Complications of Ambulatory Procedures: Prevalence and Hospital Outpatient Department Variation.

Ambulatory procedures performed electively in hospital outpatient departments are of increasing complexity and constitute a growing share of total procedure volume. Despite their importance, little is known of the prevalence of complications from routine procedures once patients are discharged. This study utilizes a 100% Medicare Fee-for-Service claims data file for the years 2019-2022 to assess the relative frequency of hospital-based ambulatory procedures and 30-day patient postprocedure emergency room and hospitalization complication rates utilizing the Ambulatory Potentially Preventable Complication (AM-PPC) classification method. AM-PPC is a claims-based method designed to calculate comparative provider rates of complication exclusively for elective ambulatory procedures excluding procedures performed in hospital emergency departments. The authors calculated the mean rate of ambulatory complications by procedure across hospitals and then compared them for variation in hospital-specific procedure complication rates to the mean rate. About 2.1% of patients receiving a procedure performed in a hospital outpatient department had an emergency room or inpatient hospitalization visit within 30 days. Complication event rates varied widely across hospital outpatient departments and within specific procedures. Hip arthroplasty complication rates varied from 0.0% to 7.6% while those for upper genitourinary procedures varied from 1.7% to 14.2%. In conclusion, the complication rate for ambulatory procedures is seen to vary substantially across hospital outpatient departments for well-established, routine procedures. This study provides a baseline of complication rates for ambulatory procedures, which will be essential for future efforts to improve patient safety.