The association between physician knowledge and inappropriate medications for older populations.

Background: Older patients are often prescribed potentially inappropriate medications (PIMs) given their age. We measured the association between a physician's general knowledge and their PIM prescribing.

Methods: Using a 2013-2017 cross-sectional design, we related a general internist's knowledge (n = 8196) to their prescribing of PIMs to fee-for-service Medicare beneficiaries, age ≥ 66 years with part D coverage, which they saw in the outpatient setting the year after their exam (n = 875,132). Physician knowledge was based on the American Board of Internal Medicine's (ABIM) Internal Medicine Maintenance of Certification (IM-MOC) exam scores. Medications included 72 PIMs from the American Geriatric Society's Beers Criteria and appropriate alternatives to these medications. Logistic regressions controlled for physicians practice/training characteristics and patient-risk factors.

Results: Annually, 11.0% of patients received a PIM and 57.2% received an appropriate alternative medication. Patients seen by physicians scoring in the top versus bottom quartile were 8.6% less likely (95% confidence interval [CI]: -12.7 to -4.5, p < 0.001) to be prescribed a PIM and 4.7% more likely (95% CI: 1.7 to 7.6, p = 0.001) to be prescribed an appropriate alternative medication. The difference in PIM prescribing grew to 12.1% fewer (95% CI: -15.1 to -9.1) patients when limiting the sample to the 58.9% of patients being prescribed a PIM or appropriate alternative medication. Among patients receiving any medication, this was similar to the percent difference in PIM prescribing between solo and large practices (≥50 physicians, -10.2%, 95% CI: 13.6-6.5, p < 0.001) or between group and academic practices (-11.7%, 95% CI: -15.3 to -7.9, p < 0.001). PIM prescribing was more positively associated with patient characteristics including age, gender, and total number of medications prescribed.

Conclusions: Better physician general knowledge, as measured by an ABIM exam, was associated with fewer PIM prescriptions. Future research should examine whether general educational interventions, such as MOC, effect PIM prescribing.