Early Computed Tomography Imaging and Clinical Outcomes in Hospitalized Patients with Acute Diverticulitis: A Propensity-Matched Multicenter Cohort Study.

Background/Objectives: Computed tomography (CT) is the gold-standard diagnostic modality for acute diverticulitis, yet the association between early CT imaging and short-term clinical outcomes among hospitalized older adults has not been evaluated in a large multicenter propensity-matched cohort. We assessed whether early CT abdomen/pelvis (within 24 h of admission) was associated with improved short-term outcomes compared with delayed or absent CT among adults aged ≥65 years hospitalized with acute diverticulitis. Methods: We conducted a retrospective cohort study using the TriNetX US Collaborative Research Network through February 2026. Early CT was defined as CT abdomen/pelvis performed within 24 h of the index hospitalization. Patients underwent 1:1 propensity score matching using demographic, comorbidity, diverticulitis-related, medication, and laboratory variables. The primary outcome was 30-day all-cause mortality. Results: Among 86,214 eligible patients, 62,478 received early CT and 23,736 did not. After matching, 22,840 patients remained in each cohort. Early CT was associated with lower 30-day mortality (RR 0.72, 95% CI 0.62-0.84), 90-day mortality (RR 0.78, 95% CI 0.70-0.87), bowel surgery within 30 days (RR 0.81, 95% CI 0.73-0.90), sepsis (RR 0.76, 95% CI 0.69-0.84), acute kidney injury (RR 0.85, 95% CI 0.78-0.92), ICU admission (RR 0.79, 95% CI 0.72-0.87), and 30-day readmission (RR 0.86, 95% CI 0.80-0.93). Early CT was also associated with higher rates of percutaneous abscess drainage (RR 1.37, 95% CI 1.21-1.55) and shorter hospital length of stay (5.4 vs. 6.8 days; mean difference -1.4 days, 95% CI -1.6 to -1.2). Conclusions: Early CT imaging within 24 h of admission was associated with improved short-term outcomes among older adults hospitalized with acute diverticulitis, including lower mortality, reduced need for bowel surgery, lower rates of sepsis and acute kidney injury, shorter hospital stay, and higher utilization of percutaneous abscess drainage. These findings support guideline recommendations for prompt diagnostic CT imaging in this population and suggest that early CT may facilitate timely risk stratification, source control, and management optimization.