Risk factors for avoidable hospitalizations in Canada using national linked data: A retrospective cohort study

PLOS ONE RESEARCH ARTICLE Risk factors for avoidable hospitalizations in Canada using national linked data: A retrospective cohort study Lauren E. Wallar1, Laura C. Rosella ID1,2,3* 1 Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada, 2 Public Health Ontario, Toronto, Ontario, Canada, 3 Institute of Clinical Evaluative Sciences, Toronto, Ontario, Canada a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Wallar LE, Rosella LC (2020) Risk factors for avoidable hospitalizations in Canada using national linked data: A retrospective cohort study. PLoS ONE 15(3): e0229465. https://doi.org/ 10.1371/journal.pone.0229465 Editor: Juan F. Orueta, Osakidetza Basque Health Service, SPAIN Received: October 16, 2019 Accepted: February 6, 2020 Published: March 17, 2020 Copyright: © 2020 Wallar, Rosella. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The datasets used in this study belong to Statistics Canada and cannot be shared publicly because personal health information at the individual level. These data can only be accessed in secure computing environments upon approval of a project proposal and subsequent release of data for research by Statistics Canada. This prevents us from making this data available as a Supporting Information file or in a public repository. CCHS data is available through the Research Data Centres program administered by Statistics Canada (see this link for eligibility and process to request access: * Abstract Hospitalizations for certain chronic conditions are considered avoidable for adult Canadians given effective and timely primary care management. Individual-level risk factors such as income and health behaviours are not routinely collected in most hospital databases and as a result, are largely uncharacterized for avoidable hospitalization at the national level. The aim of this study was to identify and describe demographic, socioeconomic, and health behavioural risk factors for avoidable hospitalizations in Canada using linked data. A national retrospective cohort study was conducted by pooling eight cycles of the Canadian Community Health Survey (2000/2001-2011) and linking to hospitalization records in the Discharge Abstract Database (1999/2000–2012/2013). Respondents who were younger than 18 years and older than 74 years of age, residing in Quebec, or pregnant at baseline were excluded yielding a final cohort of 389,065 individuals. The primary outcome measure was time-to index avoidable hospitalization. Sex-stratified Cox proportional hazard models were constructed to determine effect sizes adjusted for various factors and their associated 95% confidence intervals. Demographics, socioeconomic status, and health behaviours are associated with risk of avoidable hospitalizations in males and females. In fully adjusted models, health behavioural variables had the largest effect sizes including heavy smoking (Male HR 2.65 (95% CI 2.17–3.23); Female HR 3.41 (2.81–4.13)) and being underweight (Male HR 1.98 (1.14–3.43); Female HR 2.78 (1.61–4.81)). Immigrant status was protective in both sexes (Male HR 0.83 (0.69–0.98); (Female HR 0.69 (0.57–0.84)). Adjustment for behavioural and clinical variables attenuated the effect of individual-level socioeconomic status. This study identified several risk factors for time-to-avoidable hospitalizations by sex, using the largest national database of linked health survey and hospitalization records. The larger effect sizes of several modifiable risk factors highlights the importance of prevention in addressing avoidable hospitalizations in Canada. Introduction Ambulatory care sensitive conditions (ACSCs) are a set of conditions for which effective and accessible preventive and primary care exists to prevent, control, or manage these conditions PLOS ONE | https://doi.org/10.1371/journal.pone.0229465 March 17, 2020 1 / 21 PLOS ONE https://www.statcan.gc.ca/eng/rdc/index). Data access needs to be approved by Statistics Canada, and output is vetted by Statistics Canada before being released. We did not receive special access to data and followed a process that is open to others. Access can be granted to others by following the request to access outlined by Statistics Canada using the link provided. Funding: This study was funded by a Canada Research Chair held by LCR (950 - 230702) Competing interests: All authors have declared that no competing interests exist. Risk factors for avoidable hospitalizations in Canada [1]. ACSC hospitalizations are considered avoidable with adequate primary care, and unnecessarily use health system resources [2]. In addition, ACSC hospitalizations are an indicator of health system performance. In the Canadian health system, hospitalizations for seven chronic ACSCs are routinely monitored, namely angina, asthma, congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), diabetes and diabetic complications, epilepsy, and hypertension [3]. Hospitalizations for chronic ACSCs may more specifically indicate insufficient disease management [4–9]. Studies have characterized risk factors for ACSC hospitalizations including demographics [10–19], rurality [5, 17, 20–26], socioeconomic status (SES) [1, 5, 15–17, 26–38], chronic morbidities [10, 16, 17, 39], and health system characteristics [5, 31, 32, 40–43], including access to care [16, 21, 34, 35, 44–50]. Access to care has been both positively [16, 35, 44–46] and negatively associated [34, 47–50] with ACSC hospitalizations, while other studies have found no significant association [21, 34]. However, studies of Canadian adult populations have found that increasing access to care is associated with increased risk of ACSC hospitalization, suggesting that factors outside of care must be examined to understand determinants of ACSC trends [6, 16, 35]. Certain individual-level risk factors such as income and health behaviours are not routinely collected at time of admission, and as a result, are largely uncharacterized in the context of ACSC hospitalizations [10, 16, 51, 52]. We aim to add to the evidence and address challenges encountered in previous studies. First, there is variability in ACSC definitions, ranging in the number and type of conditions included as well as age limits of study populations [1, 33, 53–55]. Second, previous studies that include income as a SES measure often utilize ecological information, which may incompletely capture the influence of SES on an individual’s risk of ACSC hospitalizations. Third, lack of a broader set of individual-level health characteristics precludes the ability to quantify the difference of potentially modifiable risk factors and broader social determinants as well as control for effects of healt (...truncated)