Chen Anqi A, Renouf Elizabeth M, Dean Charmaine B, Hu X Joan
Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada.
Department of Civil Engineering, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
BMC Public Health. 2025 Jan 14;25(1):148. doi: 10.1186/s12889-024-21031-5.
Coronavirus disease (COVID-19) quickly spread around the world after its initial identification in Wuhan, China in 2019 and became a global public health crisis. COVID-19 related hospitalizations and deaths as important disease outcomes have been investigated by many studies while less attention has been given to the relationship between these two outcomes at a public health unit level. In this study, we aim to establish the relationship of counts of deaths and hospitalizations caused by COVID-19 over time across 34 public health units in Ontario, Canada, taking demographic, geographic, socio-economic, and vaccination variables into account.
We analyzed daily data of the 34 health units in Ontario between March 1, 2020 and June 30, 2022. Associations between numbers of COVID-19 related deaths and hospitalizations were explored over three subperiods according to the availability of vaccines and the dominance of the Omicron variant in Ontario. A generalized additive model (GAM) was fit in each subperiod. Heterogeneity across public health units was formulated via a random intercept in each of the models.
Mean daily COVID-19 deaths increased quickly as daily hospitalizations increased, particularly when daily hospitalizations were less than 20. In all the subperiods, mean daily deaths of a public health unit was significantly associated with its population size and the proportion of confirmed cases in subjects over 60 years old. The proportion of fully vaccinated (2 doses of primary series) people in the 60 + age group was a significant factor after the availability of the COVID-19 vaccines. The deprivation index, a measure of poverty, had a significantly positive effect on COVID-19 mortality after the dominance of the Omicron variant in Ontario. Quantification of these effects was provided, including effects related to public health units.
The differences in COVID-19 mortality across health units decreased over time, after adjustment for other covariates. In the last subperiod when most public health protections were released and the Omicron variant dominated, the least advantaged group might suffer higher COVID-19 mortality. Interventions such as paid sick days and cleaner indoor air should be made available to counter lifting of health protections.
2019年在中国武汉首次发现冠状病毒病（COVID-19）后，它迅速在全球传播，成为一场全球公共卫生危机。许多研究调查了与COVID-19相关的住院和死亡情况，将其作为重要的疾病结局，而在公共卫生单位层面，这两个结局之间的关系却较少受到关注。在本研究中，我们旨在确定加拿大安大略省34个公共卫生单位中，COVID-19导致的死亡人数和住院人数随时间的关系，并考虑人口统计学、地理、社会经济和疫苗接种变量。
我们分析了安大略省34个卫生单位在2020年3月1日至2022年6月30日期间的每日数据。根据疫苗的可获得性以及安大略省奥密克戎变异株的主导情况，在三个子时期内探讨了与COVID-19相关的死亡人数和住院人数之间的关联。在每个子时期拟合一个广义相加模型（GAM）。通过每个模型中的随机截距来描述公共卫生单位之间的异质性。
随着每日住院人数的增加，每日COVID-19死亡人数迅速上升，尤其是当每日住院人数少于20人时。在所有子时期，一个公共卫生单位的每日平均死亡人数与其人口规模以及60岁以上确诊病例的比例显著相关。在COVID-19疫苗可用后，60岁及以上年龄组中完全接种（2剂主要系列）人群的比例是一个显著因素。贫困衡量指标剥夺指数在安大略省奥密克戎变异株占主导后，对COVID-19死亡率有显著的正向影响。提供了这些影响的量化结果，包括与公共卫生单位相关的影响。
在调整其他协变量后，各卫生单位之间COVID-19死亡率的差异随时间减小。在最后一个子时期，当大多数公共卫生保护措施解除且奥密克戎变异株占主导时，最弱势群体可能遭受更高的COVID-19死亡率。应提供诸如带薪病假和更清洁的室内空气等干预措施，以应对卫生保护措施的解除。
