Patient vs provider characteristics impacting hospital lengths of stay after total knee or hip arthroplasty.

This study aims to identify whether patient-level or provider-level characteristics are most influential on a patient's length of stay in the acute care hospital. A data set containing a nationally representative sample of inpatient discharge abstracts was used. Multilevel linear regression models were used to evaluate the associations between patient-level and provider-level characteristics on patients' lengths of stay. The target population included 322,894 discharges with a primary procedure code for primary total knee arthroplasty and 193,553 discharges for total hip arthroplasty. The variables associated with the greatest increases in length of stay were a higher comorbidity level among patient level attributes (+17.4%) and low surgeon volume among provider-level characteristics (+18.8%). Provider-level characteristics, particularly provider volume, had a greater impact on length of stay.