ImportanceThe optimal treatment of acute uncomplicated appendicitis in older adults with frailty is not defined.ObjectiveTo examine outcomes associated with treatment strategies for acute uncomplicated appendicitis in older adults with or without frailty.Design, Setting, and ParticipantsThis retrospective cohort study used National Inpatient Sample data from adults 65 years or older with a diagnosis of uncomplicated appendicitis from January 1, 2016, to December 31, 2018. Data were analyzed from July to November 2023. The National Inpatient Sample database approximates a 20% stratified sample of all inpatient hospital discharges in the US.ExposuresStudy patients were categorized into 3 groups: nonoperative management, immediate operation, and delayed operation.Main Outcomes and MeasuresClinical outcomes, including hospital complications and in-hospital mortality, were assessed among older adults with and without frailty, identified using an adapted claims-based frailty index.ResultsA total of 24 320 patients were identified (median [IQR] age, 72 [68-79] years; 50.9% female). Of those, 7290 (30.0%) were categorized as having frailty. Overall, in-hospital mortality was 1.4%, and the incidence of complications was 37.3%. In patients with frailty, multivariable analysis showed both nonoperative management (odds ratio [OR], 2.89; 95% CI, 1.40-5.98; P < .001) and delayed appendectomy (OR, 3.80; 95% CI, 1.72-8.43; P < .001) were associated with increased in-hospital mortality compared with immediate appendectomy. In patients without frailty, immediate appendectomy was associated with increased hospital complications compared with nonoperative management (OR, 0.77; 95% CI, 0.64-0.94; P = .009) and lower hospital complications compared with delayed appendectomy (OR, 2.05; 95% CI, 1.41-3.00; P < .001).Conclusions and RelevanceIn this cohort study of older adults with uncomplicated appendicitis, outcomes differed among management strategies based on frailty status. Routine frailty assessments incorporated in the care of older adult patients may help guide discussions for shared decision-making.