Background
As a measure of quality, ambulatory surgery centers have begun reporting rates of hospital transfer at discharge. However, this may underestimate patient’s acute care needs after care. We conducted this study to determine rates and evaluate variation in hospital transfer and hospital-based, acute care within 7 days among patients discharged from ambulatory surgery centers.
Methods
Using data from the Healthcare Cost and Utilization Project, we identified adult patients who underwent a medical or surgical procedure between July 2008 and September 2009 at ambulatory surgery centers in California, Florida, and Nebraska. The primary outcomes were hospital transfer at the time of discharge and hospital-based, acute care (emergency department visits or hospital admissions) within 7-days expressed as the rate per 1,000 discharges. At the ambulatory surgery center level, rates were adjusted for age, sex, and procedure-mix.
Results
We studied 3,821,670 patients treated at 1,295 ambulatory surgery centers. At discharge, the hospital transfer rate was 1.1/1,000 discharges (95% CI, 1.1–1.1). Among patients discharged home, the hospital-based, acute care rate was 31.8/1,000 discharges (95% CI, 31.6–32.0). Across ambulatory surgery centers, there was little variation in adjusted hospital transfer rates (median=1.0/1,000 discharges [25th–75th percentile=1.0–2.0]), while substantial variation existed in adjusted hospital-based, acute care rates (28.0/1,000 [21.0–39.0]).
Conclusions
Among adult patients undergoing ambulatory surgery center care, hospital transfer at discharge is a rare event. In contrast, the hospital-based, acute care rate is nearly 30-fold higher, varies across centers, and may be a more meaningful measure for discriminating quality.