Risk Factors Associated With Mortality Among Residents With Coronavirus Disease 2019 (COVID-19) in Long-term Care Facilities in Ontario, Canada

Abstract

Importance: The coronavirus disease 2019 (COVID-19) pandemic has been particularly severe among individuals residing in long-term care (LTC) facilities. As of April 10, 2020, half of Canada's COVID-19 deaths had occurred in LTC facilities.

Objective: To better understand trends and risk factors associated with COVID-19 death in LTC facilities in Ontario, Canada.

Design, setting, and participants: This cohort study of 627 LTC facilities included 269 total individuals who died of COVID-19 in Ontario to April 11, 2020, and 83 individuals who died of COVID-19 in Ontario LTC facilities to April 7, 2020. Because population denominators were not available for LTC residents, they were approximated as the total number of LTC facility beds in Ontario (79 498), assuming complete occupancy.

Exposures: Confirmed or suspected COVID-19 outbreaks; confirmed COVID-19 infection among residents and staff, diagnosed by real-time polymerase chain reaction testing.

Main outcomes and measures: COVID-19-specific mortality incidence rate ratios (IRRs) for LTC residents were calculated with community-living Ontarians older than 69 years as the comparator group. Count-based regression methods were used to model temporal trends and to identify associations of infection risk among staff and residents with subsequent LTC resident death. Model-derived IRRs for COVID-19-specific mortality were generated through bootstrap resampling (1000 replicates) to generate median and 95% credible intervals for IRR over time.

Results: Of 627 LTC facilities, 272 (43.4%) reported COVID-19 infection in residents or staff. Of 1 731 315 total individuals older than 69 years living in Ontario during the study period, 229 (<0.1%) died; of 79 498 potential residents in LTC facilities, 83 (0.1%) died. The IRR for COVID-19-related death in LTC residents was 13.1 (95% CI, 9.9-17.3) compared with community-living adults older than 69 years. The IRR increased sharply over time and was 87.3 (95% credible interval, 6.4-769.8) by April 11, 2020. Infection among LTC staff was associated with death among residents with a 6-day lag (eg, adjusted IRR for death per infected staff member, 1.17; 95% CI, 1.11-1.26).

Conclusions and relevance: In this cohort study of COVID-19-related deaths during the pandemic in Ontario, Canada, mortality risk was concentrated in LTC residents and increased during a short period. Early identification of risk requires a focus on testing, providing personal protective equipment to staff, and restructuring the LTC workforce to prevent the movement of COVID-19 between facilities.

Figure 1.. Model-Based Estimation of Coronavirus Disease 2019 Death Risk in Ontario

The 2 curves represent modeled deaths per 1000 individuals in the long-term care (LTC) population and the community-dwelling population older than 69 years in Ontario. Shaded areas represent 95% CIs.

Figure 2.. Incidence Rate Ratios for Death in Long-term Care, by Lagged Infections Among Residents and Staff

Incidence rate ratios from Poisson regression models evaluating lagged associations between staff and residents with confirmed coronavirus disease 2019. Circles represent incidence rate ratios; vertical lines, 95% CIs. Elevated risk is seen with staff infections at all lags. Elevated risk is seen only with resident infections at a 0-day lag (ie, simultaneous with deaths).