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A topic close to my heart. Or my corpus callosum


 

With the radiation hazards of CT scans under sudden scrutiny, readers may like to peek at the sparse data that CIHI has on their usage in Canada and other countries:

CT and MRI usage in select OECD countriesColumn two provides a pretty clear picture of a medical technology being used according to the available supply, not according to evidence-based clinical criteria. Canada is in no position to pat itself on the back for performing half as many CT scans as American physicians do, unless it’s also prepared to give itself a sharp rap on the skull for performing twice as many as English ones. Then again, maybe we’re in the Goldilocks Zone and we’ve gotten things juuust riiight. Of possible concern: we have the highest ratio of CT procedures to MRIs that the OECD knows of.


 

A topic close to my heart. Or my corpus callosum

  1. Well, well, this info certainly rips apart the many lies conservatives tell about the state of nuclear medicine in Canada. Not only does this show Canadians have access to as many or more MRI and CT scans as people in other nations–with the exception of the US where excess reigns–but it also shows our healthcare system is the most efficient in using this technology.

    • CT scans and MRIs actually aren't nuclear medicine, you're probably thinking of PET scans or bone scans.

      The data in the table can be interpreted a number of ways, one of which you present, but without other context there's no way to decide between that explanation and any of several others. Maybe the United States is the only country that can afford enough scans. Maybe Denmark is the only country that's not doing frivolous scans.

      Also important is that though we perform more CT exams per scanner than anyone else, this doesn't necessarily mean we use the machines more efficiently. If the machine's lifespan is limited by number of scans performed rather than age, then it's possible that by running it more often (and staffing it through the night, for example) the process becomes less efficient. I don't believe that's true in this case, but this data doesn't tell us much.

  2. This may go into the same category as the recent brouhaha in the States about breast scanning. Who knows whether the scans are necessary or useful in any of the reported cases, but let's use the statistics in support of whatever view we have of our health system as being good, bad or indifferent.

    "Column two provides a pretty clear picture of a medical technology being used according to the available supply, not according to evidence-based clinical criteria."

    I don't see how you reach this conclusion. All this seems to say is that there is a wide variance in the number of scans per scanner when you take a broad enough picture. Maybe all the Spanish scanners are in Toledo or somewhere and out of reach of those that would use them. Maybe the Canadian scanners are being unnecessarily used by hospitals to justify the huge capital expense they represent. Maybe these kinds of aggregations of data are pointless.

    • Column two is a per-CAPITA rate, NOT a per-scanner rate (columns three and four).

      • I don't see either how you arrive at that conclusion. Is it because country with public healthcare gets less CT scans per capita and the US gets more CTs done because they get to charge?

        • The "conclusion" is, the US is doing a medical procedure SIX TIMES as often as Denmark (and the difference isn't made up by means of the most obvious alternative). What purely clinical consideration could reasonably account for that? I specifically avoided any conclusion about why it is happening. We're all equally free to guess.

  3. This is useful and interesting data. The problem with it is that it only gives half the relevant information because it focuses on incidents of scans.

    It would be equally interesting and useful to know how many different patients are getting scans. My guess is that as a percentage of population, many more Canadians than Americans are getting scans because of universal coverage, but I just can't tell from this chart.

    • "…. many more Canadians than Americans are getting scans because of universal coverage, but I just can't tell from this chart."

      Read the first two columns, the ones titled exams per 1,000, and you will get an answer.

      • No, I think that just tells you how many exams are taken per 1000 people.

        Do the 90 per 1000 US MRI scans mean 90 individuals have had one scan each? It could mean equally that a handful of Americans who are fortunate enough to have health insurance coverage take multiple MRI scans. The data as presented doesn't tell us because it focuses on how often the machine gets used. Unless I am missing something here.

        • "My guess is that as a percentage of population, many more Canadians than Americans are getting scans because of universal coverage"

          Your comment suggests you have already made up your mind. How likely is it that Americans with health insurance each get four or five scans a year while Canadians get one scan per person?

          • Actually, Jolyon, I'm not taking any partisan position here. In fact, my views on health insurance are quite different than most – i.e. we should be looking at the French system.

            "How likely is it that Americans with health insurance each get four or five scans a year while Canadians get one scan per person?" That's exactly what I'm asking and what the data doesn't tell us. I guess they are, but I don't know.

