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

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). 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). 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. 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.