Different letters, same results: a comparison of milestones among US allopathic and osteopathic residents

Allopathic physicians, those with a Doctor of Medicine (MD) degree, may be unfamiliar with training distinctions with a Doctor of Osteopathic Medicine (DO) degree. Concerns about differences in medical training between DO and MD students may lead to biases against DOs as applicants for entry into residency or fellowship programs. This bias may be associated with lower acceptance rates into certain programs, with several competitive specialties matching <1 % of DO applicants. The potential for disparate treatment could lead to shortages in certain specialties. There is a lack of evidence that competency assessments of DO residents differ from those of MDs when it comes to patient care and outcomes.

This study aimed to compare Milestone assessments across Accreditation Council for Graduate Medical Education (ACGME) competencies (Patient Care [PC], Medical Knowledge [MK], Practice-based Learning and Improvement [PBLI], Interpersonal and Communication Skills [ICS], Professionalism [PROF], and Systems-based Practice [SBP]) of residents who attended US allopathic (MD) vs. osteopathic (DO) medical schools, hypothesizing that there would be no differences throughout residency.

We analyzed Milestone achievements of residents in 3-year programs from the four largest medical specialties in the 2016 and 2017 Match: Family Medicine, Internal Medicine, Pediatrics, and Emergency Medicine. We excluded residents who graduated from international medical schools and programs that exclusively had either osteopathic- or allopathic-trained residents to control for potentially confounding effects. We extracted Milestone data for two cohorts of categorical residents who entered training in July 2016 and July 2017. These cohorts were chosen to avoid the effects of the COVID-19 pandemic and to utilize a single assessment instrument, Milestones 1.0. Milestone scores were compared at the initial and penultimate assessment periods. For each competency domain, by specialty separately, we applied a generalized estimating equations model to account for the correlation among Milestone ratings repeated over time for each resident nested within a training program.

Among 13,544 eligible residents, 31 % were DO graduates. At the initial assessment in the 2016 cohort, DOs had lower Milestone means than MDs in eight areas: Family Medicine MK; Internal Medicine MK, SBP, PBLI, and ICS; and Pediatrics PC, SBP, and PROF. DOs had higher Milestone means than MDs in two areas: Emergency Medicine PC and SBP. By the penultimate assessment, DOs had lower Milestone means than MDs in only three areas (Pediatrics PC, MK, and SBP), and higher Milestone means in all 6 areas for Emergency Medicine. On initial assessment in the 2017 cohort, DOs had lower Milestone means than MDs in seven areas: Family Medicine MK; Internal Medicine PC, MK, SBP, PBLI, PROF, and ICS. DOs had higher Milestone means than MDs in one area: Emergency Medicine MK. By the penultimate assessment, the only significant differences were lower Milestone scores for DOs in Family Medicine MK and PBLI. The absolute value of the differences ranged from 0.05 to 0.12.

Osteopathic- and allopathic-trained residents in four medical specialties demonstrate similar Milestone assessments throughout their training. Small, statistically significant differences found in Milestone assessments favored either MDs or DOs; however, no consistent trends were seen by year or specialty.