Differences by Physician Seniority in Race and Ethnicity and Insurance Coverage of Treated Patients

This cross-sectional study investigates the share of patients who were members of racial and ethnic minority groups or Medicaid enrollees by physician seniority.


Introduction
In a discussed but little-studied practice, senior physicians preferentially treat patients with more generous commercial insurance, whereas junior physicians treat more patients with Medicaid. 1,2  Medicaid has less generous payments but disproportionately includes Black or Hispanic patients.A 2-tiered system by physician seniority could act as an institutional mechanism for racial and economic segregation, limiting access to more experienced physicians.Little evidence exists on the association of physician seniority with patient panel demographics.

Methods
The Harvard University and University of Minnesota institutional review boards approved this crosssectional study with a waiver of informed consent because of the use of observational data, in accordance with 45 CFR §46.This study followed the STROBE reporting guideline.
We analyzed 2017 all-payer claims data from athenahealth, Inc, a medical billing and electronic health record vendor, and 2021 Medicare fee-for-service Part B public use files, 3 the most recent years available.We included physicians with 50 or more patients treated in the period and practices, defined by address, with 4 or more physicians of the same specialty.For each practice, we identified the 2 most junior and 2 most senior physicians using year of medical school graduation, with ties broken randomly.For each physician, we calculated the share of patients treated who were Medicaid (or dually eligible) enrollees and the share from racial and ethnic minority groups (eAppendix 1 in Supplement 1).Physicians were classified into cognitive (eg, primary care or endocrinology), procedural (any surgical-or procedure-predominant specialty), or non-office-based (ie, emergency medicine or radiology) specialties (eTable in Supplement 1).We hypothesized no differences among non-office-based specialists given that these patients and physicians have less choice.We tested for differences in patient panel composition with linear regression models using a dependent outcome of physician-level Medicaid or minority group share of patients and an independent indicator for physician seniority rank (ie, most junior, second most junior, second most senior, and most senior) within each practice, controlling for practice fixed effects (eAppendix 2 in Supplement 1).

+ Supplemental content
Author affiliations and article information are listed at the end of this article.

Discussion
In 2 independent data sets, this cross-sectional study found that senior physicians treated fewer traditionally underserved patients than their junior colleagues within practices.This gap was not present for specialties without scheduled patient visits, suggesting that physician-or practice-level incentives, such as lower reimbursement rates or greater administrative hassles for Medicaid enrollees, may contribute. 4Some differences may also be associated with differences in patient choice or agency.An important limitation is that this analysis is observational, so results should be interpreted as hypothesis-generating associations.
The potential clinical impact of this segregation and its importance for disparities in care require further investigation.Existing literature suggests a mixed association between physician tenure in medicine and patient outcomes.

Figure .
Figure.Difference in Medicaid and Minority Group Patient Percentage by Physician Seniority

Table .
Medicaid and Minority Group Patient Shares by Physician Seniority and Specialty Differences by Physician Seniority in Patient Race and Ethnicity and Insurance PP (95% CI, −2.51 to −2.00 PP).The seniority gap in the fraction of minority group patients was −1.36 PP (95% CI, −1.63 to −1.10 PP) in athenahealth and −0.96 PP (95% CI, −1.21 to −0.70 PP) in Medicare.By specialty group, the largest Medicare share seniority gaps were in procedural specialties (difference, −2.85 PP [95% CI, −3.34 to −2.35 PP] for athenahealth and −3.24 PP [95% CI, −3.61 to −2.86 PP] for Medicare) (Table).There was no seniority gap by Medicaid or minority group for non-office based specialists.