Place of service and the volume-outcome relationship: evidence from eye surgeries.

Surgeries have increasingly moved into the outpatient setting, yet training in the non-hospital setting is rare. Using Medicare claims from 1999 through 2013 on 4,117,141 cataract surgeries, 153,148 retina surgeries, and 91,276 glaucoma surgeries, this research studied whether the relationship between surgeon volume and adverse patient outcomes differed by facility type for eye surgeries. Regression analyses demonstrated a strong association between surgeon volume and patient outcomes for all three types of surgeries. Moving from the lowest to a higher surgeon-volume quintile corresponded with a 9-27% decrease in the odds of complications. However, these volume-outcome relationships did not statistically differ based on whether a procedure was rendered in a hospital versus an ambulatory surgery center or rendered in a high-volume versus a low-volume facility, underscoring the importance of case turnover for quality.