Mortality during the COVID-19 pandemic: the blind spots in statistics

Abstract

Underreporting of COVID-19 associated death is common in both high-income countries and low-income and middle-income countries [LMICs].1Bilinski A Emanuel EJ COVID-19 and excess all-cause mortality in the US and 18 comparison countries.JAMA. 2020; 324: 2100-2102Crossref PubMed Scopus (118) Google Scholar Additionally, the use of case-fatality ratio alone has led to underestimation of mortality due to SARS-CoV-2 infection.2Shewade HD Parameswaran GG Mazumder A Gupta M Adjusting reported COVID-19 deaths for the prevailing routine death surveillance in india.Front Public Health. 2021; 91045Crossref PubMed Scopus (2) Google Scholar Hence, global bodies such as the US Centers for Disease Control and Prevention have adopted a calculation of excess all-cause mortality during a particular time frame to assess the gravity of the situation.3US Centers for Disease Control and PreventionExcess deaths associated with COVID-19.https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htmDate: 2021Date accessed: November 17, 2021Google ScholarJoseph A Lewnard and colleagues deserve an accolade for the strenuous effort put into their work, with a detailed analysis of data reported in The Lancet Infectious Diseases.4Lewnard JA Mahmud A Narayan T et al.All-cause mortality during the COVID-19 pandemic in Chennai, India: an observational study.Lancet Infect Dis. 2021; (published online Dec 22.)https://doi.org/10.1016/S1473-3099(21)00746-5Google Scholar In an observational study, the authors assessed the excess mortality during the COVID-19 pandemic by calculating the difference between observed and expected mortality during the period between March 24, 2020, and June 30, 2021, in Chennai, India. To estimate expected mortality, Lewnard and colleagues used regression models, with stratification by age and sex. Additionally, the authors measured changes in life expectancy and assessed how changes in all-cause mortality varied across communities with different socioeconomic contexts.During the study period, Lewnard and colleagues estimated 5·18 excess deaths per 1000 residents (95% uncertainty interval 5·11–5·25; a 41% increase compared with pre-pandemic period mortality), with a 4·75-times higher mortality during the peak of the second wave.The COVID-19 pandemic has predominantly been a logistical crisis rather than a pure medical crisis wherein morbidity and mortality result mainly from lack of timely diagnosis and treatment, rather than failure of appropriate treatment. Health-care systems across the globe were inadequately prepared to handle the crisis, especially in LMICs such as India. Lewnard and colleagues found a gross disparity between the government statistics on COVID-19 mortality versus the excess all-cause mortality they calculated on the basis of Chennai Civil Registration System (CRS) data. However, we argue that this excess all-cause mortality in Chennai not only represents the mortality attributable to COVID-19 per se, but also includes the COVID-19 deaths resulting from the logistical crisis resulting in suboptimal or absent management. A good proportion of this excess mortality could also include the excess deaths due to non-COVID-19 causes, as expected during this logistical crisis.5Santi L Golinelli D Tampieri A et al.Non-COVID-19 patients in times of pandemic: emergency department visits, hospitalizations and cause-specific mortality in Northern Italy.PLoS ONE. 2021; 16e0248995Crossref Scopus (57) Google Scholar, 6Bhaskaran K Bacon S Evans SJ et al.Factors associated with deaths due to COVID-19 versus other causes: population-based cohort analysis of UK primary care data and linked national death registrations within the OpenSAFELY platform.Lancet Reg Health Eur. 2021; 6100109PubMed Google ScholarDocumentation during the COVID-19 pandemic, when dealing with vast numbers of patients, is a daunting task. Although the Indian Government might have framed appropriate rules and regulations for testing, certifying, and so on, the implementation of such rules was extremely challenging during the pandemic. One needs to look closely at the local practice of how medical practitioners were filling death forms and certifying COVID-19 as the cause of death in the given government registry during this period. Deaths might have occurred after patients reached or registered at a health-care facility without being able to get tested or treated for COVID-19, and the patients dying even before reaching the health-care facility might have led to missed diagnoses of COVID-19 and erroneous reporting of the deaths as non-COVID-19-related. Whether the PCR testing was done in all such deaths (despite existing rules for a mandatory post-death RT-PCR test) before certification needs to be ascertained.We must also remember the shortcomings of the RT-PCR test on which we depend for diagnosing this rapidly spreading virus. Up to a third of COVID-19 infections could be missed by single conventional RT-PCR test, and even with a second test, the sensitivity is only up to 79%.7Clerici B Muscatello A Bai F et al.Sensitivity of SARS-CoV-2 detection with nasopharyngeal swabs.Front Public Health. 