key: cord-0850135-ysjr85m7
authors: Rao, A.; Krantz, S. G.; Swanson, D. A.
title: A re-examination of the impact of COVD-19 deaths on the computation of average life expectancy
date: 2022-01-27
journal: nan
DOI: 10.1101/2022.01.20.22269578
sha: b40213473eee2ec9bab6d198abca0ce83e3d117d
doc_id: 850135
cord_uid: ysjr85m7

It is natural to question the impact of COVID-19 on life expectancy. However, a newborn during the 2020-2021 period need not experience the same level of adult mortality found in 2020-2021 because there may be zero COVID-19 related deaths when the newborn reaches adulthood. Thus, life expectancy lost due to COVID-19 cannot be found simply by incorporating excess deaths due to COVID-19 and re-doing the life table computations because: (1) we know that the COVID-19 deaths need not occur every year for the next 20-25 years; and (2) once an adult, a newborn in 2021/2022 need not experience the same mortality rate that current middle and older aged COVID-19 patients experience. Using U.S. data as an example, we estimate an average of 29.68 years of life was lost to those aged 18-64 who died from COVID-19 in the U.S., noting that 74 % of the reported deaths of 18-64 occurred among 50-64 years and 10 % below 40 years. Instead of computing life expectancy years lost due to COVID-19, we recommend computing life years lost due to COVID-19.

As of January 19 th , 2022 the total worldwide COVID-19 related deaths from the beginning of the pandemic in 2019 are around 5.55 million, and total infections are around 334 million (Ritchie et al., 2022) . We also note that there have been under-reporting and under-diagnosis of these numbers (Krantz and Rao 2020, Finelli and Swerdlow 2023) . Some researchers have measured the impact of these excess deaths on population life expectancy, while others argued that life expectancy is reduced due to COVID-19 deaths (Trias-Llimós and Bilal 2020, Andrasfay and Goldman 2021 , Castro et al., 2021 , Venkataramani, O'Brien and Tsai 2021 . In general, the approach considered in these studies is one of the commonly accepted techniques using period life tables (Chan, Cheng, and Martin 2021, Yusuf, Martins, and Swanson 2014) . However, the middle and older-aged excess deaths during 2020-21 influence the computation of life expectancy of newborn babies of 2020-21 in all of them. In essence, these studies assume that the current mortality rates among adults will have the same pattern when a current newborn reaches adulthood, and, accordingly, survival probabilities were computed. However, a newborn in 2020 need not be influenced by COVID-19 excess adult deaths during 2020-21 because these deaths may not occur every year for the next 20-30 years. Misra (1998) argued that one needs to consider the lives lost due to a cause of interest and then compute the mean life lost by all deaths.

. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted January 27, 2022. ; https://doi.org/10. 1101 /2022 In general, we agree with this approach, and extend it by proposing that each individual life lost due to COVID-19 should be associated with computing the impact of excess deaths due to COVID-19. As an example, we consider the distribution of deaths in the U.S. until November, 2021 and construct the life years lost due to COVID-19 using the person-years data and adjusting the average life years lived relative to the corresponding COVID-19 deaths. Figure 1 provides a description of the data and our idea of computing average personyears lost due to COVID-19. Computational details are found in the Appendix.

Following Goldstein and Lee (2020) and Heuveline (2021) , we next compute the loss of expected remaining life due to COVID-19.

Computation of remaining loss of life due to COVID-19 involves some level of uncertainty. However, this approach provides a better measure than simply computing the loss of years in life expectancy using a contemporary period life . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted January 27, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted January 27, 2022. ; https://doi.org/10.1101/2022.01.20.22269578 doi: medRxiv preprint 19. Our computations show, on average, that 29.68 years of these 34.5 years were lost due to COVID-19. Most of these deaths (74%) occurred in age group 50-64 while only about 10 % of these deaths occurred among people below 40 years of age.

The average remaining years that would have been there for the individuals in the U.S. who died due to COVID-19 in various age groups are as follows: 56.2 (aged 18-29); 45.9 (aged 30-39); 36.9 (aged 40-49); 25.8 (aged 50-64); 10.8 (aged 65-74); 9.6 (aged 75-84); and 4.0 (aged 85+).

In this paper, we provide an estimate of a loss of average life due to excess deaths due to COVID-19 in the U.S. that represents an improvement over the period life table-based methods that measure impact on life expectancies.

However, it has limitations that are largely unavoidable. One such limitation includes assuming that the age at death of individuals within an age group is uniformly distributed. That means the remaining lifetime probability for an individual aged 39.2 years is the same as the remaining probability for an individual aged 39.9. The other standard limitations that apply to the period life table also are assumed to hold (Arias and Xu 2020, Yusuf Martins and Swanson 2014) .

. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted January 27, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 The computation of average life lost due to COVID-19 deaths during 2020-2021 proceeds as follows: individual. Note that, Three quantities of person-years that we compute are as follows:

The total person-years lived by the individuals in

The total person-years to be lived by the individuals in

The average person-years lost due to the set ‫ܦ‬ is computed as . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted January 27, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 (4) we compute the conditional probability,

where the event of both can be approximated as . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

The copyright holder for this preprint this version posted January 27, 2022. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)

The copyright holder for this preprint this version posted January 27, 2022. ; https://doi.org/10. 1101 /2022 

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