Here’s What the CDC’s COVID-19 Deaths Data Really Means
Last week the Centers for Disease Control and Prevention (CDC) released new death certificate data suggesting that other conditions were present in the majority of COVID-19 deaths that could have made the disease worse. But that hasn’t stopped people from trying to twist the data around in harmful ways.
The data in question is from a report regularly released by the CDC. It shows that, out of 161,392 death certificates that mentioned COVID-19, 94% also listed some other condition, such as a respiratory illness, coronary issues, underlying chronic health conditions, or sepsis.
In only 6% of cases was COVID-19 listed as the only cause of death, which some have taken—incorrectly—to mean that COVID-19 was only the true cause of death in those cases, and therefore, the disease is nowhere near as scary as we think it is. However, this is a severe misinterpretation of the data on COVID-19 deaths, experts say.
“Death certificates don’t just have one cause of death on them,” Amesh Adalja, M.D., senior scholar at the Johns Hopkins University Center for Health Security, tells SELF. In fact it’s standard practice to list a primary cause of death as well as a few potential contributing factors or conditions, he says.
So, for someone who died of COVID-19, a doctor might indicate that the cause of death is “pneumonia secondary to COVID-19, complicated by respiratory failure,” Dr. Adalja says. But the pneumonia and respiratory failure are directly caused by COVID-19, so it’s not inaccurate to classify this death as generally being due to COVID-19. A death certificate might also list any underlying conditions a patient had that could have exacerbated or contributed to their COVID-19-related death, Dr. Adalja explains, such as diabetes, chronic lung illness, heart disease, or cancer.
Although listing so many conditions on a death certificate might seem complicated, it’s all a completely normal part of medicine. That’s because “a death certificate is meant to identify the whole chain of events that led to death,” not just the final event, Stephen Hawes, Ph.D., chair of and professor in the department of epidemiology at the University of Washington School of Public Health, tells SELF.
And in the context of an emerging pandemic like coronavirus, listing multiple potential contributing factors is simply “a doctor doing their due diligence” to give as much information and context about a particular death as possible, Stephen Kissler, Ph.D., a postdoctoral research fellow in the department of immunology and infectious diseases at the Harvard T.H. Chan School of Public Health, tells SELF.
Of course, there are some limitations of using data gleaned from death certificates, Hawes says. Death certificates are really a type of administrative data, he explains, so “the data that goes into a death certificate is only as good as the information the person filling it out has.” If someone filling out a death certificate doesn’t have the full picture of what went on (because, maybe, the person died outside of a health care setting or was never formally diagnosed with COVID-19) or there isn’t a standardized way to code the various causes of death (as was the case early on in the pandemic), that opens up the possibility for error or for an incomplete understanding of what went on.
Even with that information, it’s hard to know exactly how much a particular condition listed on a death certificate actually exacerbated or contributed to an individual’s death, Dr. Adalja says. That’s partly why this kind of data works best when used for looking at larger groups of people to pick out patterns, not at the individual level.