Health Reports
Avoidable hospitalizations among racialized groups in Canada: Results from the 2016 Canadian Census Health and Environment Cohort

Abstract

Background

Ambulatory care sensitive conditions (ACSCs) are illnesses that can be effectively treated and managed in primary care settings. Hospitalizations for ACSCs are therefore considered avoidable and may indicate poor access to quality primary care. This study examined trends in avoidable hospitalizations in Canada among racialized groups.

Data and methods

The 2016 Canadian Census Health and Environment Cohort was used to estimate annual age-standardized hospitalization rates (ASHRs) for ACSCs among people aged 10 to 74 from 2016/2017 to 2021/2022. ASHRs were disaggregated by sex and racialized group. Rate ratios (RRs) and 95% confidence intervals (CIs) were calculated to assess relative inequality. Logistic regression models were run, adjusting for age, sex, immigrant status, household income, and education.

Results

Across all study years, the odds of avoidable hospitalizations were significantly higher among males, Black people, and non-immigrants, and significantly lower among Chinese people and people in the category “other racialized groups not included elsewhere.” In 2020/2021, during the COVID-19 pandemic, RRs for Black females compared with non-racialized females decreased (2019/2020: RR=1.12, 95% CI=1.07 to 1.17; 2020/2021: RR=0.99, 95% CI=0.93 to 1.05), while they significantly increased for Black males compared with non-racialized males (2019/2020: RR=1.28, 95% CI=1.23 to 1.33; 2020/2021: RR=1.59, 95% CI=1.53 to 1.66).

Interpretation

This study reveals inequalities in avoidable hospitalizations in Canada, pronounced for the Black population compared with the non-racialized population, especially during the pandemic (2020/2021 and 2021/2022). Future studies examining the factors driving these inequalities (e.g., access to primary care, most prevalent conditions, geography) may inform targeted interventions.

Keywords

avoidable hospitalizations, ambulatory care, census, racialized groups, health equity.

Authors

Anita Brobbey, Vijata Sharma, and Maegan Mazereeuw are with the Centre for Health Data Integration at Statistics Canada.

 

What is already known on this subject?

• Ambulatory care sensitive conditions (ACSCs) are health conditions, such as asthma and diabetes, that should not require hospitalization with adequate primary care management, treatment, and interventions. Hospitalizations for ACSCs are therefore considered avoidable hospitalizations.
• ACSC hospitalizations are used as a proxy measure of adequate and accessible primary health care.
• Studies of hospitalizations among racial and ethnic groups in Canada are limited because of a lack of routinely collected identifiers in administrative health data.

What does this study add?

• This study provides annual estimates of ACSC hospitalizations disaggregated by racialized population in Canada (excluding Quebec) using the 2016 Canadian Census Health and Environmental Cohort, a microdata file that links respondents of the 2016 Census long-form questionnaire with the Canadian Vital Statistics – Death Database (2016 to 2021) and the Discharge Abstract Database (2016/2017 to 2021/2022).
• Across all study years, the odds of avoidable hospitalizations were significantly higher among males (compared with females), the Black population (compared with the non-racialized population) and non-immigrants (compared with immigrants), whereas they were significantly lower among the Chinese population (compared with the non-racialized population).
• Higher disparities in avoidable hospitalization were observed between the Black and the non-racialized populations, particularly in 2020/2021 during the COVID-19 pandemic.

Introduction

Reducing health disparities is a health sector priority in Canada.^Note 1 Racial disparities in hospitalization rates predate the COVID-19 pandemic, and the disparities may have worsened or broadened during the pandemic because of unequal access to ambulatory care.^Note 2, ^Note 3 In this paper, ambulatory care refers to medical services provided without admission to a hospital, including those offered in clinics, physician offices, community health centres, and urgent care centres. Ambulatory care sensitive conditions (ACSCs) are health conditions, such as asthma and diabetes, for which adequate management, treatment, and interventions delivered in the ambulatory care setting could potentially prevent hospitalization.^Note 4, ^Note 5, ^Note 6 For instance, one study showed that pharmacy ambulatory services reduced the number of emergency visits for acute exacerbations of asthma.^Note 7

