Reducing inappropriate emergency department and avoidable hospitalization rates: assessing the influence of medical group practice characteristics.

(1) Practices that are physician-owned and practices that use Electronic Health Records (EHRs) have lower nonemergent emergency department (ED) rates and lower emergent-primary care treatable ED rates. (2) Medical practices with more nurse practitioners or physician assistants per physician have higher emergent-primary care treatable ED and higher ambulatory care sensitive (ACS) rates, but their nonemergent ED rates do not differ statistically from those of other practices. (3) The ability to provide and manage accessible, coordinated care declines as medical practices grow larger and more complex.