            And when I say "guess" it is just that, a "guess" albeit one made with the knowledge that about 15% of Americans have zero health insurance and that, of those that have health coverage, most have basic bare bones employer offered private insurance where usage is very limited.

          • In Canada it is free to get a scan (well there is an opportunity cost of waiting and you pay for it through taxes, but it is free per use). In the US even if you have insurance you still have to pay for things. You have a deductible and a copay. One is a lump sum you pay for a given operation, and the other is a percentage of total costs that you pay. I posit that the fact that Americans have to pay for CT scans is precisely why they are more likely to chance it and avoid getting the same scan done twice.

            In Canada the cost of having multiple CT scans to me is just a matter of waiting. In the US it is substantial. First-off to get healthcare you have to pay premiums. For most people it is covered by their employer (this creates a lot of dislocations to having a functional market but that is another story). The cost out of pocket would be something like $4,000.

            The copay and deductible vary from operation to operation and insurer to insurer – I will look at my own insurance plan (which is considered a good one here). If I paid out of pocket, a CT scan would cost $1500-$3000 depending on where it was conducted. My insurance plan has a deductible of $350 for preferred care and $1,050 for non-preferred care (preferred care facilities are one that my insurance company approves of). The patient has to pay the deductible. Does the insurance company cover the rest then? No. For preferred care in high cost operations (the category into which a CT scan falls) I still have to pay $20 per visit. For non-preferred care, they will only pay 50% of a reasonable cost (which they have calculated somewhere).

            So, assuming a cost of $3000 (to an uninsured person) a CT scan will cost me $350 + $20/visit if I go to a preferred care facility. It will cost me $1050 (deductible) + $975 (50%*1950) = $2025 in a non-preferred care facility (why go to a non-preferred facility? Well what if I was out of state, had an accident, and there were no preferred care facilities around). Both, I will note, are a lot more costly than a round-trip bus to Toronto.

  4. Divide column two by column four and you get scanners per population. Canada ranks last with 11.8 CT scanners / million population, and second last (after only England) with 6.1 MRI scanners / million. But we sure use them intensively.

    • Separate and much more extensive data on the installed base of scanners for most OECD countries are available from CIHI. There's no need to infer. When it comes to MRIs we've progressed in recent years from the back half of the OECD to close to the median.

  5. Any financial incentives for the physician to recommend scans in any of the countries mentioned? Could explain different rates of use, to some extent.

    • I'm wondering if private insurance companies might drive the scan rate to some extent, as they have a great interest in establishing pre-conditions for exclusion or premium rating.

      • I was also thinking of fee for service.

        One time I fell from a platform and really cracked my kneecap. At the walkin clininc the Dr wanted me to go for an x-ray to see if it was fractured. So I asked him – well, what happens if it is determined through x-ray that it is fractured? – Stay off it and rest until it feels better. And what if I don't go for the x-ray? Same thing – stay off it and rest until it feels better.

        Mind you, the x-ray of my knee looked kinda cool [kidding]

        • You're probably right.

          It's also true that doctors often face pressure from patients to order tests, write prescriptions, and that sort of thing. Not everyone would be as calm about a fractured kneecap (and possibly never knowing for sure) as you were. (Also: OOOOOOOUCH!!!!!!!!!!!!!!!!!!!!!!!!!!!)

      • Not to mention the physicians' incentive derived from the likelihood of malpractice suits and the level of damage awards.

        • You'd also want to control for the general health of the population: A nation that puts more emphasis on preventative health (exercise, diet, environmental factors) may have fewer occurences of the sorts of diseases scans are used for in detection and treatment.

  6. That is a very interesting graph.

    It is easy to see how Americans spend more on health care, it is right in that graph. But is that a good thing, or a bad thing? They get triple the number of MRIs and double the number of cat scans as we do.

  7. What purely clinical consideration could reasonably account for that? I specifically avoided any conclusion about why it is happening

    Well, it's pretty simple why the US has such high rates of diagnostics use: it's primarily a commercial enterprise and it provides physicians plenty of opportunities to tell a patient to get a CT or MR. Fewer machines means physicians become more selective about what patients he recommends to have a diagnostic test done. It's really about rationing or the lack thereof….it has very little to do with clinical considerations because there really are no clinical criteria for deciding when or if to recommend a CT or MR

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