Healthcare and politics have undoubtedly become intertwined in 2025 as the year saw the longest government shutdown on record due to partisan disagreements over extending ACA tax credits for health insurance.
In a research paper published in October, Stanford (Calif.) University’s Woojin Kim, PhD, researcher and assistant professor of political economy explored the extent to which party affiliation shapes the way physicians practice medicine.
Looking at a representative sample of physicians who submitted claims for reimbursement to Medicare, the federal health insurance program for people age 65 and older, Dr. Kim tracked annual spending per patient from 1999 to 2019. He then identified the party affiliation of 28% of those physicians, around 309,000 doctors, by looking up their campaign contributions in a database of political donations.
Here are 10 things to know about the research:
1. Republican and Democratic physicians initially billed Medicare similar amounts for services rendered. However, beginning in 2004, their patterns began to diverge. By 2019, Republican physicians were spending on average approximately 13%, or $70, more per patient annually than their Democratic counterparts.
2. Dr. Kim estimates that if Republican physicians billed the same as Democratic ones, public spending on Medicare would have been $6.2 billion lower in 2019 alone.
3. The bulk of the partisan spending gap was driven by younger physicians, rather than older ones. Younger Republican physicians specifically, identified as those who began making political donations in the mid-2000s, tended to “practice more aggressively” than their Democratic counterparts.
4. Dr. Kim found that this divergence primarily centers around differences in beliefs about what care or treatments are appropriate. He determined that if a group of Republican or Democratic physicians with the same specialties were to see patients in the same geographic area for the same conditions, Republican physicians would still be likely to spend more, especially on elective procedures.
5. Republican and Democratic physicians were equally likely to respond to financial incentives, such as administering more profitable drugs.
6. Other surveys and research considered by Dr. Kim have found that Republican and Democratic physicians place different emphasis on different values. Republican physicians tend to place less emphasis on clinical guidelines and more on physician autonomy.
7. Republican physicians provided more low-value treatments that provide “little benefit to patients” and that clinical guidelines recommend against, according to Dr. Kim. This further suggests an alignment between political affiliation, values and medical practice.
8. For example, Dr. Kim found that Republican physicians were significantly more likely than Democratic ones to prescribe chemotherapy for cancer patients in the final two weeks of life, which Dr. Kim writes is a “common indicator of overly aggressive treatment, since it is expensive, tough on patients and ultimately provides little benefit in these cases.”
9. While the exact cause of the divergence in practice between Democratic and Republican physicians can not be explained definitively by the study, it demonstrates that the mid-2000s marked the beginning of a period of “intense polarization” over healthcare policy, harkening back to feuds over Medicaid expansion and the promotion of evidence-based medicine under the Affordable Care Act.
10. Dr. Kim remains wary of attributing the split directly to political influence.
“It’s hard to make a casual argument,” he said, adding that younger cohorts of both Republican and Democratic physicians have become more divided in their medical school training. “I think that’s an obvious next question: How much does training explain these differences?”
