None of your links provides data on spurious denials. The third link does provide this statistic:

"Over a six-year period between 2019 and 2025, almost half of a large set of denied health insurance claims in New York state were reversed when the cases reached independent review organizations, comprised of clinicians unaffiliated with insurers"

But that doesn't get into the reasons why the claims were denied in the first place. It doesn't tell us anything about bona fide spurious denials vs. improperly filed claims (mistakes in the paperwork), clerical errors, or clients placed under investigation for claiming too early (after applying) or too often (making a lot of spurious claims), or care providers who do the same.

Insurance companies are concerned with adverse selection and moral hazard. A client who files a lot of claims shortly after getting insurance raises the suspicion that they were not honest about their health prior to applying. Similarly, a client who claims every drug a pharmacy carries raises other suspicions.

Of course, most clients aren't like that, but a not-insignificant minority are, and a small number of clients can file a very large number of claims.

It's both.

Medical fraud is like retail stock shrinkage or fraudulent credit card charges -- no one on the customer side is aware of it, because it's handled on the other side and baked into pricing.

But there are substantial amounts of both straight fraud and too aggressively up-coding / over-billing.

The meta problem is that the because of the nature of the industry (legitimate volume dwarfs fraud), it's more financially impactful to pull levers that impact legitimate volume (read: prior auth requirements).

The anti-fraud systems are also pretty robust. As you'd imagine, insurers have been dealing with this for more than a few decades by now.

This is a great answer.

I am deeply offended by your allegation. Not everyone who disagrees with you is a shill. I would not make the same accusations about you, nor would I act as if I can estimate the probability that you are. HN's commentary guidelines address this.

You can consider my mistake to be in conceptualizing the cost of "medical services" too narrowly, as just the medicine, and not the providers' surrounding administration. To that end I take your point. In theory, at least. Do you know how much this has? In particular, you refer to the back-and forth negotiation of claims--on what do you base this claim?

They’re locked into a red queen race. Providers merge to gain scale and negotiation power. Insurers merge to gain scale and negotiation power. The ACA encouraged scaling up to drive down unit costs, but it just resulted in companies scaling up to protect their margins.

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I believe you but I'm interested in the studies mentioned in your first sentence.

GLP1s don't or shouldn't cost $1K+/month.

Gastric bypass surgery happens once. Many bypass patients require lifelong prescription nutritional supplements and all require lifelong lab monitoring.

Ulcer risks increase severalfold.

High risk of hernias, osteoporosis and complications thereof.

It's not just surgery and no immediate cost. But then again, any of those issues are options for denial, so...

Not really. They're highly regulated in their offerings, and the government mandates how much they spend on care vs. overhead. They can't effectively compete so the only option is to negotiate slightly higher payments to providers and PBMs every year so they can take more profit in absolute terms.

Stop thinking of insurers/providers as separate agents, and start thinking of them as building blocks for financial engineers.

Law binds individual fictions, but not compound ones. Until we start making financial engineering basically illegal, these types of "happy, profit juicing conjunctions" will be the norm.