COVID-19 as the underlying cause of death: disentangling facts and values.

In the ongoing pandemic, death statistics influence people's feelings and government policy. But when does COVID-19 qualify as the cause of death? As philosophers of medicine interested in conceptual clarification, we address the question by analyzing the World Health Organization's rules for the certification of death. We show that for COVID-19, WHO rules take into account both facts (causal chains) and values (the importance of prevention).

Since COVID-19 was declared a pandemic by WHO on 11th March 2020, the number of deaths due to the virus has become very salient for all of us. On an individual level, mortality statistics influence our emotional and cognitive uptake of the situation, and on a collective level they are key to epidemiological studies and models, which in turn inform and direct political and policy decisions. But when is someone’s death due to COVID-19 or, more specifically, when does COVID-19 qualify as the underlying cause of death? This is the conceptual question we tackle in this contribution, by analyzing the rules for the certification of death issued by the World Health Organization (WHO). As philosophers of medicine working on the methodology of current research and practice and interested in conceptual clarification, we believe that getting clear on this issue may promote a better understanding of what we are currently living through and ensure wiser evaluation of policies.

In many countries mortality statistics depend on the definitions and regulations issued by WHO (WHO 1979) and are supplemented by the instructions and codifications contained in the Reference Guide of the International Classification of Diseases (ICD) (WHO 2018). The death certificate should contain all conditions the doctor considers causally and etiologically relevant to the person’s death, but one single underlying cause of death must be specified. It is defined as “the disease or injury that initiated the train of morbid events leading directly to death, or the circumstances of the accident or violence which produced the fatal injury” (WHO 2018, 2.17.1). This definition underpins a mechanistic conception of causality. However, the guiding principle that should inform the selection of one single underlying cause is explicitly the possibility of prevention of deaths to the benefit of public health (WHO 2018, 2.19.2). Thus, a prudential or normative principle is used to select from among the causes pertinent to someone’s death. As Lindahl (1984) pointed out, the underlying cause should be a factor that can be intervened on. It means that the selection principle underpins a manipulative conception of causality.

This manipulative principle of selection is even more relevant in the case of the ongoing pandemic. In the guidelines for certification of COVID-19 as cause of death issued by the WHO we read that:On the one hand, when COVID-19 is not part of the causal chain that leads directly to death, it should not be indicated as the underlying cause of death. On the other hand, however, COVID-19 would be correctly considered the underlying cause of death even if accompanied by pre-existing chronic conditions or conditions capable of aggravating the clinical picture and increasing the risk of death. In the case of COVID-19, the situation is further complicated by the fact that a death caused by COVID-19 could be correctly recorded even in cases where the infection is only suspected or probable. Not only does the definition of death caused by COVID-19 admit “a probable case” of infection, but also the explicit instructions provided by WHO (2020) recommend that even in the case of mere suspicion of COVID-19, that is to say in the absence of swab or serological testing or other diagnostic imaging procedure that reliably confirms the infection, the disease must in any case be indicated as the underlying cause of death. If such a recommendation is at first glance rather surprising—the notion of “suspicion” linked to the diagnosis is in fact vague and subject to conflicting interpretations—it conforms to another pointer reported in ICD-11:Therefore epidemiological and public health reasons make it possible to indicate COVID-19 as the underlying cause of death even in the case of a mere unconfirmed suspicion, and thus to identify COVID-19 as the underlying cause of death even in the presence of other and independent lethal causal chains. Such a rule conforms to the manipulative principle of the underlying cause selection discussed above: the underlying cause must be selected with prevention and public health actions in mind.

A death due to COVID-19 is defined for surveillance purposes as a death resulting from a clinically compatible illness, in a probable or confirmed COVID-19 case, unless there is a clear alternative cause of death that cannot be related to COVID disease (e.g. trauma). There should be no period of complete recovery from COVID-19 between illness and death. A death due to COVID-19 may not be attributed to another disease (e.g. cancer) and should be counted independently of preexisting conditions that are suspected of triggering a severe course of COVID-19. COVID-19 should be recorded on the medical certificate of cause of death for ALL decedents where the disease caused, or is assumed to have caused, or contributed to death (WHO 2020, 3).

Whether a causal relationship is considered acceptable for mortality coding is founded not only on a medical assessment but also on epidemiological and public health considerations. Therefore, a medically acceptable relationship might be listed as unacceptable in the coding instructions because a later step in the sequence is more important from a public health point of view (WHO 2018, 2.18.2).

COVID-19 and HIV/AIDS present various similarities on the social and healthcare strategy levels (Hargreaves et al. 2020; Logie and Turan 2020). ICD-10 introduced a coding rule attributing to HIV all causes of death which are ill-defined or unknown, as well as cirrhosis of viral cause, unknown cause and tuberculosis, in people who are HIV positive. As in the case of COVID-19, this was supposed to reflect interests of importance for public health, rather than what is acceptable from a purely medical point of view. This resulted, however, in a far greater number of conditions being coded as HIV-related than before. More recent studies have shown that such an approach may not be optimal where the aim is to monitor other emerging causes of death, including some that may be related to HIV treatment, and suggest it is preferable to return to categorizing causes of death according to organ system or etiology/pathology (Hernando et al. 2012; Karat et al. 2017; Mocroft et al. 2004). Consequently other rule systems for death coding are now being proposed for HIV/AIDS (Kowalska et al. 2011). Here again, prevention and public health actions inform the decision about which rules for the certification of death are preferable.1 Given the similarities, the discussion about the identification of HIV/AIDS as the underlying cause of death can thus be useful to better frame how deaths due to COVID-19 should be considered.

In conclusion, a statement on a death certificate, identifying COVID-19 as the underlying cause of death, may be considered a non-purely descriptive predicate, as grounded on both factual (causal chains and the patient’s medical conditions before and at the time of death) and non-factual reasons (the importance of prevention and the epidemiological clause exception). The problem of objectively identifying the “real” cause of death is not only relevant from a conceptual point of view but has also many important practical consequences with regard to epidemiology, public health interventions and policies, health communication to the wide public, and political decisions. This is not the place to discuss these wider implications, but for the future we would like to suggest a more transparent discussion of the principles informing death statistics from healthcare authorities.