LAUSR

Supplemental digital content is available in the text. Background Multispecialty clinical settings are increasingly prevalent because of the growing complexity in health care, revealing challenges with overlaps in expertise. We study hospitalists and inpatient specialists to gain insights on how physicians with shared expertise may differentiate themselves in practice. Purpose The aim of this study was to explore how hospitalists differentiate themselves from other inpatient physicians when treating patient cases in areas of shared expertise, focusing on differences in patient populations, practice patterns, and performance on cost and quality metrics. Methodology We use mixed-effects multilevel models and mediation models to analyze medical records and disaggregated billing data for admissions to a large urban pediatric hospital from January 1, 2009, to August 31, 2015. Results In areas of shared physician expertise, patients with more ambiguous diagnoses and multiple chronic conditions are more likely to be assigned to a hospitalist. Controlling for differences in patient populations, hospitalists order laboratory tests and medications at lower rates than specialists. Hospitalists’ laboratory testing rate had a significant mediating role in their lower total charges and lower odds of their patients experiencing any nonsurgical adverse events compared to specialists, though hospitalists did not differ from specialists in 30- and 90-day readmission rates. Practice Implications Physicians with shared expertise, such as hospitalists and inpatient specialists, differentiate their roles through assignment to ambiguous diagnoses and multisystem conditions, and practice patterns such as laboratory and medication orders. Such differentiation can improve care coordination and establish professional identity when roles overlap.