11 October 2012

Mortality

Since I have a limited number of pictures left to post, I'll interrupt recapping my Cape Town trip to talk a bit about mortality here in South Africa.  As I had mentioned in an early post, South Africans face one of the highest death rates in the world, and consequently, have one of the lowest life expectancies of any population on the planet.  One of the requirements of my assignment here is to discuss a bit about the work I do back in the US, and so I thought it might be interesting to share a bit about the causes of death here and how they compare to the United States.

Top 10 Causes of Death, United States 2009

1 Heart Disease 25%
2 Cancer 23%
3 Respiratory Diseases 6%
4 Stroke 5%
5 Accidents 5%
6 Alzheimer's Disease 3%
7 Diabetes 3%
8 Influenza & Pneumonia 2%
9 Kidney Disease 2%
10 Suicide 2%

Top 10 Causes of Death, South Africa 2009

1 Tuberculosis 12%
2 External Causes 9%
3 Influenza & Pneumonia 8%
4 Intestinal Diseases 5%
5 Heart Disease 5%
6 Stroke 4%
7 Diabetes 4%
8 HIV 3%
9 Hypertension 3%
10 Respiratory Diseases 3%

Both countries use the same coding system and software to classify their causes of death, but the procedures each country use to rank the causes of death vary slightly, but you can still see that the mortality profile for the two countries is quite different.  The data quality for South Africa is also a bit murky; they feel that they capture about 93% of all the deaths that occur, but the accuracy and completeness of the data that is actually reported on the certificates is suspect at times.  In some cases, the family is interviewed to determine the cause of death, and the stigma surrounding HIV may also cause it to be under-reported on the Death Certificate (a problem that may exist in the US as well).

"External Causes" refers to any causes of death that come about because of something that happens to you externally, not a natural cause of death where something has gone wrong within your body system.  These external causes range from drowning to homicide to car accidents to shark attacks to medical misadventures (surgery gone wrong).  Lightning is obviously a natural force, but it has nothing to do with your body, so it's considered an external cause of death.  This doesn't have anything to do with whether or not a death is preventable.  Cirrhosis of the liver due to alcoholism certainly comes about because of an external substance (alcohol), but the mechanism by which the person died was internal.

In the US, we divide these external causes into a few categories depending on intent:  Accident, Homicide, Suicide, War, Terrorism, etc.  The overall "external" rate of death is pretty similar between the two countries; if you added up the various categories in the US, "External Causes" would be the 3rd leading cause of death overall.

Heart Disease and Cancer are causes of death found in long-lived people, and in the United States, while both are decreasing numerically, everyone will eventually die of something, and Cancer will soon overtake as the leading cause of death (it already has in many states).

The average life expectancy for an American is now approaching 80 years, but for South Africans it remains just over 50 years.

The South African Department of Health often refers to their quadruple burden of disease, and much of the public health activities in the country aim to reduce mortality in each of these four realms:
* HIV & TB (which often occur together here)
* Maternal and Child Mortality (both rates are extremely high here)
* Non-communicable Diseases (Heart Disease, Cancer, Stroke)
* Violence & Injuries

There are a few bright spots in the recent data, showing some decreases in TB mortality and Infant Mortality, in particular, but until these become long-term trends, there is still much work to do here to get the health of the country's population back on track.