IntroductionThe popularity of nonoperative management for acute appendicitis is based on the untested assumption that it offers a lower risk alternative to surgery in patients who are at high risk for morbidity and mortality with appendectomy. We hypothesized that patients who were at a high risk with appendectomy would also be at a high risk for complications following nonoperative management. MethodsThis is a retrospective cohort study of patients with acute, uncomplicated appendicitis in the 2004–2017 National Inpatient Sample. We used a logistic regression model to predict the risk of morbidity or mortality following appendectomy and applied this model to predict the risk of patients managed nonoperatively. High risk was defined as ≥2 standard deviations above the mean predicted risk of morbidity or mortality. We used inverse probability weighting of the propensity score to compare outcomes of nonoperative versus operative management for high-risk patients. ResultsThe sample included 21,242 high-risk patients with a median age of 68 years (interquartile range 57–78), and 31% were managed nonoperatively. Compared to surgery, nonoperative management was associated with a 9% decrease in complications (95% confidence interval [CI] 7%–10%), 2% increase in mortality (95% CI 2%–3%), $10,202 increase in hospital costs (95% CI $9,065–$11,339), 3-day increase in length of stay (95% CI 2–3), and 9% greater likelihood of discharge to skilled nursing facilities (95% CI 8%–10%). ConclusionNonoperative management of acute appendicitis in high-risk patients may reduce morbidity but increase mortality, duration of hospitalization, discharge to skilled facility, and costs. Surgeons should exercise caution when considering nonoperative management in these vulnerable patients.