Outcomes of initially nonoperative management of diverticulitis with abscess formation in immunosuppressed patients. DIPLICAB study COLLABORATIVE group.

Aim: Management of diverticulitis with abscess formation in immunosuppressed patients (IMS) remains unclear. The main objective of the study was to assess short- and long-term outcomes between IMS and immunocompetent patients (IC). The secondary aim was to identify risk factors for emergency surgery.

Methods: A nationwide retrospective cohort study was performed at 29 Spanish referral centres between 2015-2019 including consecutive patients with first episode of diverticulitis classified as modified Hinchey Ib or II. IMS included immunosuppressive therapy, biologic therapy, malignant neoplasm with active chemotherapy and chronic steroid therapy. A multivariate analysis was performed to identify independent risk factors to emergency surgery in IMS.

Results: A total of 1395 patients were included; 118 IMS and 1277 IC. There were no significant differences in emergency surgery between IMS and IC (19.5% and 13.5%, p = 0.075) but IMS was associated with higher mortality (15.1% vs. 0.6%, p < 0.001). Similar recurrent episodes were found between IMS and IC (28% vs. 28.2%, p = 0.963). Following multivariate analysis, immunosuppressive treatment, p = 0.002; OR: 3.35 (1.57-7.15), free gas bubbles, p < 0.001; OR: 2.91 (2.01-4.21), Hinchey II, p = 0.002; OR: 1.88 (1.26-2.83), use of morphine, p < 0.001; OR: 3.08 (1.98-4.80), abscess size ≥5 cm, p = 0.001; OR: 1.97 (1.33-2.93) and leucocytosis at third day, p < 0.001; OR: 1.001 (1.001-1.002) were independently associated with emergency surgery in IMS.

Conclusion: Nonoperative management in IMS has been shown to be safe with similar treatment failure than IC. IMS presented higher mortality in emergency surgery and similar rate of recurrent diverticulitis than IC. Identifying risk factors to emergency surgery may anticipate emergency surgery.