key: cord-0844186-xfw06sjx
authors: Passos-Castilho, Ana Maria; Labbé, Annie-Claude; Barkati, Sapha; Luong, Me-Linh; Dagher, Olina; Maynard, Noémie; Tutt-Guérette, Marc-Antoine; Kierans, James; Rousseau, Cecile; Benedetti, Andrea; Azoulay, Laurent; Greenaway, Christina
title: Outcomes of hospitalized COVID-19 in Canada: impact of ethnicity, migration status, and country of birth
date: 2022-04-13
journal: J Travel Med
DOI: 10.1093/jtm/taac041
sha: 2ae444cd1e186b23a01d8b824b791047e0ca87d5
doc_id: 844186
cord_uid: xfw06sjx

Background: Ethnoracial groups in high-income countries have a 2-fold higher risk of SARS-CoV-2 infection, associated hospitalizations, and mortality than Whites. Migrants are an ethnoracial subset that may have worse COVID-19 outcomes due to additional barriers accessing care, but there are limited data on in-hospital outcomes. We aimed to disaggregate and compare COVID-19 associated hospital outcomes by ethnicity, immigrant status and region of birth. Methods: Adults with community-acquired SARS-CoV-2 infection, hospitalized March 1–June 30, 2020, at four hospitals in Montréal, Quebec, Canada, were included. Age, sex, socioeconomic status, comorbidities, migration status, region of birth, self-identified ethnicity [White, Black, Asian, Latino, Middle East/North African], intensive care unit (ICU) admissions and mortality were collected. Adjusted hazard ratios (aHR) for ICU admission and mortality by immigrant status, ethnicity and region of birth adjusted for age, sex, socioeconomic status and comorbidities were estimated using Fine and Grey competing risk models. Results: Of 1104 patients (median [IQR] age, 63.0 [51.0–76.0] years; 56% males), 57% were immigrants and 54% were White. Immigrants were slightly younger (62 vs 65 years; p = 0.050), had fewer comorbidities (1.0 vs 1.2; p < 0.001), similar crude ICU admissions rates (33.0% vs 28.2%) and lower mortality (13.3% vs 17.6%; p < 0.001) than Canadian-born. In adjusted models compared to White immigrants, Blacks (aHR 1.39, 95% CI 1.05–1.83) and Asians (1.64, 1.15–2.34) were more likely to be admitted to ICU, but there was significant heterogeneity within ethnicity group. Asians from Eastern Asia/Pacific (2.15, 1.42–3.24) but not Southern Asia (0.97, 0.49–1.93) and Caribbean Blacks (1.39, 1.02–1.89) but not SSA Blacks (1.37, 0.86–2.18) had a higher risk of ICU admission. Blacks had a higher risk of mortality (aHR 1.56, p = 0.049). Conclusions: Data disaggregated by region of birth identified subgroups of immigrants at increased risk of COVID-19 ICU admission, providing more actionable data for health policymakers to address health inequities.

Blacks had a higher risk of mortality (aHR 1.56, p=0.049).

Conclusions: Data disaggregated by region of birth identified subgroups of immigrants at increased risk of COVID-19 ICU admission, providing more actionable data for health policymakers to address health inequities.

The COVID-19 pandemic has highlighted structural inequities for vulnerable populations. It has also shown the importance of having actionable health data available so that public health and health systems can respond quickly to decrease transmission and poor health outcomes. The pandemic has disproportionately affected ethnocultural communities and migrants living in high-income countries.

