in covariate-adjusted survival probabilities.
Patients in the SMI group had an increased risk of all-cause mortality in sex- and age-adjusted models, which was consistent in models with further adjustment for smoking status, BMI, area deprivation, comorbidity, and race/ethnicity. There was no interaction between race/ethnicity and SMI.
Nevertheless, black African/Caribbean groups had a higher risk of death after COVID-19 than whites. Adjusted hazard ratios for all-cause mortality in the SMI group were 1.71 and 1.4 at the first and second waves, respectively, compared with controls. Notably, the researchers observed a statistical interaction between SMI and multimorbidity.
Data indicate that the additional, multiplicative effect of multimorbidity is significant in both groups but greater in controls. Sensitivity analyses, in which SMI and control patients were matched for number of multimorbid conditions, produced similar results to the primary analysis. In addition, results were comparable when SMI patients younger than 18 years were excluded.
Taken together, the study found that SMI patients experienced a substantially higher risk of death from COVID-19. Mortality increased sharply among SMI patients during the first wave of COVID-19 compared to controls. Both groups showed a steep decline in survival at about 400 days. Furthermore, the risk of all-cause mortality during the second wave was higher and longer in the SMI group than in controls.
Black people had a higher risk of dying from Covid-19 than white people. The results highlight the impact of multimorbidity on mortality risk in both groups. Overall, the study emphasized that SMI patients experienced significant disparities in mortality outcomes during COVID-19, magnified by multimorbidity.