Day for night: Hospital admissions for day surgery patients

Objective. The volume of outpatient surgeries performed in ambulatory surgery centers (ASCs) has increased steadily since the 1980s. There is concern among providers and the general public about the relative safety of outpatient surgery. The objectives of this study were: (1) to make use of the ASC patient data available for the first time in California in 2005 to investigate healthcare quality and (2) to characterize the occurrence of complications for ASC services, as measured by post-procedure hospital admission, in terms of volume, timing, and risk factors.

Methods. For this study we linked and analyzed two of the administrative patient data sets collected by the state of California during 2005: the newly available Ambulatory Surgery Center Patient Data and the Patient Discharge Data submitted for all inpatient discharges from California-licensed hospitals. The ASC records were matched to the inpatient records using the social security number. A post-ASC admission was defined as the first inpatient admission that occurred within 15 days following the ASC service date. Descriptive statistics were utilized to characterize the timing of readmissions and most frequent admitting diagnoses and procedures. Logistic regression was used to identify risk factors for admission such as patient acuity (total Charlson Comorbidity Index score), source of payment, type of procedure, and type of ASC facility, controlling for patient demographics).

Results. In 2005, a total of 2,552,177 day surgeries were performed in California. Of these 57,687 (2.3%) had a subsequent hospital admission within 15 days. The most frequent admitting diagnoses were complications of surgical procedure; heart disease; and complication of a device, implant or graft. Ninety percent came to the hospital from home and 40% were admitted via the hospital's emergency room. Only 14% of the patients were admitted immediately (within a day), while over half the patients were admitted more than a week post procedure. Admissions for complications of procedures and devices were equally likely to occur immediately at any time during the 15 days, but admissions for infections increased with time elapsed. After controlling for patient demographics, risk factors for admission included patient acuity, ASC association with a hospital, and type of procedure.

Conclusions. This study highlights the need for follow-up of day surgery patients for a week or more following their procedures. It demonstrates the utility of using administrative patient data to assess the safety of outpatient medical care.