Ethnoracial groups including Blacks, Asians and other visible minorities have approximately a 2-fold increased risk of infection, hospitalization and mortality due to COVID-19 in the United States and the United Kingdom. [1] [2] [3] [4] [5] Data on intensive care unit (ICU) admissions and in-hospital mortality by ethnicity are mixed. 1, 2 Migrants have a higher risk of being infected by SARS-CoV-2 (although they are less likely to be tested), being hospitalized, and dying from COVID-19. There are limited data on severity of illness once hospitalized. These health disparities are due to a complex interaction of socioeconomic health determinants that increase the

risk of exposure and a higher prevalence of underlying medical comorbidities, leading to more severe COVID-19 disease, all fueled by long-standing structural inequities. [6] [7] [8] Modern travel and migration patterns have led to increasingly diverse populations. Immigrants are an important subset of ethnic minorities and make up a significant proportion of the population in most high-income countries, including Canada (23%), Australia (29%), Germany (17%), the United Kingdom (14%), and the United States (14%). 9,10 Despite these disparities and known structural inequities, only half of the countries in Europe and the US systematically collect data on race, ethnicity, or country of birth. Canada, a high volume migrant-receiving country, does not routinely collect these variables in health datasets across most jurisdictions. 11 When collected, there is a lack of harmonization across countries as variables collected differ and there are no standardized definitions. 12 In a cohort of hospital patients with COVID-19, we aimed to determine the factors associated with ICU admission and in-hospital mortality and the impact of ethnicity, immigrant status and region of birth on these outcomes. Collecting more granular data beyond racial groups on immigrant status and country of birth may identify subgroups who would benefit from targeted COVID-19 public health interventions and will inform resource allocation.

We conducted a retrospective cohort study of all patients hospitalized with laboratory-confirmed, community-acquired SARS-CoV-2 infection at four tertiary care hospitals in Montreal, Quebec, Canada, during the first wave of the COVID-19 pandemic from March 1 

Sociodemographic and medical information was collected from the hospital electronic medical record and the laboratory system until August 31, 2020. A semi-structured phone survey was conducted, with the patient post-discharge, or next-of-kin for deceased patients,

with interpreters as needed. 

This study was approved by the CIUSSS West-Central Montréal, the CIUSSS de l'Est-de-l'Île-de-Montréal, the McGill University Health Center, and the Centre Hospitalier de l'Université de Montréal review ethics boards.

Between March 1, 2020, and June 30, 2020, 1104 patients with a laboratory-confirmed, community-acquired SARS-CoV-2 infection admitted to the hospital were included. The median age of patients was 63.0 years (IQR 51.0-76.0; range 19-102); 44% were female, and the median time from onset of symptoms to admission was 6 days (IQR 3-10). 

Canadian HCW. Country of birth data was recorded for 581 (93.4%) immigrants and included all global regions (Table 1 ). There was significant heterogeneity of median age, sex, Charlson comorbidity index and deprivation scores across regions of birth (Supplementary, Table S1 ). There were no significant associations between severity score or length of symptoms on admission by immigrant status or region of birth (Supplementary Figure S1 ).

A total of 1054 patients (95.5%) were classified into ethnicities, most of whom were White (55.9%) (Supplementary, Table S2 ).

Visible minorities were younger (median 56 vs 69 y; p<0.001), had lower Charlson comorbidity score (mean 0.8 vs 1.3; p<0.001), and a higher proportion were in the most deprived quintile of the MSDI (49.2 vs 38.4%; p=0.001) compared to Whites. There was significant heterogeneity between ethnic groups and within ethnic groups when stratified by region of birth. Caribbean Blacks were older (median 62 vs 46; p<0.001), had a higher Charlson comorbidity score (mean 0.9 vs 0.3; p<0.001) and were more likely to have diabetes (46.5 vs 19.0%; p<0.001) when compared to African Blacks. Among Asians, the only significant difference was that individuals from East Asia/Pacific were more likely to be female (54.7 vs 28.2%; p=0.01) compared to South Asians. There was no significant association between length of symptoms or severity score at presentation by ethnicity (Supplementary Figure S1 ).

Overall, 342 patients (31%) were admitted to ICU (Supplementary Table S3 ). Immigrants had a higher cumulative 30-day probability of being admitted to ICU (33.0 vs 28.2%, log-rank p=0.036) compared to the Canadian-born ( Figure 2 , Supplementary Table S3) .