2021; 8593491Crossref PubMed Scopus (18) Google ScholarNotably, post-COVID-19 sequelae, such as life-threatening fungal infections and ischaemic events (stroke, myocardial infarction, and so on) due to the COVID-19-related prothrombotic state, might have also added to excess delayed mortalities. These deaths are unlikely to have been documented as due to COVID-19 in CRS data. Life-threatening thrombotic complications could be the initial presentation in a small percentage of COVID-19 cases, which could be missed by the attending health-care staff.The occurrence of so-called happy hypoxemia, well described in COVID-19, might have further delayed the seeking of medical attention in some cases, until the patient was overtly sick, further increasing the death count even with appropriate treatment. A small proportion of the population might have initially visited local practitioners from alternative systems of medicine, which again could have contributed to a missed or delayed diagnosis and treatment, ultimately adding to the increased mortality.Moreover, social issues such as reluctance to transfer older people (especially those who are staying alone with relatively poor quality of life) with respiratory symptoms to a health-care facility due to the fear or stigma associated with contracting COVID-19 might have additionally increased the mortality tally. Furthermore, lockdowns might have discouraged many people from seeking medical attention to some extent until they became overtly sick. Finally, there is an unsubstantiated perception that human and political factors might have influenced the documentation to some extent in certain countries.In conclusion, the increased deaths in the second wave might have occurred not only due to the higher R0 and virulence of the delta strain (B.1.617.2) and laxity in COVID-19-appropriate behaviour (the public feeling that the game is over), but also due to the inadequate anticipation of the health systems and the logistical obstacles this creates both for health-care facilities and individuals in need of care. Underreporting of COVID-19 associated death is common in both high-income countries and low-income and middle-income countries [LMICs].1Bilinski A Emanuel EJ COVID-19 and excess all-cause mortality in the US and 18 comparison countries.JAMA. 2020; 324: 2100-2102Crossref PubMed Scopus (118) Google Scholar Additionally, the use of case-fatality ratio alone has led to underestimation of mortality due to SARS-CoV-2 infection.2Shewade HD Parameswaran GG Mazumder A Gupta M Adjusting reported COVID-19 deaths for the prevailing routine death surveillance in india.Front Public Health. 2021; 91045Crossref PubMed Scopus (2) Google Scholar Hence, global bodies such as the US Centers for Disease Control and Prevention have adopted a calculation of excess all-cause mortality during a particular time frame to assess the gravity of the situation.3US Centers for Disease Control and PreventionExcess deaths associated with COVID-19.https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htmDate: 2021Date accessed: November 17, 2021Google Scholar Joseph A Lewnard and colleagues deserve an accolade for the strenuous effort put into their work, with a detailed analysis of data reported in The Lancet Infectious Diseases.4Lewnard JA Mahmud A Narayan T et al.All-cause mortality during the COVID-19 pandemic in Chennai, India: an observational study.Lancet Infect Dis. 2021; (published online Dec 22.)https://doi.org/10.1016/S1473-3099(21)00746-5Google Scholar In an observational study, the authors assessed the excess mortality during the COVID-19 pandemic by calculating the difference between observed and expected mortality during the period between March 24, 2020, and June 30, 2021, in Chennai, India. To estimate expected mortality, Lewnard and colleagues used regression models, with stratification by age and sex. Additionally, the authors measured changes in life expectancy and assessed how changes in all-cause mortality varied across communities with different socioeconomic contexts. During the study period, Lewnard and colleagues estimated 5·18 excess deaths per 1000 residents (95% uncertainty interval 5·11–5·25; a 41% increase compared with pre-pandemic period mortality), with a 4·75-times higher mortality during the peak of the second wave. The COVID-19 pandemic has predominantly been a logistical crisis rather than a pure medical crisis wherein morbidity and mortality result mainly from lack of timely diagnosis and treatment, rather than failure of appropriate treatment. Health-care systems across the globe were inadequately prepared to handle the crisis, especially in LMICs such as India. Lewnard and colleagues found a