title: A novel index of elevated risk of inpatient hospital admission immediately following outpatient surgery.
abstract: OBJECTIVE
  Patients with increasing comorbidities are at increased risk of admission to an inpatient facility after outpatient surgery.
  
  
  METHODS
  Data from operations performed in hospital-based and freestanding ambulatory surgery centers in New York during 1997 were obtained under the Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project.
  
  
  METHODS
  Of the 783 558 patients eligible for inclusion in this study, 4351 were discharged directly for short-term hospitalization (1:180), and 19 died (1:41 240). We performed a split-half analysis by randomly assigning the study sample to an analysis half for estimation or a holdout half for testing.
  
  
  METHODS
  We developed an outpatient surgery admission index from independent predictors of immediate hospital admission using the following point values: 65 years or older (1), operating time longer than 120 minutes (1), cardiac diagnoses (1), peripheral vascular disease (1), cerebrovascular disease (1), malignancy (1), seropositive findings for human immunodeficiency virus (1), and regional (1) or general anesthesia (2).
  
  
  RESULTS
  Increasing scores were associated with higher odds of admission relative to scores of 0 or 1. For scores of 4 or higher, the odds ratio was 31.96 (95% confidence interval, 26.29-38.86), and 2.8% of these patients were discharged to the hospital. For the holdout half of the data set, scores of 4 or higher had an odds ratio of 34.62 (95% confidence interval, 28.55-41.97).
  
  
  CONCLUSIONS
  The proposed outpatient surgery admission index provides an evidence-based guide to assist clinicians and the health care systems in which they work in identifying patients at higher risk of immediate hospital admission.
authors: Department of Anesthesia, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. fleishel@uphs.upenn.edu
authors: Lee A
authors: LA
authors: Fleisher
authors: L Reuven
authors: LR
authors: Pasternak
authors: Alan
authors: A
authors: Lyles
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000556:Ambulatory Surgical Procedures / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007297:Inpatients / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009518:New York / Q000453:epidemiology; D016017:Odds Ratio; D010343:Patient Admission / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000453:epidemiology*; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States