LAUSR

Importance Although the incidence of acute appendicitis among adults 65 years and older is high, these patients are underrepresented in randomized clinical trials comparing nonoperative vs operative management of appendicitis; it is unclear whether current trial data can be used to guide treatment in older adults. Objective To compare outcomes following nonoperative vs operative management of appendicitis in older adults and assess whether they differ from results in younger patients. Design, Setting, and Participants This retrospective cohort study used US hospital admissions data from the Agency for Healthcare Research and Quality's National Inpatient Sample from 2004 to 2017. Of 723 889 adult patients with acute uncomplicated appendicitis, 474 845 with known procedure date who survived 24 hours postprocedure and did not have inflammatory bowel disease were included (43 846 who were treated nonoperatively and 430 999 with appendectomy) were included. Data were analyzed from October 2021 to April 2022. Exposures Nonoperative vs operative management. Main Outcomes and Measures The primary outcome was incidence of posttreatment complications. Secondary outcomes included mortality, length of stay, and inpatient costs. Differences were estimated using inverse probability weighting of the propensity score with sensitivity analysis to quantify effects of unmeasured confounding. Results The median (IQR) age in the overall cohort was 39 (27-54) years, and 29 948 participants (51.3%) were female. In patients 65 years and older, nonoperative management was associated with a 3.72% decrease in risk of complications (95% CI, 2.99-4.46) and a 1.82% increase in mortality (95% CI, 1.49-2.15) along with increased length of hospitalization and costs. Outcomes in patients younger than 65 years were significantly different than in older adults, with only minor differences between nonoperative and operative management with respect to morbidity and mortality, and smaller differences in length of hospitalization and costs. Morbidity and mortality results were somewhat sensitive to bias from unmeasured confounding. Conclusions and Relevance Nonoperative management was associated with reduced complications in older but not younger patients; however, operative management was associated with reduced mortality, hospital length of stay, and overall costs across all age groups. The different outcomes of nonoperative vs operative management of appendicitis in older and younger adults highlights the need for a randomized clinical trial to determine the best approach for managing appendicitis in older patients.