ACSC hospitalizations, also called avoidable hospitalizations, are used as a proxy measure of adequate and accessible primary health care.^Note 8 Differences in rates of ACSC hospitalizations among populations can indicate inequalities in the quality of ambulatory care and disparities in access to the timely and effective treatment of certain conditions.^Note 9 Although racial and ethnic disparities in ACSC hospitalizations have been extensively studied and are well documented in the United States and other countries,^Note 5, ^Note 10 this issue has received little attention in Canada. Specifically, studies from the United States reported higher ACSC admissions for Black and Hispanic people compared with White people, indicating that these minority populations are less likely to access ambulatory care or may receive lower-quality ambulatory care than White people.^Note 3, ^Note 9, ^Note 11, ^Note 12, ^Note 13 Lower-quality ambulatory care may include ineffective communication between the patient or their family and the physician, delay in prevention services, and missed or delayed diagnoses.^Note 14

The evidence from these studies conducted in the United States cannot be generalized to the Canadian population because of differences in health care systems and the composition of racialized populations. For example, unlike the United States, where government health insurance is offered to individuals in a particular income, age, or disability bracket, Canada offers universal health insurance coverage (Canada Health Act, 1984, c. 6, s. 10).^Note 15 As a result, Canadian residents should have equal access to health services regardless of racialized background.

The limited ACSC research in Canada is partly because racial and ethnic identifiers are not routinely collected and compiled in national health administrative databases like the Discharge Abstract Database (DAD). Studies have examined disparities in ACSC hospitalizations between males and females in Canada. For instance, a 2010 report estimated that the age-standardized excess hospitalization rate for ACSCs in Canada was significantly higher for males (121 excess hospitalizations per 100,000) than for females (99 excess hospitalizations per 100,000).^Note 6, ^Note 16, ^Note 17, ^Note 18, ^Note 19 However, important questions remain about whether access to high-quality ambulatory care differs among racialized populations in Canada (South Asian, Chinese, Black, Filipino, Latin American, Arab, Southeast Asian, West Asian, Korean, Japanese, and others),^Note 20 despite their access to publicly funded health insurance. This is especially concerning because studies in Canada have found a higher prevalence of ACSCs, such as diabetes and cardiovascular disease, among some racialized populations (Black and South Asian) compared with non-racialized Canadians.^Note 1, ^Note 22 In addition, systemic racism has been identified as a contributing factor to unequal access to health services in Canada.^Note 23, ^Note 24, ^Note 25  

A more robust study of ACSC hospitalizations using population-based linked administrative health care data is needed to understand health inequalities among racialized populations and by sex in Canada. The Canadian Census Health and Environmental Cohorts (CanCHECs) provide a unique opportunity to examine hospitalization inequalities by linking the DAD with the census long-form questionnaire.

The overarching goal of this research is to estimate annual rates and trends (over six years) in ACSC hospitalizations disaggregated by racialized and non-racialized population in Canada using a comprehensive population-based linked dataset. The study will also explore the disparities in ACSC hospitalizations between racialized groups after adjusting for demographic and socioeconomic factors and immigrant status (recent immigrant, long-term immigrant, non-immigrant). The study objectives are to (1) estimate annual age-standardized ACSC hospitalization rates for racialized populations compared with the non-racialized population, (2) evaluate the association between racialized groups and ACSC hospitalizations by sex and immigrant status, and (3) model the relationship between ACSC hospitalizations and racialized groups while adjusting for demographic and socioeconomic factors.

Data and methods

The 2016 CanCHEC is a population-based linked dataset that combines data from respondents of the 2016 Census long-form questionnaire with administrative health data (e.g., hospitalizations, cancer, mortality) and annual mailing address postal codes.^Note 26 The CanCHEC data used for this analysis included the de-identified information from respondents of the 2016 Census long-form questionnaire^Note 27 linked to the Canadian Vital Statistics – Death Database (CVSD) (2016 to 2021) and the DAD (2016/2017 to 2021/2022).

