Excess COVID-19 mortality among critically ill patients in Africa

As of March 25, 2021, a global total of 124 215 843 cases of COVID-19, including 2 734 374 deaths, had been reported to WHO.¹ COVID-19 is now the 12th leading cause of death worldwide, the sixth leading cause of death in high-income countries, and the 41st leading cause of death in sub-Saharan Africa.² However, the reasons why there are lower numbers of cases and deaths reported in sub-Saharan Africa are unclear. One possibility is that there are inadequate levels of testing, which could translate to unreported COVID-19 deaths (both in hospital and those that occur outside of hospital).³

A study³ in Zambia detected COVID-19 in 70 (19·2%) of 364 deceased individuals, most of these occurring outside of hospital. In their multicentre, prospective, observational cohort study of 3140 critically ill patients (60·6% male, mean age 55·6 years [SD 16·1]) enrolled from 64 hospitals in ten African countries reported in The Lancet, the African COVID-19 Critical Care Outcomes Study (ACCCOS) Investigators⁴ show that, despite having low COVID-19 mortality rates, Africa has the highest global mortality rate in patients with COVID-19 who are critically ill: 48·2% (95% CI 46·4–50·0; 1483 of 3077 patients) against a global average of 31·5% (27·5–35·5). In addition to the previously reported drivers of mortality (eg, the patient's disease severity at presentation and having comorbidities such as HIV/AIDS, diabetes, and chronic liver disease), the ACCCOS Investigators found that having HIV/AIDS (odds ratio 1·91) and delayed access to high-care units and intensive care units (2·14) were drivers of mortality.

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Their study is, to the best of our knowledge, the first multicountry report of outcomes of critically ill patients with COVID-19 in Africa. The question is which factors drive this high mortality in a continent with lower cases of COVID-19 and overall lower mortality rates? The authors provide some insights into possible causes, such as a shortage of critical care resources and underuse of those that are available. The underuse of resources is an intriguing finding and contrary to popular belief that resources are scarce. It is shocking to see that 68% of hospitals had access to dialysis but only 10% of the patients received it, as well as to see that proning was not optimised. It is important to think beyond the availability of resources and to also consider issues of functionality. It is common in low-income countries to have expensive equipment that is non-functional due to poor maintenance or lack of skilled human resources. It has been estimated that 40% of the medical equipment in many low-income countries is out of service.⁵

The ACCCOS Investigators also report high rates of 24 h physician coverage and a nurse-to-patient ratio of 1:2. Despite this fairly good physician and nurse coverage, mortality was high, possibly because of inadequate skill sets. There are only a small number of pulmonary and critical care training programmes in Africa. Only recently has critical care been added to the anaesthesia curricula in a few African countries. With the exception of Ethiopia, most pulmonary and critical care programmes are in South Africa.⁶ In Tanzania, a survey found that there were 0·04 anaesthetists per 100 000 population and 0·15 anaesthetists of any type per 100 000 population.⁷

The high COVID-19-related mortality in Africa could also be a reflection of the virulence of SARS-CoV-2 as a pathogen. Never before has the world seen a disease that causes the severity of respiratory failure like that caused by SARS-CoV-2. Viruses constantly mutate, leading to variants. Variants of SARS-CoV-2 have recently emerged, including B.1.1.7, a highly transmissible variant that was initially identified in the south of England in September, 2020; P.1, circulating in Brazil since the middle of 2020; and B.1.351, which was first detected in South Africa in late 2020.⁸ The capacity to detect variants in Africa is limited because of inadequate skill and infrastructure for genomic sequencing. The variants have been associated with increased transmissibility and could affect the effectiveness of COVID-19 vaccines. The role of SARS-CoV-2 variants in disease severity is unclear, with only a few reports of increased severity.⁹ Could variants be responsible for the severity seen in this study? This is a question which, in a continent with severe shortage of sequencing, could take a long time to answer.

This study has several strengths, including a large sample size, robust analyses, as well as having a multisite and prospective design. However, the authors also recognise some limitations, including that the study was done in tertiary hospitals. Moreover, 23 (36%) of 64 hospitals were in South Africa and Egypt, which are better resourced countries compared with some other African countries; mortality is probably higher in lower-income African countries. Missing data were overcome by imputation. The authors, however, do not report reasons why one in two patients died without receiving oxygen. Overall, this is a well done study and the team must be congratulated.

This online publication has been corrected. The corrected version first appeared at thelancet.com on June 24, 2021