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Is the UK's liver transplant matching algorithm biased against younger patients?

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Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#11

Post by icegreentea2 »

steveBK123 wrote: post #8
icegreentea2 wrote: post #7

Earlier quoted context omitted.

What does a non "one size fits all" approach for organ matching look like? What does a non-singular matching system work? Do you arbitrarily (randomly?) split up organs into different pools and let each pool match by a different algorithm?

Yes, in the US it might look like state level / hospital system level vs 1 singular national level matching system. US has its problems, but sometimes the "laboratory of ideas" that is federated system of 50 states prevents bad outcomes like this.

The challenge is maintaining the multiple independent systems when faced with pressures like "hey, if we consolidated systems, the the % of waiting list patients who die within 6 months of enrolling goes from 8% to 4%, and the % who receive a transplant go from 60% to 65%".

The UK system undoubtedly had a bad outcome, but the reasoning behind consolidation was sound, and the benefits real and ACTUALLY achieved (just not dispersed justly). Maintaining independent systems would mitigate against some of these failures, but would long-term be out performed by a responsive consolidated system (which I think is ultimately what the article is arguing for - not against algorithms, but against black-box algorithms that are not responsive or amendable to public scrutiny and feedback).

There are definitely times and places with independent implementations provide a strong benefits, but I think this is a much more borderline scenario.

And btw, the US has a unified organ matching system.

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#12

Post by RyanHamilton »

steveBK123 wrote: post #8
icegreentea2 wrote: post #7

Earlier quoted context omitted.

What does a non "one size fits all" approach for organ matching look like? What does a non-singular matching system work? Do you arbitrarily (randomly?) split up organs into different pools and let each pool match by a different algorithm?

Yes, in the US it might look like state level / hospital system level vs 1 singular national level matching system. US has its problems, but sometimes the "laboratory of ideas" that is federated system of 50 states prevents bad outcomes like this.

The lab of ideas = advantages the rich e.g. Steve Jobs. "In 2009, Steve Jobs received a liver transplant—not in northern California where he lived, but across the country in Memphis, Tennessee. Given the general complications of both travel and a transplant, Jobs’ decision may seem like an odd choice. But it was a strategic move that almost certainly got him a liver much more quickly than if Jobs had just waited for a liver to become available in California." https://arstechnica.com/science/2017/03/live-death-math-and-...

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#13

Post by toast0 »

icegreentea2 wrote: post #7
steveBK123 wrote: post #4

I think I've worked in software/data long enough to be very very suspicious of a one-size-fits-all algorithm like this. I would be very hesitant to entrust something like organ matching to a singular matching system. There are so many ways to get it wrong - bad data, bad algo design/requirements, mistakes in implementation, people understanding the system too well being able to game it, etc. Human systems have biases…

What does a non "one size fits all" approach for organ matching look like? What does a non-singular matching system work? Do you arbitrarily (randomly?) split up organs into different pools and let each pool match by a different algorithm?

So, from the article, it sounds like this current UK system for liver transplant matchibg was developed to replace the previous regional systems. It's not clear if all of those used the same process to determine matches, but it would be possible for them to have developed different processes.

It's also likely that a cross-regional system existed, that may have been ad-hoc. If you had a patient with an exceptional need, you might ask the other regions to be on the look out for an exceptional liver that works just right for your patient. That sort of thing is harder to do in a national system where livers are allocated based on scores.

Another thing that's helpful with multiple systems is it encourages reviewing and comparing results.

For a single system, reviewing results is even more important, but comparing is harder. But you might look at things like demographics of patients who died from liver disease while on the list including how long they were on the list; how long the current people have been waiting; demographics of people who recieve a transplant and how long they waited.

If there's a bias against young people, you would likely see more young people with long wait times, etc.

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#14

Post by loeg »

icegreentea2 wrote: post #3

I think the generalized take away from this article, and the position held by the authors is: "Overall, we are not necessarily against this shift to utilitarian logic, but we think it should only be adopted if it is the result of a democratic process, not just because it’s more convenient." and "Public input about specific systems, such as the one we’ve discussed, is not a replacement for broad societal consensus on…

Hm, I think the bigger issue presented is that the algorithm in question is heavily biased against younger patients -- it deviates significantly from an ideal utilitarian model.

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#15

Post by rscho »

ipnon wrote: post #5

Similarly the main calculator used in the US to calculate 10-year risk of cardiovascular incident literally cannot compute scores for people under 40.[0] There are two consequences to this. The first is that if you are under 40 you will never encounter a physician who believes you are at risk of heart attack or stroke, even though over 100,000 Americans under 40 will experience such an incident each year. The second…

> if you are under 40 you will never encounter a physician who believes you are at risk of heart attack or stroke

This is absolutely not true. Only someone knowing nothing about healthcare could come to such a conclusion.