About 25% of Canadian households completed the 2016 census long-form questionnaire, which collected detailed information such as income, level of education, occupation, visible minority status, immigrant status, and Indigenous identity.

The DAD includes administrative, clinical, and demographic information for all acute care (and some psychiatric, chronic rehabilitation, and day surgery) hospital discharges for all provinces and territories (excluding Quebec). This information is provided annually to Statistics Canada by the Canadian Institute for Health Information.^Note 28 The DAD contains approximately 3 million hospital discharges each year.

The CVSD is an administrative survey that annually collects demographic information and   the cause of death from all provincial and territorial vital statistics registries for all deaths in Canada. Death data are received from the province or territory where the death occurred. Death data for Yukon are not available as of 2017.

The CanCHEC datasets were created using Statistics Canada’s Social Data Linkage Environment (SDLE), which facilitates the creation of linked population data files using the Derived Record Depository (DRD). The DRD is a database containing only basic personal identifiers. The 2016 CanCHEC was created within the SDLE  from deterministic and probabilistic linkages between eligible census records and the DRD. The linkage rate for applicable years of the DAD to the DRD was 95.1%, while the rate for the CVSD to the DRD was 99.0%.

Population

The study population consisted of people aged 10 to 74 years who responded to the 2016 Census long-form questionnaire and was reduced by excluding deaths that occurred in the years before each year of interest (2016 to 2021). The ages of the population studied were adjusted by adding the difference between the year of interest and the 2016 Census. Respondents who identified as First Nations people, Métis, or Inuit on the Indigenous identity question were excluded, and are the subject of separate distinctions-based studies that consider Indigenous determinants of health and health care. Quebec residents were excluded, as their hospitalization data were unavailable. 

Outcomes

ACSC hospitalizations were defined as those with a “most responsible diagnosis” of diabetes, chronic obstructive pulmonary disease, asthma, angina, grand mal status and other epileptic convulsions, heart failure and pulmonary edema, or hypertension, coded according to the International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Canada.^Note 29 A dichotomous variable was created to indicate whether an individual from the study population experienced at least one ACSC hospitalization for each fiscal year of the study.

Covariates

The racialized group variable is derived from the “visible minority” concept from the census.^Note 20 The Employment Equity Act defines visible minorities as “persons, other than Aboriginal peoples, who are non-Caucasian in race or non-white in colour,” and this population consists of the following groups: South Asian, Chinese, Black, Filipino, Latin American, Arab, Southeast Asian, West Asian, Korean and Japanese. This article analyzes only the four largest racialized groups—South Asian, Chinese, Black, and Filipino—separately. Individuals from the Latin American, Arab, Southeast Asian, West Asian, Korean and Japanese population groups and those who identified as “visible minority, not included elsewhere (n.i.e)” or “multiple visible minorities” were combined into the “racialized population, n.i.e.” category because of the small population size and event counts. The non-racialized category includes individuals who were not considered as members of a visible minority group and excludes those with a positive response to the Indigenous identity question (Question 18 on the 2016 Census).

The immigrant status variable includes non-immigrant, recent immigrant, long-term immigrant, and non-permanent resident.^Note 30 This variable was derived from responses to the questions on landed immigrant status and citizenship in the census long-form questionnaire. Non-immigrants are individuals who are Canadian citizens by birth. Immigrants are individuals who are, or who have ever been, landed immigrants or permanent residents and those who are Canadian citizens by naturalization. Non-permanent residents are individuals without Canadian citizenship who are neither landed immigrants nor permanent residents. In this study, recent immigrants are individuals who first obtained landed immigrant or permanent resident status in Canada within 10 years before a given census. For the 2016 Census, recent immigrants are those who arrived from January 1, 2006, to May 10, 2016.

