Mehmet Oz heads to the Senate today, where members will consider his nomination to be CMS administrator. Here's what I'm watching for him to address: How Medicare determines what to pay doctors, and how much HHS Secretary Robert F. Kennedy Jr. wants to shake up that process.

Why it matters: The American Medical Association, the largest group representing doctors in the country, and certain specialist physicians may be facing changes they won't like at all.

• Republican ire with the AMA has been building for years.
• But tackling the association's influence over doctor payments — and the incentives those payment rates create — also aligns with Kennedy's quest to root out industry influence from the government and reduce the prevalence of chronic disease in the U.S.
• Interestingly enough, the subject has also drawn interest from people well outside of the MAHA movement, including some who otherwise oppose most of Kennedy's stances.
• Reforms could begin to chip away at the gap between what primary care doctors and specialists are paid, which could ultimately lead to more preventive care and healthier people.

Where it stands: I'll say it from the start: Medicare payment policy is incredibly dense. But it's also incredibly important, and influences reimbursement throughout the rest of the health care system, including commercial insurance.

• Back in November, Stat reported that Kennedy and his team were exploring how to reduce the role the AMA plays in influencing how much services should cost. The Washington Post followed up with a similar report saying Kennedy's stated goal of changing up the payment formula would be to better incentivize primary care and prevention.
• Some experts argue that paying more for surgeries and procedures versus primary care incentivizes performing more of those services — and also deters medical students from going into primary care in the first place.

How it works: The AMA makes money from its copyrights on billing codes used across the medical industry, and the association also includes a powerful panel of doctors that makes payment recommendations to Medicare. Although CMS doesn't have to accept the panel's recommendations, it usually does.

• This panel, called the AMA/Specialty Society RVS Update Committee but referred to as the RUC, has long been criticized as being inherently biased and promoting payment rates that undervalue primary care.

What they're saying: The AMA "has long had an outsized role in the health economy," including through its licensing of CPT codes and the RUC, "whose recommendations have been historically rubber-stamped by HHS," said David Mansdoerfer, a senior HHS official in the first Trump administration.

• "Secretary Kennedy has made reviewing conflicts of interest a top priority — what better place to start than a systematic review of areas that HHS has outsourced policy decisions to activist associations like the AMA and taking corrective action to restore transparency," he added.
• HHS didn't respond to a request for comment.
• The AMA said the RUC "is deeply misunderstood and often mischaracterized," and that "the regulatory process for creating Medicare's payment policies affords hospitals, home health agencies, nursing homes, private health insurers and others the same opportunity as the RUC to provide input to CMS."
• "Primary care physicians play a crucial — and expanding — role in the RUC's highly technical work," the association added.

The big picture: Doctors, including the AMA, really want Medicare payment reform — generally. But any effort to decrease the disparity between primary and specialty care payments that resulted in a significant reduction of payment for certain specialities would likely meet fierce resistance from the industry.

• Specialists tend to make tens of thousands — if not hundreds of thousands — more dollars per year than primary care physicians.
• The industry is still smarting from Congress' failure to include an across-the-board Medicare payment bump to physicians in its spending bill, although members have vowed to include it in future legislation.

What we're watching: Although Medicare payment reform is allegedly something Kennedy is interested in tackling, this is ultimately a CMS issue (or even a legislative one). That means Oz's thoughts on it very much matter.

An attempt to take on the RUC or the AMA more broadly could have a lot of political cover from both sides of the aisle.

• When I asked former senior Trump official Joe Grogan whether the AMA is in trouble, he responded, "God, I hope so."
• Grogan isn't exactly ideologically aligned with Zeke Emanuel, a left-leaning health policy expert who was a health care adviser in the Obama administration. But Emanuel also favors rethinking the status quo.
• "Those physicians have an inherent conflict of interest: They are in effect setting their and their colleagues' pay," Emanuel recently wrote of the RUC in The Atlantic. "It is clear that primary-care physicians deliver life-saving care — and deliver it efficiently. But their compensation does not reflect this utility," he added.

Other unlikely potential allies: Families USA, a patient advocacy group that usually sides with Democrats; the Center for American Progress, a left-leaning think tank; and Arnold Ventures, the billionaire-founded philanthropy that has pushed for drug price and hospital payment reforms that would be unfavorable to those industries.

• All three have pushed for Medicare payment reforms that include changes to the RUC process.

Yes, but: Weakening the role the AMA plays in determining how Medicare values different health care services inherently requires coming up with an alternative method.

• That's easier said than done, especially as there would certainly be a clash between those who wanted to use more market-based measures and those who would want CMS to play a more central role.
• And, of course, taking on the RUC doesn't necessarily mean full-scale overhaul. It could simply mean CMS follows fewer of its recommendations.

Kennedy's response to the measles outbreak spreading across the Southwest has been criticized by experts as inadequate and somewhat awkward. His writing on the disease and its vaccine from four years ago may explain why.

• Kennedy, as HHS secretary, is tasked with both responding logistically to the outbreak and messaging to the public what people can do to protect themselves.
• The answer to the latter, according to health care experts and extensive scientific research, is to get vaccinated. But saying so — or even believing so — would be greatly at odds with what Kennedy wrote only a few years ago.
• Extensive research has found measles vaccines are safe and effective.

Where it stands: Kennedy wrote the forward in a book on the measles published in 2021 by Children's Health Defense, the anti-vaccine group he founded and formerly chaired. The book is subtitled "Thirty-Five Secrets the Government and the Media Aren't Telling You about Measles and the Measles Vaccine."

• Readers of the book "will learn that they have been misled by the pharmaceutical industry and their captured government agency allies into believing that measles is a deadly disease and that measles vaccines are necessary, safe, and effective," Kennedy wrote.
• It "rips the cloak off Pharma industry slogans to reveal a disease that is rarely life threatening and a vaccine that is largely unnecessary but which carries real risks for the children mandated to take them," he added.
• And finally: "Measles outbreaks have been fabricated to create fear that in turn forces government officials to 'do something.' They then inflict unnecessary and risky vaccines on millions of children for the sole purpose of fattening industry profits."

Go deeper: Here are some of the "secrets" the book lists, which are deeply misleading or just inaccurate.

• Measles is "not as dangerous as we are being told and not as prevalent nor rampant," and is "usually just a rash."
• Manufacturers make a lot of money from vaccines, and so do HHS, FDA and CDC employees. And so does the media, which receives "billions of dollars in advertising revenue from the drug companies that make vaccines. It wouldn't be smart to bite the hand that feeds them."
• The measles vaccine "like every other vaccine, can be dangerous or even deadly to some children."
• Vaccines are linked to the rise of autoimmune diseases.
• Within the vaccine business, it's known that "some kids may be seriously injured or killed from vaccines, but, in their judgment, it's worth the risk. After all, it's not their kids."
• The autism-vaccine connection has actually not been disproven.

The bottom line: The measles outbreak has immediately provided a test of Old Kennedy vs. New Kennedy. But although he tuned down his rhetoric during his confirmation hearings, he never claimed to have changed his mind on vaccines.