An analysis of mortality in Ontario using cremation data

Background: The impact of coronavirus disease 2019 (COVID-19) on all-cause mortality in Ontario is unknown. Cremations are performed for most deaths in Ontario and require coroner certification before the cremation can take place. Our objective was to provide timely analysis of deaths during the COVID-19 pandemic using cremation data. Methods: This study describes cremation certificate data from January 1, 2017, to May 31, 2020, in Ontario. Cremation records during 2020 were compared to historical records from 2017-2019, grouped according to age, month, and place of death and further stratified by COVID-19 involvement. A time series model was fit to quantify the deviation in cremation trends during the COVID-19 period. Results: There have been 33 834 cremations in Ontario in 2020, and 20 898 (62%) took place from March onwards. In April, which saw the peak number of COVID-19 cases, had an additional 1,830 cremations compared to historical averages over 2017-2019, representing a 32% increase (3 871 in 2020). Time series modelling of cremations in Ontario from January 2017 demonstrated that cremations in March, April, and May 2020 exceeded the predicted increase based on modelled estimates. Even without the COVID-19 deaths, the seasonal and numerical trends for 2020 are substantially different from the historical period. Interpretation: Cremations were higher in the months during the pandemic compared to previous years. These early estimates of mortality are critical for understanding the impact of COVID-19. This study has demonstrated the utility of cremation data to provide timely mortality information during a public health emergency.