Effect Measure

Basics: the death certificate

A couple of days ago we discussed the murky questions surrounding the death of accused anthrax attacker Dr. Bruce Ivins. At the center of stipulating the cause and manner of death were the procedures for filling out the state of Maryland’s death certificate by the medical examiner. Determining and recording the cause of death is important for many other things besides the circumstances surrounding the unexplained deaths of anthrax attackers. In the US you can’t legally dispose of a body without a properly recorded death certificate and it’s a document survivors use for all manner of other purposes, from claiming a “compassionate fare” discount from an airlines to insurance money. Compiling the information also forms the basis of many public health decisions and policies. As an epidemiologist I have used death certificates for much of my research work. Here is a brief guide to your future paperwork (you won’t have to fill it in, of course; but someone will).

Standard birth and death certificates are relatively recent in the US. When my mother was born in 1904 she was among the first to have her entry into the world recorded on a standard birth certificate. When she died last year the event was recorded on a standard death certificate which was barely older than she was. Collecting this information is a local function, so the system is highly decentralized. But it is also standardized. Keeping vital records (births, deaths, marriages, divorces, etc.) is the responsibility of the states and five territories of the United States, referred to as “registration areas.” Two cities, the District of Columbia (“Washington, DC) and New York City are also their own registration areas. While the registration areas are “independent,” they use a uniform standard for collecting core information in each category. The means for doing this are by Model State Standards and forms. If you want to see what a standard Deatch Certificate looks like you can find a .pdf here. Page 2 has brief instructions for what the entry lines mean.

One of the things you can see is that the Final and Underlying Causes of Death and Other Significant Conditions (item 32) are narrative (free text) entries. If you want to keep statistics on causes of death you have to categorize them so that “stab wound tear of subclavian artery” and “severed subclavian artery from knife wound” are counted under the same heading. Figuring this out is the job of a specialist, called a nosologist, a disease coder. The codes change with time as medical knowledge changes and so far there have been ten different major revisions to the internationally agreed upon coding, called the International Causes of Death codes. Thus since 1999 most of the world has been using the once designated ICD-10. Every time the coding changes there is an issue with the comparability with the previous version. Usually what is done is to spend a year or two coding deaths simultaneously by the old and new ICD versions so that a “cross walk” can be devised to allow comparisons, but sometimes this is pretty difficult so one can see sudden discontinuities in cause specific death rates with a change in ICDs that is due only to a change in coding. It’s a complicated world.

The desire to make comparisons between countries, states or the same state over time is also the reason for presenting mortality statistics with “age adjustment.” For example, CDC, via its Morbidity and Mortality Weekly Reports publication just released 2006 age-adjusted death rates for 2006 for males and females by race:

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Just looking at the male female comparison, males had higher age-adjusted mortality than females, 924.6 versus 657.8 per 100,000 population. These are fictitious numbers, however. When I say this I am not saying they are false or made up but rather that they are numbers that have been “age adjusted” so that both are measured along the same yardstick and a meaningful comparison can be made. The reason this is necessary is that males and females (and different race categories) have different age structures. Females live longer than males so there are more older females. But mortality rates also increase with age. If you have trouble visualizing the problem think of comparing the mortality rates in college students versus Medicare recipients. The latter are much older and have a much higher mortality rate, so unless you took account of the age difference the main thing you would be comparing would be the age difference. You don’t need death certificates to know old people die at a higher rate than young people. There are different ways to make the age adjustment but the national data in the CDC bar chart are called Direct Adjustments. Here’s the idea.

What you would like is to compare the two populations as if they had the same age structure. So you count up the number of deaths per 100,000 population for males and females at each age group in the year 2006. Then you calculate how many deaths that would have produced in some common standard population. The standard population used for this was the US census population in 2000. So you are comparing deaths in males that would have occurred in 2006 if the males in 2006 had the same age structure as the US population in 2000 and the same for females. But the age structure for each was not the age structure of the population for the year 2000 neglecting sex. So the two numbers, 924.6 versus 657.8 per 100,000 population, are “fictitious” but useful because they allow comparisons. If they were not adjusted, i.e., what we call crude rates, the difference would be much less or even reversed in direction because there are many more older females than males. The crude rates would be the “real” ones, however, i.e., the actual number of deaths per 100,000 that occurred in 2006 in each sex.

You might wonder why we don’t compare mortality at each age level for males and females separately. That would also take care of the comparison problem. It would, except we would then have many comparisons to make, one for each age range. The age adjustment provides a single composite number for the comparison, although it doesn’t tell us which age ranges are producing the difference.

There is lots more to the problem of counting up causes of death than I have discussed here. The ICD-10 code book is huge, several inches thick of fine print, and it takes training and skill to learn how to use it. Then there are all the problems in how to interpret what we see and how to compare one thing with another.

