False claim shared by President Trump that only 6% of CDC-reported deaths are from COVID-19 is based on flawed reasoning
Cause of death is defined as a medical condition that triggers a chain of clinical events that leads to the death of a patient. In contrast, comorbidities are medical conditions, either pre-existing or resulting from the primary medical condition, that weaken a patient’s resistance to injuries or diseases and indirectly contribute to their death. Many patients who died from COVID-19 had comorbidities, suggesting that these conditions increased their likelihood of death from COVID-19. For these patients, COVID-19 remains their cause of death, as many would not have died from their comorbidities.
Flawed reasoning: Because 94% of COVID-19 death certificates listed comorbidities, the author of the claim incorrectly reasons that only 6% of the deaths currently attributed to COVID-19 were actually caused by the disease. It is incorrect to assume that every patient who had COVID-19 in addition to other medical conditions died from the medical conditions and not from COVID-19.
Misleading: Comorbidities are medical conditions that weaken the patient and may lower their chance of surviving COVID-19 but are not the underlying cause of death. The claim fails to consider that doctors assess the entire chain of clinical events leading to the death of a patient in order to determine the cause. For deaths to be attributed to COVID-19, the clinical events assessed must be compatible with known COVID-19 symptoms.
In late August 2020, the claim began circulating on social media that only 6% of the deaths listed as resulting from COVID-19 in the U.S. were actually caused by the disease. This inaccurate claim was also shared on Twitter by U.S. President Donald Trump. The author of the claim confuses cause of death with comorbid conditions, mistakenly or misleadingly interpreting the comorbidities listed on death certificates as the cause of death instead of COVID-19. The claim also challenges the accuracy of data reported by the U.S. Centers for Disease Control and Prevention (CDC).
The claim stems from a 26 August 2020 report by the CDC which states that 6% of the deaths from COVID-19 were not associated with comorbidities. Contrary to the claim in many Facebook posts, the CDC did not report that only 6% of the deaths are actually due to COVID-19. And the CDC didn’t “quietly update” the number of COVID-19 deaths in patients without comorbidities. As Lead Stories reported in its fact-check of the same claim, the 6% figure has been circulating since at least 12 July 2020. And even as early as 11 May 2020, the CDC reported a similar figure of 7%.
The author of the claim uses flawed reasoning to suggest that the CDC is saying that 94% of the people whose cause of death is listed as COVID-19 actually died from their comorbidities instead. An alternate version of the claim states that only 6% of the deaths currently attributed to COVID-19 are due to the disease alone, and that the comorbidities reported for the other patients with COVID-19 are additional or alternate causes of death. Both claims misrepresent comorbidity as a cause of death, instead of a factor that contributed to the patient’s demise.
In its guidelines, the CDC explains that cause of death is “the disease or injury which initiated the train of morbid events leading directly to death”. The U.S. standard certificate of death clearly indicates the immediate cause of death in Part I—which is the ultimate event that causes the death—and the underlying cause of death which is, as we explained above, the initial event that triggered the chain of events leading to death. As a result, the entire chain of events must be consistent with the known medical effects of the underlying cause of death.
By contrast, the death certificate explicitly defines comorbidities in Part II as the “other significant conditions contributing to death but not resulting in the underlying cause of death”. In other words, comorbidities are aggravating factors that decrease the overall health of the patient and weaken their ability to survive COVID-19. Hence, the major difference between a cause of death and a comorbidity is that comorbidities do not trigger the series of events leading to the patient’s death. A person dies from an underlying cause of death, but dies with comorbidities. Jeff Lancashire, the acting associate director for communications at the U.S. National Center for Health Statistics (NCHS) explained in a fact-check by PolitiFact that, “In 92% of all deaths that mention COVID-19, COVID-19 is listed as the underlying cause of death.” Therefore, it is misleading to conflate a comorbidity with the underlying cause of death by claiming that people with comorbidities did not die from COVID-19 alone.
Comorbidities are by definition not the cause of death, whether they existed before the fatal illness or arose as a consequence of a fatal illness. Therefore, the suggestion that the 94% of people listed as dying from COVID-19 who also had comorbidities listed on their death certificates actually died of a pre-existing condition relies on an incorrect definition of comorbidity. In many cases, if the disease or injury had been avoided, those patients with comorbidities (including pre-existing conditions like diabetes) would not have died at that time. For example, as shown in Table 3 of this CDC report, 4.6% of patients reported as dying from COVID-19 also had malignant neoplasms (cancer), which may have contributed to their inability to survive COVID-19.