After adjusting for age, sex, comorbidity score, diabetes, and the MDSI, there was a trend of increased ICU admission hazards among immigrants (aHR, 95% CI; 1.24, 1.00-1.53; p= 0.054) ( 

In-hospital mortality was 15.1% (n=167 Figure S2 ). Blacks had a higher adjusted risk of mortality (1.56, 1.00-2.43; p=0.049) than Whites, but there were no differences by region of birth (Table 3) .

Immigrants were over-represented among COVID-19 hospitalizations accounting for more than half of all admissions during the first wave of the COVID-19 pandemic in four hospitals in Montreal, Canada, but they only account for 32% of the population. 24 There was significant heterogeneity in population characteristics (age, sex, comorbidities and socioeconomic status) and hospital outcomes by region of birth and ethnicity. Asians were at increased risk of admission to the ICU. Immigrants from East Asia and the Pacific accounted for all this aggregate risk, while immigrants from South Asia were not at increased risk. Similarly, the Black population had an increased risk of ICU admission and in-hospital mortality. The Caribbean black population but not the Sub-Saharan black population was significantly at risk for these outcomes. These poorer outcomes among subgroups of immigrants remained after adjusting for sociodemographic and medical comorbidities, despite no difference in disease severity nor duration of symptoms at presentation.

Although we could not directly estimate this, we hypothesize that the high proportion of immigrants (57%) admitted to the hospital in our study was primarily driven by higher rates of SARS-CoV-2 due to increased exposure. Several other countries in Europe, the UK and the US have found a 2-fold higher risk of COVID-19 hospitalizations among ethnic minorities and immigrants despite being younger with fewer comorbidities compared to host populations. [1] [2] [3] [4] [25] [26] [27] [28] This is thought to be due to increased SARS-CoV-2 exposure resulting from crowded living and working circumstances, higher-risk occupations such as healthcare and transport, fewer opportunities to work from home, and poorer access to public health messaging. 7, 8, 26, 29, 30 In our study, we also found that the

immigrant population was younger, had fewer medical comorbidities and was more likely to be HCW (17% vs 10%) than the Canadian-born population. Immigrants accounted for 69% of all hospitalized HCW and were more likely to be Personal Support workers (52% vs. 32%) compared to Canadian HCW. Immigrant communities and immigrant HCW were disproportionately affected by COVID-19 in Quebec. The boroughs with the highest SARS-CoV-2 infection rates were those with the highest density of immigrants, the highest social deprivation, and the highest number of infected HCW (as of June 15, 2020). These were the same boroughs served by the four participating hospitals. 14,31 HCW were among the highest risk groups in the first wave and accounted for 25% of all COVID-19 cases, although they make up <4% of the population. 32 HCW whose mother tongue was other than English or

French and who were Personal Support were at highest risk and were almost twice as likely to contract SARS-CoV-2 compared to other HCW. 32

The overall ICU admission rate in our study was 31% and was similar to that reported in the United States during the first wave of the pandemic. 33 Although immigrants and ethnic minorities were younger and had fewer medical comorbidities, they had a trend toward a higher risk of being admitted to the ICU after adjusting for age, sex, SES and medical comorbidities. This finding was not due to increased severity of illness on admission or delayed presentation, given there was no difference in the severity index or the mean number of days of symptoms between immigrants, racial groups and the Canadian-born population. Studies from Italy, Spain and the UK also found that immigrants and ethnic minorities were at increased risk of ICU admission than host populations after adjusting for age and medical comorbidities. 25,28,34 We found significant heterogeneity in the risk of ICU admission among sub-groups of Asians The consistent finding across all studies is of increased risk of severe COVID-19 outcomes among hospitalized ethnic minorities and immigrants compared to host populations despite accounting for sociodemographic factors and clinical comorbidities is unexplained.

