What is the CDC Up to With Causes of Death?

Okay, here we go again with potentially dodgy government numbers.  I was alerted to this by a friend and this story by our local public radio affiliate.  (MPR Story)   Basically, the Centers for Disease Control may be encouraging people to treat any death in which the patient had pneumonia as a death due to coronavirus, even if there wasn’t a positive coronavirus test.  (CDC Guidance)  Okay, this is going to get a little technical, and you may be as thoroughly confused by the CDC material at the end of this discussion as I am.  The purpose of the CDC guidance is to help people filling out death certificates “where confirmed or suspected COVID-19 infection resulted in death.”

The guidance says that “informed medical opinion” should be used in deciding what cause to attribute death to, but I don’t think most of these forms are filled out by doctors, in fact I believe it is generally done by clerks and funeral directors.  The death certificates try to distinguish between the immediate cause of death and the underlying cause of death.  A certificate has a line “a” which is the immediate cause of death or the final disease or condition that led to it.  Then there are lines “b”, “c” and “d” which are used for the underlying cause of death which are the conditions, if any, that led to the cause of death listed on “a”.   If there are multiple underlying causes, you list the one that initiated the chain of events leading to death last.  So if there were three, the initiating cause would be on “d”.  You can also indicate the time interval between the immediate and the underlying causes and the date of death.

Coronavirus disease is rarely going to be the immediate cause of death; that typically might be acute respiratory distress syndrome or acute respiratory acidosis, and pneumonia is often an underlying cause that led to those conditions.  So you would see pneumonia in the underlying cause section.  But pre-existing chronic conditions, like COPD (chronic obstructive pulmonary disease) or asthma are also recognized as contributing to the death and the guidance says they should be also be listed as underlying conditions.  Now it gets a little sketchy, because the guidance says even if there wasn’t a test with a positive result for coronavirus, and you think it might be involved, you can list it as an underlying cause and you probably would list it as “d” the initiating underlying cause of death.

Now imagine that you are the person trying to fill out these death certificates.  It is a little complicated and even if there isn’t a positive test, if pneumonia is involved, you are very likely in the circumstances to attribute the death to coronavirus.  That is clearly what was happening in Italy, and I would guess it is here as well.  Meanwhile, there are still people getting influenza, which has a similar sequelae of events and immediate causes of death as coronavirus, and people very often don’t get tested for influenza.  It does make you wonder how many cases are being mis-coded.  And as we will see in a minute, the CDC doesn’t tell us how many of the deaths attributed to coronavirus had a positive test and how many were just presumed to be coronavirus under “medical judgment”, which is an odd thing to attribute to a clerk or a funeral director.

But my bigger concern is the whole interplay of underlying causes and chronic conditions.  We know from the analyses of death that have been done that serious chronic conditions, often multiple chronic conditions, are a feature of the patients who are dying.  Why is coronavirus the initiating, i.e. line d, underlying cause, when the person would very likely not have had a serious coronavirus infection if it were not for those chronic conditions?  Look at scenario A on the guidance.  This person had both COPD and hypertension, but neither was listed on the death certificate as CDC recommends it be filled out.  So the death is going to be attributed to coronavirus, even though it is quite likely that in the absence of COPD the person would not have died.

Here are some actual provisional death counts from CDC in regard to coronavirus, issued as of April 3, so very current.   (CDC Report)  The notes at the end indicate that the cause of death in this report is that initiating underlying cause of death from the death certificates.  So the problems noted above flow into this report.  In addition to coronavirus, pneumonia deaths are shown, but not deaths in which influenza and pneumonia occurred.  Again, this is problematic because influenza often isn’t tested for.  They say they are including pneumonia deaths because otherwise coronavirus deaths might be under-reported if there wasn’t a positive test result.  But there often isn’t a positive influenza test either, so the effect is to assume that if there wasn’t either a positive coronavirus or influenza test, the death was due to coronavirus.  This isn’t a small matter, this time of year there are a number of deaths due to pneumonia associated with influenza.  But now they are all attributed to coronavirus.  And even if coronavirus was present, many of these patients who died would have succumbed to flu, but by all means, let’s keep the death count inflated, so we can keep trying to justify the extreme economic shutdowns.

Note that total deaths in Table 1 are actually down from what would be expected this time of year, but this is likely due to late forms not being filed yet.  But the CDC could give us a completion factor, just like an actuary would for medical claims in a certain period, and they should, so we could then make a good comparison with the earlier year.  Unfortunately, they don’t give us the expected number of pneumonia deaths or the actual or expected number of influenza/pneumonia deaths, which would be very helpful, because if expected influenza or influenza/pneumonia  deaths are down, two things are probably happening.  One is that people who would otherwise get and die from pneumonia are getting coronavirus instead and the other is that deaths from influenza linked pneumonia are being attributed to coronavirus.

I can’t find comparable tables from the same time period in 2019 on the CDC website.  Maybe they are there, if someone can find them, that would be great.  One thing to note very carefully on Table 2, look at the percent of total deaths attributable to coronavirus that are for persons age 65 and older.  It is 79%.  And look at the number under 35.  That is about .8%.  So don’t buy the stories saying the coronavirus affects the young to any significant degree.

So here is what we need from CDC.  Tell us who actually fills out what percent of death certificates.  Not who signs them, but who fills out lines a through d.  Then give us summary reporting on time intervals between the immediate and underlying causes of death and the date of death.  That information can be critically important in determining if we have enough capacity of ICU beds and ventilators.  And give us information on the presence of underlying chronic conditions on the death certificates.