Excess deaths directly and indirectly attributable to COVID-19 using routinely reported mortality data, Bishkek, Kyrgyzstan, 2020: a cross-sectional study

Abstract

Objectives: Studies on excess deaths (ED) show that reported deaths from COVID-19 underestimate death. To understand mortality for improved pandemic preparedness, we estimated ED directly and indirectly attributable to COVID-19 and ED by age groups.

Design: Cross-sectional study using routinely reported individual deaths data.

Settings: The 21 health facilities in Bishkek that register all city deaths.

Participants: Residents of Bishkek who died in the city from 2015 to 2020.

Outcome measure: We report weekly and cumulative ED by age, sex and causes of death for 2020. EDs are the difference between observed and expected deaths. Expected deaths were calculated using the historical average and the upper bound of the 95% CI from 2015 to 2019. We calculated the percentage of deaths above expected using the upper bound of the 95% CI of expected deaths. COVID-19 deaths were laboratory confirmed (U07.1) or probable (U07.2 or unspecified pneumonia).

Results: Of 4660 deaths in 2020, we estimated 840-1042 ED (79-98 ED per 100 000 people). Deaths were 22% greater than expected. EDs were greater for men (28%) than for women (20%). EDs were observed in all age groups, with the highest ED (43%) among people 65-74 years of age. Hospital deaths were 45% higher than expected. During peak mortality (1 July -21 July), weekly ED was 267% above expected, and ED by disease-specific cause of death were above expected: 193% for ischaemic heart diseases, 52% for cerebrovascular diseases and 421% for lower respiratory diseases. COVID-19 was directly attributable to 69% of ED.

Conclusion: Deaths directly and indirectly associated with the COVID-19 pandemic were markedly higher than reported, especially for older populations, in hospital settings, and during peak weeks of SARS-CoV-2 transmission. These ED estimates can support efforts to prioritise support for persons at greatest risk of dying during surges.

Keywords: COVID-19; Epidemiology; PUBLIC HEALTH.

Figure 1

Deaths per week by sex, age and place of death, Bishkek, 2020 (n=4660). Figure 1 plots on the left show registered deaths overall and by sex, place of death, age group (dark solid line), the upper and lower limits (95% CI) of historical average (grey area) and per cent of excess death (shown on the right) compared with the threshold calculated based on 2015–2019 historical data (dark dashed line). *value extends above axis. ED, excess death.

Figure 2

Deaths per week by cause of death groups, Bishkek, 2020 (n=4660). Figure 2 registered deaths by causes of deaths (dark solid line), average level based on 2015–2019 historical data (grey dash line), the upper and lower limits (95% CI) of historical average (grey area). The maximum weekly excess death number and per cent above the threshold is pointed in each figure. *excess death (ED) count and per cent above expected based on upper 95%CI of historical average. ED, excess death.

Figure 3

Weekly registered COVID-19 cases, deaths and excess deaths (A) and death due to COVID-19 (B) per week, Bishkek, 2020. Until July 15, clinical cases of COVID-19 were not included in the official statistics, and on the graph—6293 cases of unspecified pneumonia are not shown in (A). Deaths from COVID-19 included laboratory confirmed (n=222) and probable (n=335) COVID-19 and excess death due to unspecified pneumonia using baseline level (n=140) (B). A dramatic increase in the number of COVID-19 cases, as well as the total number of registered deaths, excess mortality (A), mortality from COVID-19 (B), occurred in the same period, in the summer of 2020 (the first wave). The second wave of COVID-19 cases in October–December was twice lower than the first wave and was not accompanied by a large increase in mortality.