LAUSR

In 1864, a frontier physician named Andrew Taylor Still watched helplessly as 3 of his own children died of bacterial meningitis. There was little he could have done. Louis Pasteur had articulated his germ theory only a few years before, and Alexander Fleming would not discover penicillin for another 64years. Without effective therapies, the medical establishment at the time used unproven and dangerous therapies that Still abhorred. Over the decades that followed, Still developed an alternative philosophy of medicine, one that focused on healing through manual manipulation of the musculoskeletal system. Still called this philosophy osteopathy, and in 1892, founded the first osteopathic (Doctor of Osteopathic Medicine [DO]) medical school in Kirksville, Missouri. To date, there are 38 osteopathic medical schools and more than 141 000 osteopathic physicians who practice alongside their allopathic (Doctor of Medicine [MD]) colleagues in the United States (1). In their article, Miyawaki and colleagues (2) evaluate whether the quality and costs of care differ between hospitalized Medicare patients treated by allopathic or osteopathic physicians. In this retrospective assessment, the authors used Medicare fee-for-service data among persons who were hospitalized between 2016 and 2019 and cared for by a hospitalist physician. They then compared whether the type of physician (allopathic or osteopathic) affected 30-day readmissions, length of stay, and health care costs (Part B spending). After multivariable adjustment, there were no differences in 30-day mortality (9.4% vs. 9.5%), readmissions (15.7% vs.15.6%), length of stay (4.5 vs. 4.5days), and health care spending ($1004 vs. $1003). Robust subgroup and secondary analyses similarly failed to show meaningful differences in patient outcomes or cost. Although allopathic and osteopathic medical schools differ somewhat in the type of education they provide and the type of student they enroll, Miyawaki and colleagues’ findings show that these differences are not associated with differences in the quality or costs of care their graduates provide, at least to elderly patients in the inpatient setting. Given that osteopathic medical schools now enroll one quarter of all current medical students in the United States, and whose graduates now account for 11% of the U.S. physician workforce (3), these findings are important and warrant a closer examination of the similarities between allopathic and osteopathicmedicine. Although often described as 2 distinct philosophies, modern osteopathic and allopathic medicine have more commonalities than differences. First, data show that the average Medical College Admissions Test score for matriculants to allopathic and osteopathic medical schools are both well above the national average (512 for allopathic, 504 for osteopathic; mean 500) (4, 5). Second, as Miyawaki and colleagues note, both allopathic and osteopathic medical schools have standardized and substantially similar curricula that require accreditation from governing bodies recognized by the U.S. Department of Education. In fact, the accreditation standards for osteopathic and allopathic medical schools have converged over time and are now remarkably similar (6). Although most osteopathic physicians become licensed by completing the Comprehensive Osteopathic Medical Licensing Examination of the United States, approximately 60% of osteopathic students complete at least step 1 of the United States Medical Licensing Examination, where their first-time pass rate is similar to that of allopathic students (94% vs. 96% in 2021) (7). Third, the graduate medical education that osteopathic and allopathic physicians receive has become increasingly standardized. Historically, many osteopathic physicians have obtained residency training in programs accredited by the American Osteopathic Association. Yet by 2014, only 40% of graduates matched into such programs, and since 2020, all residency programs have been accredited by the Accreditation Council for GraduateMedical Education, which ensures that the same educational standards apply to all programs (8). Although many continue to extoll the “distinctiveness” of osteopathic medicine, the precise difference between the professions has become increasingly difficult to identify. Historically, the distinguishing characteristic that has most obviously defined osteopathic physicians from their allopathic colleagues is the use of osteopathic manipulative treatment. However, recent surveys have shown that most osteopathic physicians do not use osteopathic manipulative treatment in their practice (9). Beyond osteopathicmanipulative treatment, differences between allopathic and osteopathic physicians are even harder to find. In the early years after Still’s development of osteopathy, osteopathic physicians regarded pharmacotherapy suspiciously and were slower to adopt modern scientific principles than their allopathic colleagues. Yet today, both allopathic and osteopathic physicians practice evidenceand science-based clinical medicine. Similarly, although osteopathic training focuses on providing holistic, patient-centered care, osteopathic medicine can hardly claim a monopoly on these terms and ideas as they now permeate the modern health care milieu. Altogether, the functional distinction between allopathic and osteopathic physicians has become almost indistinguishable. Despite the quantitative and qualitative equivalence between allopathic and osteopathic physicians, medicine has often been reluctant to accept them into their highest ranks. Data from the National Resident Matching Program show that applicants from osteopathic medical schools are less likely to match into their preferred specialty compared with their allopathic counterparts (10). Disparities grow more pronounced with more competitive medical specialties, and many of the most famous and storied institutions in medicine list many fewer osteopathic physicians on their residency roster or faculty list than may be expected based on the prevalence of osteopathic physicians. Yet, Miyawaki and colleagues’ work shows that