Counting things up is an essential part of epidemiology but obviously there is much more to it. But if counting were the only thing, it would be complicated enough.

Comments

  1. #1 fattylittleclot
    August 15, 2008

    Just as 10% of all children are discovered not to be the product of the listed father when both blood types are known, at least 10% of death certificates cannot be coded to ICD-10 (International Classification of Diseases – I believe), the latter due to creativity on the part of the pronouncing physician. Both circumstances produce degraded data in their respective applications.
    My personal favorite ’cause of death’ was “Inadequate Protoplasm”. There’s no amount of training that let’s you code that..!

  2. #2 revere
    August 15, 2008

    flc: In our state, a narrative cause like that would be sent back to the originating local jurisdiction. It is not permissible to say “cardiac arrest” or “respiratory arrest” either.

  3. #3 Red Crayon
    August 15, 2008

    Usually what is done is to spend a year or two coding deaths simultaneously by the old and new ICD versions so that a “cross walk” can be devised to allow comparisons

    The ICD 9/10 crosswalk in the US was produced by
    taking a random sample of deaths and coding them
    both ways.

  4. #4 revere
    August 15, 2008

    Red Crayon: Yes, of course. I said it badly. I didn’t mean that all deaths were coded both ways. Thanks for clarifying.

  5. #5 Cathie
    August 15, 2008

    For many years it was ‘known’ that Scots had twice the rate of alcohol-related deaths compared to other UK countries and Ireland.

    Those of us who are Scots and Scottish-American were discomforted by the statistic, but it also caused some problems in health care based on assumptions about alcohol consumption. Then several years back a study was conducted that showed that Scottish physicians felt duty-bound to include alcohol information in the cause of death, whereas the other UK physicians included alcohol only if it could not be avoided. The actual rate of alcohol-related illness and subsequent death were the same across groups. Of course, that study is not well known — and the assumptions are still being made.

    As a statistician and epidemiologist, I view most comparative data with great caution but cause of death data are far too valuable to dismiss. A list of ‘known data biases’ would help to reduce incorrect inferences. I don’t work in this area — does anyone know if any group is taking the lead internationally to ‘standardize’ death data by documenting/compiling ‘known data biases’? It would seem to me that WHO should have this as a priority.

  6. #6 Interrobang
    August 15, 2008

    Unless I’m vastly misapprehending the problem (which is entirely possible; I won’t underestimate my capacity for blithering idiocy), it seems as though compiling a corpus of statistical data by translating ICDs to the newest version would be possible using a database-driven software application. Are people doing this? If not, if such a thing existed, would people use it?

  7. #7 Lea
    August 15, 2008

    And … it sounds far to complicated revere.

    If I were to die tomorrow I’d want the death certificate to say, died of a “broken heart due to insensitive ignorant family members”.

  8. #8 Walabio
    August 15, 2008

    Another issue is doctors protecting their cashcow:

    Back in the 19th century, a crazy doctor named Kellogg got the insane idea that masturbation causes blindness and insanity. He decided that the best way to stop masturbation was sexual mutilation. Other doctors, especially OB/Gyns followed suite because of the money from the fees.

    Ob/Gyns eventually settled on giving women unnecessary episiotomies and c�sarian sections to women and pr�pucectomies to baby boys. I shall focus on baby boys from here on out.

    100% of mutilated baby boys experience pain, reduced sexual function, and reduced sexual sensation. These are not even counted as side effects. One condition which is is meatal stenosis which effects over half of all victims.

    We know anecdotally that someteen percent require some sort of medical intervention in the days following sexual mutilation such as stitches. We know anecdotally that a single digit number of percent of victims require emergency treatment for potentially life-threatening conditions such as infection and h�morrhage in the days following genital mutilation. We know anecdotally that about .1% of victims die within a week of the mutilation. The death-certificates do not reflect this. �Why?:

    The sexual mutilation of defenseless babies is a cashcow for the Ob/Gyns. If circumcision would be listed in the top 10 causes if infant mortality in the United States of America, parents might decide that it is better to risk blindness and insanity � which is not even true � by leaving him intact rather than risk death by mutilating him. These Obn/Gyns put lies like these on theses on the death-certificates:

    Phimosis � this is not even a proper diagnosis in infancy.

    H�morrhage � the doctors never put down the cause of h�morrhage as sexual mutilation.

    Infection � Ob/Gyns never state that the infection-site is a mutilation wound.

    Congenital heart-problems � the ob/Gyns never note that the heart, although abnormal, did not go into arrest until it reacted to the pain and stress of genital torture.

    Et al

    Sometimes doctors hide the true cause of death while filling out death-certificates.