Household educational attainment was derived from the highest level of education completed as of Census Day variable, grouped into four categories: less than secondary graduation, secondary graduation or trades certificate, postsecondary certificate or diploma (excluding university degree), and university degree or equivalent.^Note 31 The highest level of education within a family was selected as the educational attainment for all family members in the household.

Low income was measured with the adjusted household income compared with the low-income measure threshold from the 2016 Census. Refer to the 2016 Census Dictionary for detailed definitions of Census of Population concepts, variables, and geographic terms, as well as historical information.^Note 32

Statistical methods

Age-standardized hospitalization rates (ASHRs) and 95% confidence intervals (CIs) were calculated for individuals with at least one ACSC hospitalization for each fiscal year from 2016/2017 to 2021/2022 per 100,000 population, using the 2011 standard population estimates with five-year age intervals. The ASHRs were disaggregated by sex, racialized group, and immigrant status. Census sampling weights were applied to ensure that estimates are representative of the Canadian household population, and 100 replicate weights specifically produced with Fay’s balanced repeated replication method for the 2016 CanCHEC were used to estimate appropriate standard errors and corresponding CIs. Controlled rounding was applied to prevent disclosure and residual disclosure risks of any confidential information provided to Statistics Canada either by survey respondents or through administrative data.^Note 33 Relative inequality was assessed by rate ratios (RRs) and corresponding 95% CIs. RRs were calculated by dividing the ASHR for racialized populations by the ASHR for the non-racialized population (the reference population).

A multiple logistic regression analysis was conducted to determine the association between the risk of ACSC hospitalization (dichotomous variable) and racialized populations while controlling for age, sex, immigrant status, and socioeconomic status (education and income). Statistical significance for all analyses was determined based on non-overlapping CIs.

Results

Study cohort

There were 26,530,850 people in the cohort aged 10 to 74 years (Table 1), with slightly more females (51.4%) than males (48.6%). Most of the population was non-racialized (76.1%), followed by South Asian (6.7%), racialized groups (n.i.e.) (6.1%), Chinese (5.2%), Black (3.0%), and Filipino (2.8%). Among the population, 72.5% of individuals were non-immigrants, 18.9% were long-term immigrants, 7.3% were recent immigrants, and 1.3% were non-permanent residents.



Hospitalizations for ambulatory care sensitive conditions

Across all study years, the ASHRs were significantly higher among males than females (Chart 1). ACSC hospitalizations decreased overall in 2020/2021 during the pandemic, with a significant decline of 39 avoidable hospitalizations per 100,000 males (ASHRs: 229.0 to 190.0) and 49 per 100,000 females (ASHRs: 186.8 to 137.8) from the 2019/2020 to the 2020/2021 fiscal year. 

Description of Chart 1



Data table for chart 1
Table summary
This table displays the results of Data table for chart 1 2016/2017, 2017/2018, 2018/2019, 2019/2020, 2020/2021, 2021/2022, Age-standardized hospitalization rate (per 100,000 population) and 95% confidence interval (appearing as column headers).

	2016/2017			2017/2018			2018/2019			2019/2020			2020/2021			2021/2022
	Age-standardized hospitalization rate (per 100,000 population)	95% confidence interval		Age-standardized hospitalization rate (per 100,000 population)	95% confidence interval		Age-standardized hospitalization rate (per 100,000 population)	95% confidence interval		Age-standardized hospitalization rate (per 100,000 population)	95% confidence interval		Age-standardized hospitalization rate (per 100,000 population)	95% confidence interval		Age-standardized hospitalization rate (per 100,000 population)	95% confidence interval
		lower	upper		lower	upper		lower	upper		lower	upper		lower	upper		lower	upper
Female	199.9	193.0	206.7	201.7	194.9	208.4	193.5	186.5	200.4	186.8	180.6	192.9	137.8	131.8	143.8	148.1	142.3	153.8
Male	244.7	237.2	252.1	251.9	243.3	260.5	234.3	225.9	242.7	229.0	220.8	237.2	190.0	183.2	196.8	187.3	181.2	193.3
Source: Statistics Canada, Canadian Census Health and Environment Cohort, 2016, linked to Discharge Abstract Database, 2016/2017 to 2021/2022.

