Comparing patient comorbidity between hospital outpatient department and ambulatory surgery center for arthroscopic surgery

Ambulatory Surgery Centers (ASCs) and Hospital Outpatient Departments (HOPDs) report similar perioperative outcomes for orthopedic surgeries in healthy patients. Patient comorbidity may be an important deciding factor to choose between HOPD and ASC for arthroscopic surgeries that are often painful and need a general anesthetic, with the assumption that sicker patients are being done at HOPD with more resources. However, it is unclear if HOPD patients are truly sicker. Using New York State Ambulatory Surgery Dataset (2010-2015), in patients undergoing shoulder/knee arthroscopies, we assessed for differences in patient comorbidity calculated as Elixhauser Comorbidity Index (ECI) and trend in ECI over time, between HOPDs and ASCs. We also assessed for differences in duration of stay, unplanned hospital admission, 90-day readmissions, and total and regional anesthesia (RA) charges between HOPDs and ASCs. A higher proportion of patients in ASCs were healthy (ECI 0) (97.9% versus 78.4% of patients in HOPDs). Only 1.21% of patients in ASCs had a high ECI score (>= 5) versus 11.9% of patients in HOPDs (p<0.001). The proportion of sicker patients in HOPDs increased from 2010 to 2015 and declined for ASCs. The duration of stay was longer and unplanned hospital admissions lower for HOPDs. 90day readmissions were similar between HOPDs and ASCs. Total and RA charges were higher in HOPDs.