  9. #9 caia
    August 16, 2008

    Walabio — One in a thousand circumcised baby boys dies? Surely that must be an exaggeration, at least in places with modern medical care.

    The American Academy of Family Physicians states that death is rare, and cites an estimated death rate of 1 infant in 500,000 from circumcision..

    Note that I am not arguing that neonatal circumcision is either necessary or humane. I’ve read that babies who’ve been circumcised have a greater reaction to pain six months later. But “anecdotal” statistics such as those you’ve provided do not make your argument more persuasive.

    Interrobang: If I understand correctly, (also an uncertain proposition), I’m guessing it isn’t merely that the names of causes of death change, but that medicine finds out 2 or 3 or 12 different actual causes for a previous category. Or shifts a third of a previous category’s deaths to something else. But if the medical examiner at the time didn’t have the newest information, there might not be any retrospective way to know how the older deaths should be categorized.

    I suppose you could always divide them proportionally according to how they break up now, but that would be imposing the current data on the old data, perhaps without justification.

  10. #10 Walabio
    August 16, 2008

    caia:

    > The American Academy of Family Physicians states that death is rare, and cites an estimated death rate of 1 infant in 500,000 from circumcision..

    Does not 1 in 500,000 ring alarm-bells for you? The death-rate could not be that low. It must be higher. as an example, the death-rate from tonsillectomy is officially about 1 in 15,000.

    Prpucectomies have 2 important qualities for Ob/Gyns:

    0. – They are medically unnecessary as a medically unnecessary sexual mutilation, ethically, doctors should not perform them.

    1. – They are lucrative Individually, they earn the Ob/Gyns hundreds of dollars and collectively, an Ob/Gyn can earn tens of thousands of dollars more per year.

    The Ob/Gyns have an incentive to hide deaths. If a baby dies from sepsis of the mutilation-wound 6 days after mutilation, it is in their best interest to put down the cause of death as sepsis with not mention of mutilation.

    1 in 500,000 is impossibly low. Is not it strange that genital mutilation is the safest operation ever? The very lowness in and of itself in comparison to other similar procedures should in and of itself raise red flags.

  11. #11 Bjorn Ostman
    August 17, 2008

    Walabio, could you clarify how mutilated baby boys have been mutilated, exactly? Is this just circumcision – removal of foreskin?

    Thanks.

  12. #12 Walabio
    August 17, 2008

    Bjorn Ostman:

    > “Walabio, could you clarify how mutilated baby boys have been mutilated, exactly?”

    It is what you call circumcision.

    > “Is this just circumcision – removal of foreskin?”

    There is not “just circumcision” about it. Is is mutilation:

    Mutilation:

    1. To deprive of a limb or an essential part; cripple.

    2. To disfigure by damaging irreparably: mutilate a statue.

    See synonyms at batter1.

    3. To make imperfect by excising or altering parts.

    Answers.Com

    Circumcision fits all 3 definitions; so therefore, circumcision is mutilation.

    Getting back on topic, �what is more likely?:

    * – �Sexual mutilation has a mortality-rate 30 times lower than tonsillectomy?

    * – �Ob/Gyns for protecting their cashcow, do not list genital mutilation as the cause of death; but instead however, list only the complications of pr�pucectomy such as infection and H�morrhage as the cause death on death-certificates for hiding the deaths circumcision causes?

  13. #13 Rigor
    August 17, 2008

    Well, at least circumcision protects you from penile cancer.

  14. #14 Walabio
    August 18, 2008

    Rigor | August 17, 2008 11:15 PM:

    > �Well, at least circumcision protects you from penile cancer.�

    In the sense that a body-part cannot get diseased if it is absent then cutting off over half of the skin and mucosa on the penis reduces cancer some what. By this logic, we should remove all of the teeth from all babies because dental infections are far more likely to kill than penile cancer. Given that the odds of developing penile are only 1 in 100,000

    http://cancer.org/docroot/cri/content/cri_2_4_1x_what_are_the_key_statistics_for_penile_cancer_35.asp

    Genital mutilation kills more people than penile cancer � no not even bother quoting that ridiculous statistic that mutilation is 30 times less lethal than tonsillectomy. It makes more sense to give baby boys mastectomies because men are more likely to develop mammarian cancer than penile cancer.

    From a cost-benefit point of view, it is much more costly to mutilate babies than to treat the cancer because treating the cancer only costs a few hundred thousand dollars while mutilating babies cost hundreds of dollars and one must mutilate over an hundred thousand babies to prevent 1 cancer-case. basically, it cost about an hundred times more to prevent cancer by mutilation than just to treat cancer.

    interestingly enough, all of this is now mute because now we have a vaccine against HPV which causes penile cancer which costs less than mutilation babies.