When Dr. Jonathan Vandergrift looked at records for nearly 900,000 Medicare patients, he found something striking: the smarter the doctor, the fewer unnecessary tests that patient tended to receive. The research, published in JAMA Internal Medicine, shows that physicians who scored higher on a knowledge assessment ordered fewer tests and treatments that provide little to no benefit to patients. Together, these so-called low-value services cost the U.S. healthcare system an estimated $100 billion each year.
The study tracked 7,089 outpatient general internists who first took the American Board of Internal Medicine's (ABIM) Longitudinal Knowledge Assessment (LKA) in 2022 or 2023. The LKA is a new option for doctors to stay certified—instead of taking one big exam, they answer 30 questions every quarter and receive feedback on each one. More than 92,000 physicians currently use this pathway.
Vandergrift and his team found that if all general internists ordered low-value services at the same rate as the top-scoring doctors, about 80,000 fewer Medicare fee-for-service patients would receive these services each year. Two tests drove most of the difference: thyroid hormone (T3) testing for patients with hypothyroidism and prostate cancer screening (called PSA testing) for men over 75. Both are among the costliest low-value tests in the country and rarely find anything useful. PSA testing in older men, in particular, often leads to a chain of extra biopsies and treatments that can be painful and expensive.
Despite the savings potential, low-value care was common across all doctor knowledge levels. Roughly 30 percent of patients received at least one low-value service regardless of how their physician scored—including patients of the highest-scoring doctors. The researchers looked at 25 different services, including vitamin D testing without a specific reason, neck artery screenings for people without symptoms, and brain imaging for simple headaches.
Bruce Landon, a professor of healthcare policy at Harvard Medical School who co-authored the study, said the findings add to growing evidence that doctors with stronger medical knowledge tend to produce better outcomes for patients. Past research has shown these doctors have lower hospital readmission rates and a lower risk of death among their patients.
The researchers now want to study whether doctors who improve their scores over the five-year LKA cycle will actually order fewer unnecessary services. "If those who scored lower in the first year increase their knowledge, and therefore their score, over time, will they then order fewer low-value services?" Vandergrift asked. The team hopes the answer could help trim the billions wasted on care that doesn't help patients—and redirect that money toward treatments that do.