Long-term mortality and recurrence in patients treated for colonic diverticulitis with abscess formation: a nationwide register-based cohort study.

PURPOSE: The study aimed to investigate long-term mortality, recurrence, and death related to recurrence for patients admitted with acute diverticulitis with abscess formation (Hinchey stage Ib-II). METHODS: The cohort was identified by linking administrative registers for all Danish citizens in years 2000-2012. Patients were identified from ICD-10 discharge codes and stratified according to treatment (antibiotics, percutaneous abscess drainage, or surgery). RESULTS: From 6,641,672 persons, 3148 patients were identified with acute diverticulitis with abscess formation. Survival was comparable between treatment groups with a 1-year survival of 81-83% and a 5-year survival of 66-67% (p = 0.66). Glucocorticoid usage prior to admission increased risk of mortality with hazard ratio 1.64 (95%CI 1.39-1.93), 1.77 (1.20-2.63), and 1.92 (1.07-3.44) for the antibiotics, drainage, and operative treatment group, respectively. Drainage treatment increased risk of recurrence with sub-distribution hazard (SDH) of 1.52 (1.19-1.95) and operative treatment decreased risk with a SDH of 0.55 (0.32-0.93), both compared with antibiotic treatment (p = 0.0001). Recurrence occurred in 23.6% (18.5-30.1%) of patients in the drainage group, 15.5% (13.9-17.3%) in the antibiotics group, and 9.1% (5.1-16.1%) in the operative group. Recurrence-related mortality was 2.0% (0.9-4.4%) for the drainage group, 1.1% (0.7-1.8%) for the antibiotics group, and 0.6% (0.1-4.3%) for the operative group (p = 0.24). Most recurrences and recurrence-related mortality occurred within the first year after primary admission. CONCLUSIONS: This study with complete national data revealed a high mortality and recurrence rate after diverticular abscesses. Survival was comparable between treatment groups, but patients treated with drainage had significantly higher risk of recurrence.