Let me tell you a tale of two amputations. When I was on my anesthesia rotation I had the unfortunate experience of meeting a man, younger than me, who had been working with a piece of heavy machinery. He got too close to the intake and his arm was caught in the blades. It had been mangled into a pulp. We had been consulted about a week after this happened because he required some pain control before his third surgery. The surgeons had been slowly chopping off pieces in an attempt to preserve some of the limb but because it had been so badly damaged he didn't really have any function in whatever remained of the lump of meat that was his arm. I heard later that they had eventually taken the whole thing off.
On a separate rotation through an infectious disease clinic I had another amputation experience. There was an older lady from up north who had severely uncontrolled diabetes and had got an infection in her big toe. The attending doctor immediately recommended an amputation of that toe. Luckily, his friend, the vascular surgeon, was just across the hall running a vascular surgery clinic and so they decided it could all be done right there in the room under local anaesthetic. Snip snip - in 30 minutes I went from seeing a patient to seeing a toeless patient.
I've seen a couple of other amputations as well but these stick out because they are pretty typical examples of how you would lose a limb. Whenever anyone thinks of an amputation they usually think of the first guy: a mechanical accident affecting someone young. From my very brief medicine career, amputations seem to be much more like the second story here. Somebody has a longstanding condition that causes him or her so much pain or so much neurologic damage that it eventually needs the Marie Antoinette treatment. Nevertheless, for some reason, people think of amputations as events that occur among young, fit people in their prime in traumatic circumstances. So, what does the average person at risk for an amputation look like in Canada?
For all of this I use data from the Discharge Abstract Database, which documents all of the patients who enter and exit hospitals in Canada. This covers the time period from 2009 to 2012 and has information on their stay length, medical condition, and location. One caveat is that because of data sharing agreements, the public use datafile does not include any hospitals in Quebec or BC. It's also difficult to draw inferences about amputations in the territories because they don't do a lot of surgery and they'll often medevac patients who need intensive care to southern facilities. In addition, because it's the public use data file I don't really know what's been amputated, just that something has been amputated.
So first some descriptives. There were at least 1,219 amputations in Canada over the 2009 to 2012 period. This is an underestimate as there is an additional category of diagnosis that I exclude because it also includes orthopaedic procedures to repair broken arms as well as arm amputations. The category is denoted "Resection/amputation/fixation of upper limb except shoulder/hand". It's likely this category is mostly broken bone repairs but it does also likely include some arm amputations, which are not counted in the 1,219. In terms of sex, males are much more likely to be the person having the amputation: over 63% of all patients getting amputations are men. In terms of the type of surgery performed, 63% of amputations were emergent or urgent whereas 36% were elective. There's a pretty even split of persons discharged home (50%) and to long-term care or rehab facilities (45%), but 4.5% died at some point during their stay.
But going back to our examples, how do the differences in those two stories relate to amputation rate? First lets examine age.
This graph shows two peaks in amputation rates by age. One peak is at the age of our first example: younger people (basically teens). The second peak is in older people (60-64 year olds). Ignore the peak in people who are 80 and older - it's an artefact from collapsing all people over that age into one category rather than evaluating 5 year tranches.
Also in line with the two stories is the cause of the amputations. There are only two broad diagnoses classes that I can observe when it comes to amputation; they are diagnoses related to musculoskeletal issues and cardiovascular/vascular issues. Amputations as a result of musculoskeletal (MSK) injuries - most likely traumatic injuries - are fairly evenly distributed across the age spectrum. Amputations because of vascular and other blood supply related conditions are really, almost exclusively an older occurrence. So MSK injuries disproportionately cause more amputations among the young, whereas even though there are a lot of older patients who have MSK injuries, they are much more likely to suffer from blood supply related conditions.
So we have an idea about average age of amputation. The likelihood of getting one increases as you get older, but there's a peak in younger persons, probably due to trauma. You can think of young amputations as something caused by labour force participation, accidents and other random events like the young man in our story. Vascular amputations though are more likely related to lifestyle factors: eating, smoking, etc. (this is a little simplistic - amputations due to frostbite would also probably qualify as vascular and aging itself is associated with these issues even in people who are fairly healthy). With this basic idea in mind, we can make some inferences about the healthiness of populations at a provincial level as well as the exposure that they have to accidents in the labour force. Where are people unhealthy and where are people getting into accidents?
With the reminder that I have no data on Quebec or BC, it seems like Nova Scotia is the place where you are most likely to get your limbs chopped off for whatever reason. This was surprising to me because all the surgeons I've ever talked to in Winnipeg have boasted about the ability of their service to cut off arms and legs because of how many amputations they see. Manitoba places a distant third after Nova Scotia and Newfoundland and Labrador. These three are followed by our prairie brethren in Saskatchewan. Ontario, New Brunswick, and Alberta all have the same approximate rate, and PEI rounds out the bottom of the group. I guess nobody loses arms in the potato fields.
The fact that two maritime provinces are tops in the amputation league table leads me to suspect that this has something to do with fishing but I don't know. Maybe that's just the stereotype I have of maritimers. If we look into the breakdown of MSK and vascular injuries though, this would also suggest that MSK related-accidents are driving amputations in Nova Scotia in particular.
If we make the assumption that MSK injuries are correlated to labour market accidents or trauma, it kind of makes sense that the top two provinces are Nova Scotia and Alberta. Nova Scotia has the fishery, but also, on a cursory glance at Wikipedia, a lot of mining and resource-sector jobs. Alberta has the tar sands. Both of these economies have a lot of hungry-for-appendages-type machinery. Here, Manitoba comes in third likely because of the farming sector.
In contrast though, Newfoundlanders seem to lose their legs to vascular disorders. If vascular injuries are correlated with lots of lifestyle choices that are bad for long-run health (smoking, eating McDonalds, no exercise) then, based on this, Newfoundland and Labrador is probably the unhealthiest place in Canada. Nova Scotia doesn't do much better on this measure though coming in a close second. Manitoba doesn't even make the top three, being beat out by Saskatchewan.
So the person who is most at risk of an amputation is a male in his 60s who is probably suffering from poor blood supply or diabetic infection to a limb because of poor lifestyle factors. He's probably from eastern Canada (at least on a population-adjusted basis), likely Newfoundland and Labrador.
With all of this in mind, why do people think of the young guy crushed in a thresher rather than the old lady with diabetes when they think about amputations? The latter seems much more typical of the amputations that occur in Canada. As a sort-of economist I'll throw out one possible reason: people value the former person's story more than the latter. They sympathize with somebody who has had to undergo a lot of trauma in a very short order. I would go so far as to suggest that some of this is even valuing a young limb more than an old limb. A young person who has a leg cut off has to go for the rest of his or her life without it, whereas an older person won't be using that leg for very much longer anyway. Charities definitely capitalize on this sentiment. It's never your granny hobbling around in a WarAmps commercial - it's always the cute kid with the prosthetic. Would you donate more if it was the other way around?
Is that right or is that ageism? I'm not sure. But I've got at least forty years to smoke and eat McDonalds before I need to make that decision.
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