Older Adults and Unanticipated Hospital Admission within 30 Days of Ambulatory Surgery: An Analysis of 53,667 Ambulatory Surgical Procedures

J Am Geriatr Soc. 2015 Aug;63(8):1679-85. doi: 10.1111/jgs.13537. Epub 2015 Jul 22.


Objectives: To evaluate whether age is independently associated with greater rate of unanticipated hospital admission within 30 days of ambulatory surgery.

Design: Retrospective database study.

Setting: The 2012 National Surgical Quality Improvement Project data set.

Participants: All individuals with "outpatient" recorded as their status in the data set.

Measurements: The primary outcome of interest was all-cause hospital admission in the 30-day period after surgery. Multivariate models were constructed to control for covariate bias. Assessment of interactions of terms in the final model was performed using a conditional tree analysis.

Results: The final analysis included 53,667 ambulatory surgical cases. There were 1,370 (2.5%, 99% confidence interval (CI) = 2.4-2.7%) hospital admissions among the cases evaluated. After adjusting for potential confounders, age (<70 vs ≥70) was independently associated with hospital admission (odds ratio = 1.54, 99% CI = 1.29-1.84). A classification tree analysis of the cases without postoperative morbidity identified age (<60 vs ≥60) as an important decision point leading to greater likelihood of admission (P < .001) within 30 days after ambulatory surgery.

Conclusion: Even after adjusting for comorbidities, older adults are at greater risk of unanticipated hospital admission within 30 days of ambulatory surgery. Renal failure, chronic obstructive pulmonary disease, current cancer treatment, diabetes mellitus, and history of amputation or revascularization were also associated with greater likelihood of hospital admission. Interventions to improve transitions of care for older adults after ambulatory surgery are needed.

Keywords: admission; ambulatory; older adult; surgery.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Ambulatory Surgical Procedures / statistics & numerical data*
  • Female
  • Follow-Up Studies
  • Humans
  • Illinois / epidemiology
  • Incidence
  • Male
  • Middle Aged
  • Patient Admission / statistics & numerical data*
  • Postoperative Complications / epidemiology*
  • Postoperative Period
  • Retrospective Studies
  • Risk Factors
  • Time Factors