Predictors of treatment failure in CT-confirmed uncomplicated acute diverticulitis discharged from the emergency department: a systematic review

Background: Emergency discharge is an established option for selected adults with uncomplicated acute diverticulitis. Treatment failure is difficult to predict accurately. This focused review examined baseline clinical, laboratory, and computed tomography predictors alongside outpatient outcomes. Methods: Original studies published through 31 May 2026 were examined for computed tomography confirmation, outpatient management, and subsequent deterioration. Ten outpatient studies were summarized descriptively. Broader prognostic cohorts were considered separately because their populations and outcomes differed from immediate emergency discharge. Results: Selected outpatient cohorts recorded low admission rates, including 2/70, 3/66, 4/155, and 4/140 patients in four studies. A randomized outpatient trial recorded hospitalization in 8/242 participants without antibiotics and 14/238 receiving antibiotics. Persistent pain and oral intolerance accounted for several treatment escalations. Imaging associations were imprecise and differed between studies. Different outcome definitions and follow-up periods restricted comparisons of failure frequencies across treatment protocols. Broader cohorts identified free fluid, female sex, elevated C-reactive protein, systemic comorbidity, vomiting, and prolonged symptoms as prognostic signals. Conclusions: Outpatient outcomes were better after structured selection and follow-up. Inflammatory burden, imaging abnormalities, and symptom persistence warrant particular attention. The data supports individualized assessment rather than a universal discharge score, with explicit separation of readmission, complicated progression, and recurrent episodes when interpreting treatment failure across different clinical settings.