> guidelines that act like programs, and your local doctor is the interpreter.

Such reframing is irrational. You are reframing scientific facts into an almost completely empirical context. It doesn't work like that at all.

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#17

Post by yieldcrv »

rscho wrote: post #15
ipnon wrote: post #5

Similarly the main calculator used in the US to calculate 10-year risk of cardiovascular incident literally cannot compute scores for people under 40.[0] There are two consequences to this. The first is that if you are under 40 you will never encounter a physician who believes you are at risk of heart attack or stroke, even though over 100,000 Americans under 40 will experience such an incident each year. The second…

> if you are under 40 you will never encounter a physician who believes you are at risk of heart attack or stroke This is absolutely not true. Only someone knowing nothing about healthcare could come to such a conclusion. > guidelines that act like programs, and your local doctor is the interpreter. Such reframing is irrational. You are reframing scientific facts into an almost completely empirical context. It doesn'…

Then the entire medical industry is failing at communicating that

The relatability of OP’s shared experience has us wanting to replace most medical professionals with genAI language models as soon as the regulations allow

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#18

Post by icegreentea2 »

loeg wrote: post #14
icegreentea2 wrote: post #3

I think the generalized take away from this article, and the position held by the authors is: "Overall, we are not necessarily against this shift to utilitarian logic, but we think it should only be adopted if it is the result of a democratic process, not just because it’s more convenient." and "Public input about specific systems, such as the one we’ve discussed, is not a replacement for broad societal consensus on…

Hm, I think the bigger issue presented is that the algorithm in question is heavily biased against younger patients -- it deviates significantly from an ideal utilitarian model.

Right, so there was a flawed implementation. Even if you had democratic consent to "implement a utilitarian organ matching mode", that would not prevent this failure mode.

So what is the governance and oversight framework for ensuring democratic consent from ideation to implementation to monitoring, and how does it differ from what the UK did? The article points out that there were multiple reviews of the algorithm that identified this bias all the way back in 2019. What is the process that connects that feedback with the democratic process to ensure that flawed implementations never deploy, or are adjusted quickly.

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#19

Post by zamadatix »

hombre_fatal wrote: post #9
ipnon wrote: post #5

Similarly the main calculator used in the US to calculate 10-year risk of cardiovascular incident literally cannot compute scores for people under 40.[0] There are two consequences to this. The first is that if you are under 40 you will never encounter a physician who believes you are at risk of heart attack or stroke, even though over 100,000 Americans under 40 will experience such an incident each year. The second…

Out of curiosity, how is a physician negligent if decades of exposure to hypertension/LDL/smoking/diabetes (the variables on that calculator) give you a heart attack or stroke? By the time you're put on a statin, for example, you've already had decades of exposure due to your lifestyle. Also, I don't believe the claim that physicians don't care about CVD risk in patients <40yo including high blood pressure and high c…

Flip the issue to something less polarizing and it should appear this is a very separate scenario from what GP is talking about (even if perhaps you still don't agree it should be malpractice for some reason):

1) You go in after feeling confused and have a headache after falling from a skateboard with no helmet. The ER sends you home not having checked anything or any notes to watch out for because they think you're too young to have problems from a fall (despite many young people having problems after a fall each year). At home you die because of a brain bleed.

vs.

2) You go in after feeling confused and have a headache after falling from a skateboard with no helmet. The ER runs some tests, sees the problem, and prescribes the best course of treatment given this information. Despite this you still die or have lasting effects on your brain.

Despite the doctors not fully remedying your problem in both situations only situation 1 involves negligence for a malpractice claim because the problem isn't the outcome, it's the quality of treatment not meeting the minimum levels. Flip the scenario specifics back and what GP is saying is that it isn't considered negligence to say "you're under 40, you're fine, go home" instead of "you could seriously be having a problem. We should put you on a statin and talk over the risks/symptoms of a heart attack" because the standard of care (sort of one measurement for what's a negligent treatment action) says the calculator defines the appropriate treatment and the calculator doesn't even work for those <40. What GP is not implying is doctors are negligent just because you still had a heart attack anyways.

Re: Is the UK's liver transplant matching algorithm biased against younger patients?

#20

Post by lazyasciiart »

ipnon wrote: post #5

Similarly the main calculator used in the US to calculate 10-year risk of cardiovascular incident literally cannot compute scores for people under 40.[0] There are two consequences to this. The first is that if you are under 40 you will never encounter a physician who believes you are at risk of heart attack or stroke, even though over 100,000 Americans under 40 will experience such an incident each year. The second…

I had a heart attack at 35, despite not really having other risks. A sibling who had a heart attack is the biggest risk factor, but later my sister did not qualify for a study on heart attack risk because she was only 39.

My ER notes literally say “can’t be a heart attack but that’s what it looks like, so we’ll treat it as one for now”, which is a little unnerving.

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