Is nonoperative management of appendicitis safe and effective in multi-morbid patients?

The purpose of this study was to (1) compare post-treatment outcomes of operative and nonoperative management of acute appendicitis in multi-morbid patients and (2) evaluate the generalizability of prior clinical trials by determining whether outcomes differ in multi-morbid patients compared to the young and healthy patients who resemble prior clinical trial participants. We conducted a retrospective cohort study using the National Inpatient Sample from 2004 to 2017. We included 368,537 patients with acute, uncomplicated appendicitis who were classified as having 0 or 2+ comorbidities. We compared inpatient morbidity, mortality, length of stay, and costs using propensity scores. Unmeasured confounding was addressed with probabilistic sensitivity analysis. Overall, 5% of patients without comorbidities were treated nonoperatively versus 20% of multi-morbid patients. Compared to surgery, nonoperative management was associated with a 3.5% decrease in complications (95% confidence interval 3%-4%) for multi-morbid patients, but there was no significant difference for patients without comorbidity. However, nonoperative management was associated with a 1.5% increase in mortality for multimorbid patients (95% confidence interval 1.3%-1.7%). Costs and length of stay were lower for all patients treated with surgery. Probabilistic sensitivity analysis showed that results were robust to the effects of unmeasured confounding. Our results raise concerns about the generalizability of clinical trials that compared nonoperative and operative management of appendicitis because (1) those trials enrolled mostly young and healthy patients, and (2) results in multi-morbid patients differ from outcomes in younger and healthier patients.