Successful nonoperative management of uncomplicated appendicitis: predictors and outcomes.

Background: Our objective was to identify predictors of successful nonoperative management (NOM) of uncomplicated appendicitis. We hypothesized that the absence of diabetes, absence of an appendicolith, short duration of symptoms, absence of systemic inflammation, and low modified Alvarado score would predict successful NOM.

Methods: We performed a retrospective cohort analysis of 81 consecutive patients who underwent NOM of uncomplicated appendicitis. Successful NOM was defined as resolution of appendicitis with antibiotics alone and no recurrent appendicitis within 180 days. Patients with successful NOM (n = 36) were compared with patients who failed NOM (n = 45). Multivariable logistic regression was used to identify predictors of successful NOM, expressed as odds ratios (ORs) with 95% confidence intervals. Model strength was assessed by calculating area under the receiver operating characteristic curve (AUC).

Results: Patient age (35 years), the American Society of Anesthesiologists class (2.0), and Charlson comorbidity index (0.0) were similar between groups. Independent predictors of successful NOM were duration of symptoms prior to admission >25 hours: OR 4.17 (1.42-12.24), maximum temperature within 6 hours of admission <37.3°C: OR 8.07 (1.79-36.38), modified Alvarado score <4: OR 9.06 (1.26-64.93), and appendiceal diameter <13 mm: OR 17.55 (1.30-237.28); model AUC: 0.81 (0.72-0.90).

Conclusions: Patients with a longer duration of symptoms prior to admission were more likely to have successful NOM. Other independent predictors of successful NOM included lower temperature, lower modified Alvarado score, and smaller appendiceal diameter. These findings provide a framework for clinical decision-making and large-scale derivation and validation of a model to predict successful NOM of uncomplicated appendicitis.