Importantly, the CDC did not say that 94% had preexisting diseases. While some comorbidities are pre-existing, such as diabetes, others may be a consequence of the infection by SARS-CoV-2, although not directly involved in the sequence of clinical events leading to death. As Justin Lessler, an infectious disease specialist at Johns Hopkins University’s Bloomberg School of Public Health, explains in an article published by the university’s Office of Communications, some comorbidities are actually downstream of COVID-19, such as respiratory failure. In this example, the patient’s death would still be solely due to COVID-19, even though the comorbidity of respiratory failure is listed on the death certificate. In other words, the claim ignores the fact that people among the 94% have comorbidities that arose solely as a result of COVID-19 and were not pre-existing conditions. Therefore the cause of death remains the same—COVID-19.
On 16 April 2020, the World Health Organization stated that comorbidities can increase a patient’s risk of dying from COVID-19 in its international guidelines for certification and classification of COVID-19 as the cause of death:
“There is increasing evidence that people with existing chronic conditions or compromised immune systems due to disability are at higher risk of death due to COVID-19. Chronic conditions may be non-communicable diseases such as coronary artery disease, chronic obstructive pulmonary disease (COPD), and diabetes or disabilities. If the decedent had existing chronic conditions, such as these, they should be reported in Part 2 of the medical certificate of cause of death.”
In addition, the claim fails to consider that a patient’s death certificate reports the whole chain of medical events leading to their death. For instance, a typical death certificate of someone who died from COVID-19 reports that the death occurred following an acute respiratory distress syndrome due to pneumonia triggered by COVID-19. Deaths are not classified as “COVID-19 deaths” merely because the disease is confirmed or suspected. Instead, the clinical evolution of the patient has to be compatible with the course of the disease to be classified as a death from COVID-19. World Health Organization (WHO) guidelines also state that “Persons with COVID-19 may die of other diseases or accidents, such cases are not deaths due to COVID-19 and should not be certified as such.” For instance, a patient whose death certificate lists cancer as a cause of death would have presented clinical signs and symptoms consistent with cancer, not with COVID-19. Such a patient would not be reported as a COVID-19 death.
Furthermore, the claim incorrectly concludes that only the 6% of patients who did not have comorbidities actually died from the disease. By doing so, the claim falsely assumes that if a comorbidity was present in patients who died from COVID-19, then the comorbidity was the cause of death, not COVID-19. There is no reason to assume that a patient suffering from Alzheimer’s disease and COVID-19, for example, would always die from the former and never from the latter, nor that all deceased patients who were both obese and suffering from COVID-19 died from obesity and not from COVID-19.
The CDC also compares the number of deaths that occurred in 2020 with the average number of deaths from the previous year to quantify “excess deaths”. As shown in the figure below, there was a slight increase in the number of excess deaths in early January 2018, corresponding to a severe influenza season (Figure 1). A significant number of excess of deaths also occurred during the second and third quarter of 2020. Between April 2020 and May 2020 alone, the number of deaths that exceeded the average number of deaths from previous years was more than 110,000. The New York Times has reported that at least 200,000 excess deaths have occurred in the U.S. between March and August 2020. This number is far larger than the 9,000 deaths of patients who did not present comorbidities. The claim’s hypothesis is thus incompatible with the higher mortality observed in the U.S. this year.
In summary, the claim confuses the actual cause of death, which is the event that triggers a chain of medical events leading to death, with comorbidity, which is a medical condition that may weaken the overall health of a patient and thus contribute to the fatal outcome of a disease. As stated by the WHO, patients in poor health are more likely to die from COVID-19 relative to patients who are generally in good health. However, the presence of additional medical conditions does not mean that these patients cannot die from COVID-19. The claim’s logic is flawed, as it assumes that the 94% of deceased patients who had COVID-19 and another medical condition did not die from COVID-19 and always died from the other conditions. The deaths recorded in 2020 show a significant number of excess deaths compared to previous years, however there is no data or mechanism to explain why there would be an increase in the number of deaths from previously-known medical conditions, such as Alzheimer’s, diabetes or obesity. The spike in excess deaths seen this year can only be attributed to the COVID-19 pandemic caused by the novel coronavirus SARS-CoV-2.
The U.S. NCHS Chief of Mortality Statistics confirmed in an AFP fact-check that several comorbidities are a direct consequence of COVID-19 and thus cannot be considered as an unrelated, independent factor.
USA Today also covered the claim and concluded that the claim is a misinterpretation of how causes of death are determined and registered.
UPDATE (7 Sep. 2020)
Updated for clarity, in order to explicitly state that not all of the 94% patients listed with comorbidities had pre existing medical conditions. Indeed, some of those comorbidities arose from COVID-19 itself.
UPDATE (3 Sep. 2020):
Added information of the difference of definition between comorbidity and underlying cause of death and a link to the standard U.S. death certificate. Added links to additional fact-checks and articles stating that some of the listed comorbidities were not pre-existing and are a consequence of COVID-19.
UPDATE (1 Sep. 2020):
Added information and a link to a fact-check by Lead Stories demonstrating that the U.S. CDC did not “quietly update” its figures to 6% at the end of August 2020 as claimed. This figure was already reported since at least 12 July 2020.
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