Among racialized groups, the Black population had the highest ACSC hospitalization rates, followed by the South Asian population and the Filipino population, across all study years (Table 2). The Black population (275.3 hospitalizations per 100,000 in 2019/2020) had the highest ASHRs across all years, except in 2017/2018, when the non-racialized population (250.5 hospitalizations per 100,000) had the highest ASHRs.



The Chinese population had the lowest ACSC hospitalization rates across all study years, with the lowest (46.9 hospitalizations per 100,000) in 2020/2021.

Across all study years, all racialized groups, except for the Black population, had a lower risk of ACSC hospitalization compared with the non-racialized population (Chart 2), with the Chinese population consistently having the lowest RRs, implying their risk of ACSC hospitalization was the lowest overall. The highest RRs were observed for the Black population, and the ACSC hospitalization rate among the Black population was 1.3 times higher than that of the non-racialized population in 2020/2021 during the pandemic.

Description of Chart 2



Data table for chart 2
Table summary
This table displays the results of Data table for chart 2 2016/2017, 2017/2018, 2018/2019, 2019/2020, 2020/2021, 2021/2022, Age-standardized rate ratio and 95% confidence interval (appearing as column headers).

	2016/2017			2017/2018			2018/2019			2019/2020			2020/2021			2021/2022
	Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval
		lower	upper		lower	upper		lower	upper		lower	upper		lower	upper		lower	upper
Black	1.13	1.09	1.18	0.93	0.89	0.97	1.02	0.98	1.06	1.20	1.16	1.24	1.31	1.26	1.36	1.17	1.12	1.22
Racialized groups (n.i.e.)	0.55	0.53	0.58	0.53	0.52	0.56	0.51	0.49	0.54	0.50	0.48	0.53	0.53	0.49	0.56	0.49	0.46	0.52
South Asian	0.69	0.66	0.71	0.73	0.70	0.76	0.73	0.75	0.75	0.66	0.64	0.70	0.67	0.64	0.70	0.69	0.65	0.72
Chinese	0.26	0.24	0.28	0.20	0.18	0.22	0.23	0.21	0.25	0.21	0.19	0.23	0.26	0.24	0.29	0.27	0.25	0.30
Filipino	0.66	0.63	0.69	0.52	0.49	0.55	0.46	0.43	0.50	0.51	0.48	0.54	0.56	0.52	0.60	0.50	0.47	0.54
Note: n.i.e. = not included elsewhere. Source: Statistics Canada, Canadian Census Health and Environment Cohort, 2016, linked to Discharge Abstract Database, 2016/2017 to 2021/2022.

Comparing the ACSC hospitalizations for the Black population with the non-racialized population by sex revealed unequal increases and decreases in age-standardized RRs for the Black population (Chart 3). Chart 3 shows that, compared with the non-racialized population, the ACSC hospitalization RR for Black females decreased during the pandemic (from 1.12 times in 2019/2020 to 0.99 times in 2020/2021), while it significantly increased for Black males (from 1.28 times in 2019/2020 to 1.59 times in 2020/2021). This contributes to the high RR observed between the Black population and the non-racialized population, compared with other racialized groups.

Description of Chart 3



Data table for chart 3
Table summary
This table displays the results of Data table for chart 3 2016/2017, 2017/2018, 2018/2019, 2019/2020, 2020/2021, 2021/2022, Age-standardized rate ratio and 95% confidence interval (appearing as column headers).

	2016/2017			2017/2018			2018/2019			2019/2020			2020/2021			2021/2022
	Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval		Age-standardized rate ratio	95% confidence interval
		lower	upper		lower	upper		lower	upper		lower	upper		lower	upper		lower	upper
Black females	1.11	1.06	1.17	0.92	0.88	0.97	0.96	0.91	1.00	1.12	1.07	1.17	0.99	0.93	1.05	1.08	1.02	1.14
Black males	1.15	1.11	1.20	0.95	0.91	0.99	1.09	1.05	1.14	1.28	1.23	1.33	1.59	1.53	1.66	1.27	1.22	1.33
Source: Statistics Canada, Canadian Census Health and Environment Cohort, 2016, linked to Discharge Abstract Database, 2016/2017 to 2021/2022.

