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

ObjectivesTo evaluate whether age is independently associated with greater rate of unanticipated hospital admission within 30days of ambulatory surgery. DesignRetrospective database study. SettingThe 2012 National Surgical Quality Improvement Project data set. ParticipantsAll individuals with outpatient recorded as their status in the data set. MeasurementsThe 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 thefinal model was performed using a conditional tree analysis. ResultsThe 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 30days after ambulatory surgery. ConclusionEven after adjusting for comorbidities, older adults are at greater risk of unanticipated hospital admission within 30days 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.