Further studies to understand the potential interactions between COVID-19 and underlying conditions or other factors driving these inequalities will be required to mitigate the impact of COVID-19 in these populations. The heterogeneity of immigrant and ethnic groups at increased risk for severe outcomes that varies within and between countries underscores the diversity of this population and the need to routinely collect granular data locally on country of birth with or without ethnicity to inform local policies.

The mortality rate in our study was 15%, which is lower than the 22% in-hospital mortality rate reported in Europe and the United This study presents the first Canadian data from a diverse population on a large sample of immigrants that reports on immigrant status, country of birth and ethnicity. In addition to controlling for medical comorbidities and social and material deprivation, we explored key variables that increase exposure, including health care work occupation and measured severity of illness at the time of admission to the hospital. Our study was limited by the inability to control BMI as this was not available in hospital charts. We could not explore other variables that increase SARS-CoV-2 exposure, such as household crowding, ability to isolate, or health-related behaviour. The factors mentioned above and other unmeasured confounders such as language proficiency of the patient, structural racism or access to care may have influenced our estimates. We had a large number of immigrants in our sample, yet once stratified by region of birth or ethnicity, small cells size limited the precision of some stratified analyses.

Modern travel and migration patterns have led to increasingly diverse populations. 9,10 Categorizing populations by race/ethnicity is inadequate to capture the diversity of the foreign-born population, as they have distinct cultural, behavioural, language, social, or environmental characteristics and legal entitlement to health care that are critical to health outcomes and are not captured in single

racial categories. In addition, a growing number of people identify as multiracial/multicultural. 11,38 Data from our study and other studies highlights the disproportionate impact of COVID-19 on foreign-born populations, the enormous heterogeneity of COVID-19 related outcomes within ethnic groups and across countries, and the significant gaps in understanding of the individual impact of social determinants, and the interaction between them. Tackling ethnic health inequalities is complex; however, collecting granular data on country of birth in addition to ethnicity is an urgent critical gap that needs to be addressed. This will more precisely identify groups who have the highest health inequities, providing more actionable health data to inform health policy and resource allocation. 

Dr. Azoulay reports personal fees from Janssen and Pfizer, outside the submitted work. (1), Black + South Asian (1). 2 Does not include diabetes. 3 Does not include 9 (0.8%) patients who were HIV positive. 

Disparities in COVID-19 Outcomes by Race, Ethnicity, and Socioeconomic Status: A Systematic-Review and Meta-analysis

Ethnic minority status as social determinant for COVID-19 infection, hospitalisation, severity, ICU admission and deaths in the early phase of the pandemic: a meta-analysis

Racial disparities in COVID-19 pandemic cases, hospitalisations, and deaths: A systematic review and meta-analysis

Racial and Ethnic Disparities in COVID-19-Related Infections, Hospitalizations, and Deaths : A Systematic Review

Individual and social determinants of SARS-CoV-2 testing and positivity in Ontario, Canada: a population-wide study

COVID-19: Exposing and addressing health disparities among ethnic minorities and migrants

European Centre for Disease Prevention and Control. Reducing COVID-19 transmission and strengthening vaccine uptake among migrant populations in the EU/EEA -3

Fine and Gray competing risk model, calendar month as strata, and in-hospital mortality as competing risk. 1 Does not include diabetes

Fine and Gray competing risk model, calendar month as strata, and in-hospital mortality as competing risk. 1 Does not include diabetes

Dr. Azoulay holds a Chercheur-Boursier Senior Award from the Fonds de Recherche du Québec -Santé and is the recipient of a William Dawson Scholar award from McGill University. We would like to acknowledge the many medical students and fellows including Pouria Alipour, Anthony Bartholy, Yousra Belkass, Francois Fabi, Craig McCullogh,Eve Melançon, Michelle Taillefer, Jillian Schniedman, Alex Silver, Aminata Soumana and study staff that were responsible for data curation and data validation