Further analysis among immigrants focused solely on long-term immigrants because of the smaller counts of more recent immigrants (Chart 4). Among long-term immigrants, the Chinese population consistently had the lowest avoidable hospitalization rates (45.6 per 100,000 in 2020/2021), while the Black population had the highest (283.8 per 100,000 in 2016/2017), compared with all racialized groups across the study years. Additionally, among long-term immigrants, the difference between the Black population and the non-racialized population was wide.

Description of Chart 4



Data table for chart 4
Table summary
This table displays the results of Data table for chart 4. The information is grouped by Racialized groups and Immigrant status (appearing as row headers), 2016/2017, 2017/2018, 2018/2019, 2019/2020, 2020/2021, 2021/2022 and age-standardized hospitalization rate (per 100,000 population) (appearing as column headers).

Racialized groups and Immigrant status	2016/2017	2017/2018	2018/2019	2019/2020	2020/2021	2021/2022
	age-standardized hospitalization rate (per 100,000 population)
Non-recent immigrant
South Asian	170.6	191.2	175.4	146.6	122.4	132.3
Chinese	61.2Data table for chart 4 Note †	56.6Data table for chart 4 Note †	51.3Data table for chart 4 Note †	50.3Data table for chart 4 Note †	45.6Data table for chart 4 Note †	55.1Data table for chart 4 Note †
Black	283.8Data table for chart 4 Note †	212.6	225.5	228.0Data table for chart 4 Note †	204.4Data table for chart 4 Note †	218.0Data table for chart 4 Note †
Filipino	186.0	139.3	129.8	115.7	103.5	109.7
Racialized groups (n.i.e.)	134.2	139.4	133.3	113.9	98.6	92.2
Non-racialized	149.0	157.5	159.5	148.5	115.4	118.9
Note † significantly different from the non-racialized population Return to note † referrer Notes: n.i.e. = not included elsewhere. Source: Statistics Canada, Canadian Census Health and Environment Cohort, 2016, linked to Discharge Abstract Database, 2016/2017 to 2021/2022.

Multiple logistic regression models

Multiple logistic regression models were used to analyze the association between ACSC hospitalizations and racialized groups while controlling for immigrant status, sex, age, education, and income (Table 3). The odds of ACSC hospitalization were significantly higher for males, older individuals, non-immigrants, and those with lower education and low income.



Similar to the descriptive analysis, in each fiscal year, the Black population was more likely to be hospitalized than the non-racialized population, while the Chinese population had the lowest odds of ACSC hospitalization after controlling for immigrant status, sex, age, education, and income. In addition, the South Asian population had higher odds of ACSC hospitalization than the non-racialized population in the adjusted model for the 2016/2017 to 2018/2019 fiscal years.

Discussion

Using the 2016 CanCHEC, the study presents annual rates of ACSC hospitalizations among several racialized groups in Canada and by sex. The results from the study revealed greater disparities for males than for females across all population groups. These sex differences are consistent with trends observed in previous research on hospitalization rates in Canada.^Note 16, ^Note 34 Additionally, the rate of ACSC hospitalizations decreased in 2020/2021 during the pandemic. This was expected as studies have shown that many patients avoided inpatient and outpatient care during the pandemic because of the fear of COVID-19 transmission.^Note 35

