[jvanderbot]

Well, to be fair, the overall risk of death did not seem to be lower for the invited group. The risk was 11.04 vs 11.03 for those with invited colonoscopy, with fairly large confidence interval on the control group.

But the risk of colon cancer did decrease, with a risk reduction of 18%.

Maybe they just didn't track long enough to tease out a bigger risk reduction in overall mortality, or maybe colon cancer is associated with other risk factors for mortality (like age).

Why someone would latch onto one result and not the other is probably just "blow the lid off" style reporting.

[hef19898]

Invited or not, if you don't show up to a colonoscopy you don't get one. Which means the study's data on invitations alone cannot be used to evaluate the effect of colonoscopies. Seems the study does provide data that allows this so, and shows clear differences in cancer rates and survival rates for those that did get colonoscopies.

Argueing about the randomization of these numbers, and the meta-statistical aspects of that, would be funny if the subject wasn't so serious. It is also the same level of discussion you get from people like JBP, meaning it at least misses the point by a mile.

[ricardobeat]

You have to look at it from the perspective of medical practice.

The hypothesis is that inviting people for a regular check up reduces mortality. If a lot of people don’t take up the offer because the procedure is too invasive, carries some risk, etc. then that is a very relevant variable to take into account. Vs, for example, fecal testing as mentioned in the article. It could have a lower precision, but if uptake is 100% instead of the ~40% for colonoscopy the outcomes could be much better.

[seanmcdirmid]

American health insurance really screws the pooch here. If you go for a colonoscopy without a previous fecal testing, it is a diagnostic procedure that is fully covered by your insurance without triggering deductible and copay. However, if you go for fecal testing first and then they find something suspicious that warrants a colonoscopy, it is no linger considered diagnostic (you have a legitimate problem now) and deductible/copays apply.

So in practice, doctors will tell you to just get the colonoscopy to save (your own) money.

[astura]

You're not really wrong, but you're using the wrong terms which is extremely confusing.

https://www.cancer.org/cancer/colon-rectal-cancer/detection-...

For asymptomatic people without abnormal stool, colon cancer tests are called "screening," never "diagnostic." "Screening" is covered without cost sharing. Colonoscopy, fecal tests, etc.

>But if you have a screening test other than colonoscopy and the result is positive (abnormal), you will need to have a colonoscopy. Some insurers consider this to be a diagnostic (not screening) colonoscopy, so you may have to pay the usual deductible and co-pay.

[seanmcdirmid]

Thanks for the clarification. I didn’t really know the difference in the terms being thrown around, just the oddness in the billing.

[gregw2]

You are complaining about the rare situation where someone gets fecal scanning first (and I agree this leads to perverse incentives)... But here's what the real racket is... American healthcare considers the colonoscopy preventative so the exam is covered... but if they see even a single polyp and decide to cut it off to get checked whether it is benign or not, that is not preventative but is diagnostic and thus is not covered and costs you $$$ in copays.

[astura]

They aren't supposed to do this - See the link I posted on a sibling comment

https://www.cancer.org/cancer/colon-rectal-cancer/detection-...

>Soon after the ACA became law, some insurance companies considered a colonoscopy to no longer be just a ‘screening’ test if a polyp was removed during the procedure. It would then be a ‘diagnostic’ test, and would therefore be subject to co-pays and deductibles. However, the US Department of Health and Human Services has clarified that removal of a polyp is an integral part of a screening colonoscopy, and therefore patients with private insurance should not have to pay out-of-pocket for it (although this does not apply to Medicare, as discussed below).

[cmurf]

That's what my provider told me too. However:

https://www.npr.org/sections/health-shots/2022/05/31/1101861...

[seanmcdirmid]

Huh. I didn’t see that in my exam. They did a biopsy on one polyp, but I wasn’t charged for it.

[hef19898]

Hope results were of the non-worrisome kind!

[dis-sys]

> then that is a very relevant variable to take into account.

but that variable has nothing to do with whether the procedure itself is effective or not.

[bstpierre]

The question in this context is whether it’s an effective public health measure to recommend the procedure to a population: specifically, does it reduce the number of deaths over a given period?

Whether it’s effective on an individual basis is a related, but different, different question.

[darkerside]

Behavioral medicine

[kgwgk]

> cannot be used to evaluate the effect of colonoscopies. Seems the study does provide data that allows this so, and shows clear differences in cancer rates and survival rates for those that did get colonoscopies.

Really?

You cannot simple compare the outcomes for the people who got an invitation AND got the procedure done with the outcomes for the people who didn’t get an invitation.

You need the compare them with the people who didn’t get an invitation BUT would have got the procedure done if they had been invited.

[thaumasiotes]

> Invited or not, if you don't show up to a colonoscopy you don't get one. Which means the study's data on invitations alone cannot be used to evaluate the effect of colonoscopies. Seems the study does provide data that allows this so, and shows clear differences in cancer rates and survival rates for those that did get colonoscopies.

This is not an oversight on the part of the study designers. It's called "intention to treat", and studies are done this way to get past the problem that, when you invite a bunch of people to get colonoscopies (or tell them to comply with any medical procedure), the people who go through with it are statistically very different, in all kinds of ways, from the people who don't. This makes the direct comparison of "received treatment" vs "didn't receive treatment" mostly meaningless.

You're here advocating for everyone to ignore the study and do a direct comparison of "received treatment" vs "didn't receive treatment".

Don't do this.

[hef19898]

I am not doing this, I'm saying the study cannot be used to say colonoscopies don't help.

[kgwgk]

It cannot be used to say that the help either, but you wrote “Seems the study does provide data that allows this so, and shows clear differences in cancer rates and survival rates for those that did get colonoscopies.”

[hef19898]

I read it that the invite doesn get you differnces, the colonoscopy itsrlf does. And if that isn't statistically a gold standard, randomization and all tgat, I don't care. What the study says, IMHO, is that invoting people doesn't do any good when people don't show up.

Which is an interesting problem, isn't it? Not inviting people might be an option, one that doesn't provide any benefits, except an number of letters not being sent. So I'd say keep the invites, because every single additional person showing up for a screening is a net win. Additional educating efforts will definetly help so, no idea how those can look like so.

[DanBC]

> because every single additional person showing up for a screening is a net win

We can't say that from this study.

Colonoscopy does appear to be one of the screenings that reduces mortality. (That's why this is such a surprising result and is getting a lot of attention). But that does not mean that colonoscopy screening is useful for people in their 40s. There's a lot of discussion about the benefits and risks of colonoscopy screening for people in their 50s. Colonoscopy, especially as it's practised in the US with heavy sedation, is not risk free.

[jtc331]

> I read it that the invite doesn get you differnces, the colonoscopy itsrlf does.

No, it doesn’t, because the two groups of people you’re comparing aren’t actually similar, and therefore any outcome difference can’t be tied to the intervention.

The difference in outcome between those two groups may merely be that the people who go through with the colonoscopy (not fun) are also willing to go through with their doctor’s recommendations on, say, diet restrictions (also not as fun!) so are healthier and have better outcomes.

[kgwgk]

> I read it that the invite doesn get you differnces, the colonoscopy itsrlf does.

Differences with what?

Not with the counterfactual where those people didn’t get a colonoscopy! (At least as far as I can tell from the results being discussed here.)

> every single additional person showing up for a screening is a net win.

Maybe. This study doesn’t tell us much about it.

[ricardobeat]

You just did it again.

[hef19898]

Whatever

[kwhitefoot]

> people like JBP, meaning it at least misses the point by a mile.

Who?