gross disparity between the government statistics on COVID-19 mortality versus the excess all-cause mortality they calculated on the basis of Chennai Civil Registration System (CRS) data. However, we argue that this excess all-cause mortality in Chennai not only represents the mortality attributable to COVID-19 per se, but also includes the COVID-19 deaths resulting from the logistical crisis resulting in suboptimal or absent management. A good proportion of this excess mortality could also include the excess deaths due to non-COVID-19 causes, as expected during this logistical crisis.5Santi L Golinelli D Tampieri A et al.Non-COVID-19 patients in times of pandemic: emergency department visits, hospitalizations and cause-specific mortality in Northern Italy.PLoS ONE. 2021; 16e0248995Crossref Scopus (57) Google Scholar, 6Bhaskaran K Bacon S Evans SJ et al.Factors associated with deaths due to COVID-19 versus other causes: population-based cohort analysis of UK primary care data and linked national death registrations within the OpenSAFELY platform.Lancet Reg Health Eur. 2021; 6100109PubMed Google Scholar Documentation during the COVID-19 pandemic, when dealing with vast numbers of patients, is a daunting task. Although the Indian Government might have framed appropriate rules and regulations for testing, certifying, and so on, the implementation of such rules was extremely challenging during the pandemic. One needs to look closely at the local practice of how medical practitioners were filling death forms and certifying COVID-19 as the cause of death in the given government registry during this period. Deaths might have occurred after patients reached or registered at a health-care facility without being able to get tested or treated for COVID-19, and the patients dying even before reaching the health-care facility might have led to missed diagnoses of COVID-19 and erroneous reporting of the deaths as non-COVID-19-related. Whether the PCR testing was done in all such deaths (despite existing rules for a mandatory post-death RT-PCR test) before certification needs to be ascertained. We must also remember the shortcomings of the RT-PCR test on which we depend for diagnosing this rapidly spreading virus. Up to a third of COVID-19 infections could be missed by single conventional RT-PCR test, and even with a second test, the sensitivity is only up to 79%.7Clerici B Muscatello A Bai F et al.Sensitivity of SARS-CoV-2 detection with nasopharyngeal swabs.Front Public Health. 2021; 8593491Crossref PubMed Scopus (18) Google Scholar Notably, post-COVID-19 sequelae, such as life-threatening fungal infections and ischaemic events (stroke, myocardial infarction, and so on) due to the COVID-19-related prothrombotic state, might have also added to excess delayed mortalities. These deaths are unlikely to have been documented as due to COVID-19 in CRS data. Life-threatening thrombotic complications could be the initial presentation in a small percentage of COVID-19 cases, which could be missed by the attending health-care staff. The occurrence of so-called happy hypoxemia, well described in COVID-19, might have further delayed the seeking of medical attention in some cases, until the patient was overtly sick, further increasing the death count even with appropriate treatment. A small proportion of the population might have initially visited local practitioners from alternative systems of medicine, which again could have contributed to a missed or delayed diagnosis and treatment, ultimately adding to the increased mortality. Moreover, social issues such as reluctance to transfer older people (especially those who are staying alone with relatively poor quality of life) with respiratory symptoms to a health-care facility due to the fear or stigma associated with contracting COVID-19 might have additionally increased the mortality tally. Furthermore, lockdowns might have discouraged many people from seeking medical attention to some extent until they became overtly sick. Finally, there is an unsubstantiated perception that human and political factors might have influenced the documentation to some extent in certain countries. In conclusion, the increased deaths in the second wave might have occurred not only due to the higher R0 and virulence of the delta strain (B.1.617.2) and laxity in COVID-19-appropriate behaviour (the public feeling that the game is over), but also due to the inadequate anticipation of the health systems and the logistical obstacles this creates both for health-care facilities and individuals in need of care. We declare no competing interests. All-cause mortality during the COVID-19 pandemic in Chennai, India: an observational studyMortality in Chennai increased substantially but heterogeneously during the COVID-19 pandemic, with the greatest burden concentrated in disadvantaged communities. Reported COVID-19 deaths greatly underestimated pandemic-associated mortality. Full-Text PDF Open Access