Among racialized groups, the Chinese population had the lowest ACSC hospitalization rates, and previous studies conducted in the United States, England, and New Zealand found similar results.^Note 5, ^Note 36 An explanation of their lower rates could be their relatively lower use of health care services because of a preference for other medical practices (e.g., traditional Chinese medicine) over “Western” health care.^Note 37 Results consistently showed that the Black population was at a substantially higher risk of ACSC hospitalization than other racialized groups and the non-racialized population, especially during the pandemic and among males. The results may reveal inequalities in access to care for ACSCs, specifically during the pandemic. The ACSC hospitalization rate for Black males increased in 2020/2021 during the pandemic, although the ACSC hospitalization rate for Black females decreased. Therefore, the highest inequality between the Black population and other non-racialized populations was observed in 2020/2021. Studies outside Canada have documented differences in ACSC hospitalization rates among different demographic and socioeconomic groups. Black and African American, Hispanic, and lower-income populations were found to have higher rates of ACSC hospital admissions than their counterparts. These studies found that the disparities were particularly pronounced for those with diabetes, hypertension, congestive heart failure, and asthma.^Note 11, ^Note 13, ^Note 38 Admission rates for these conditions may be of particular interest for future research and health policy. Furthermore, studies have found that these differences may be attributable to reduced access and barriers to quality primary health care (e.g., lack of cultural competency),^Note 39 cultural barriers, and challenges in adjusting to life in Canada, particularly in terms of socioeconomic factors.^Note 5, ^Note 13, ^Note 40 After potential confounding variables were controlled for, the Black population showed consistently higher odds of ACSC hospitalization, while the Chinese population showed lower odds compared with the non-racialized population across all study years. Results from the adjusted analysis also revealed higher odds of ACSC hospitalization for males, older individuals, non-immigrants, and those with low income and lower education. These findings are consistent with the unadjusted analysis and previous studies.^Note 8, ^Note 41, ^Note 42, ^Note 43, ^Note 44 Another noticeable finding from the adjusted model was that the South Asian population had higher ACSC hospitalization rates than the non-racialized population in the early study years, and this is consistent with studies demonstrating a relatively high prevalence of ACSC conditions among South Asian people.^Note 21, ^Note 22, ^Note 45 The disparity between the South Asian and the non-racialized populations was no longer significant from 2019/2020 to 2021/2022, warranting further study.

Non-immigrants had the highest ASHRs, followed by long-term immigrants and recent immigrants. This observation is consistent with previous studies showing better health among recent immigrants, followed by a decline in health over time.^Note 46 An additional observation came to light when the analysis was restricted to long-term immigrants: the Black population had significantly higher ACSC hospitalization rates compared with any other racialized population, suggesting a more rapid decline in the benefit of the healthy immigrant effect for this population.

Despite using a well-established population-based linked administrative health care dataset with a relatively large sample size, this study still has some limitations. First, the study is limited to only those who completed the census long-form questionnaire and excludes those living in collective dwellings or institutional settings. For a more representative sample, future studies will need to find a way to include a wider variety of living situations. Second, at least one hospitalization was considered; however, some individuals may have experienced multiple hospitalizations in a given year. Future studies should address multiple or repeat hospitalizations. Third, the analyses were unable to control for important factors that could affect the observed differences in hospitalization rates, including access to primary care data, informal care and self-care management records, and health behaviours (smoking, alcohol consumption, body mass index, physical activity, diet), as this information was unavailable in the datasets.^Note 19 Future research studies should attempt to collect this information. Fourth, this study excludes individuals from Quebec, Canada’s second-largest province by population. To be more representative, future research should include this region once hospitalization data become available. Finally, the observational nature of this study does not allow for causal inferences of the relationship between racialized groups and ACSC hospitalization rates.

In conclusion, this study shows the health inequalities among various population groups in Canada using a large retrospective cohort study. Specifically, results revealed substantial inequalities for the Black population (irrespective of their immigrant status) and the South Asian population (in some years of the study) compared with other racialized groups and the non-racialized population. Males, older individuals, non-immigrants, long-term immigrants, and those with lower income and lower household education have higher odds of ACSC hospitalization. These findings warrant further study to examine the main causes of ACSCs driving higher avoidable hospitalization rates among these population groups (e.g., age-specific or cause-specific analyses). Such research could enhance the understanding of differences, identify additional risk factors, and inform targeted health policies and interventions.