Medical Matters: How death certs track disease

One of the less pleasant but essential duties of a doctor is the writing of death certificates. These documents serve both a legal and an epidemiological purpose; accurate statistics as to the cause of death help inform plans for future healthcare.

When I worked briefly in a UK hospice, I was introduced to the term “ash cash”. This was a reference to the more detailed certification needed before a body could be released for cremation.

I cannot remember the exact fee the certifying doctor earned but it was considered useful pocket money by junior doctors, most of whom were therefore keen to complete their share of cremation certificates.

Naming diseases
Here and in Britain, death certification involves not just recording the main cause of death but is designed to encourage you to name other diseases that may have contributed to the person's demise.

This is especially important as deaths in older people usually involve a number of chronic diseases. In the US, doctors record just one cause of death, which may lead to inaccurate statistics.

Researchers from Yale University found that while the Centres for Disease Control and Prevention (CDC) attributed only 3 per cent of recent deaths to dementia, the condition contributed to 13 per cent of deaths among the population they studied.

The 41-month study looked at deaths in some 2,245 Medicare patients, two-thirds of whom were aged over 80. The majority of older people had between three and five chronic diseases.

The paper, published last year in the Journal of the American Geriatrics Society, showed that 15 diseases had contributed to 70 per cent of deaths. Heart failure was the commonest contributor, followed by dementia.

Lung diseases such as asthma and emphysema were found in 12 per cent of deaths, while cancer contributed to just under 6 per cent.

The cancer figure was also at odds with the CDC data which, using the single cause of death model, found cancer accounted for 22 per cent of deaths.

Causes of death
It's all very different from 100-200 years ago. To celebrate its 200th year of publication last year, the New England Journal of Medicine commissioned a series of special articles. One, "The Burden of Disease and the Changing Task of Medicine" looked at the changes in causes of death from 1812 to today. In 1900, infections topped the list with pneumonia, tuberculosis and gastrointestinal illnesses (mainly infection with typhoid) being the most common causes of death.

Heart disease, stroke, kidney disease came next in the table, all of which were ranked above cancer.

But puerperal fever, previously a major cause of death in obstetrics, was already under control, thanks to hand-washing and the work of Lister. And sewerage systems and safer water sources were helping to prevent the spread of infectious disease.

Today the league table is topped by heart disease and cancer, followed by stroke and some chronic lung diseases. Pneumonia has slipped well down the list, while tuberculosis has gone from the top 10 causes of death.

In statistical terms, pneumonia and influenza dropped from 202 per 100,000 people in 1900 to 16 today. Death from heart disease rose from 137 to 199 and cancer increased from 64 to 186 per 100,000 population.

Behaviour modification
One of the messages from this comparison is how the leading causes of death today are directly related to tobacco use, poor diet and a lack of physical activity.

Infection hasn’t gone away, of course, and is recognised now as a cause of some cancers, but most killer diseases are the result of behaviours we could choose to modify.

But perhaps the biggest change is how causes of death have moved from acute illnesses to chronic diseases. Yet we still operate health systems that are more suited to managing acute rather than chronic disease. For older people especially, a good GP who orchestrates the team of specialists is an invaluable investment.

mhouston@irishtimes.com
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