# Reoperation and mortality following elective surgery for chronic and recurrent colonic diverticular disease: A nationwide population-based cohort study

## TL;DR

This study examines reoperation and mortality rates after elective surgery for chronic and recurrent colonic diverticular disease in Denmark, finding that the risks have decreased over time and are influenced by patient age and hospital contacts.

## Contribution

The study provides population-based evidence on surgical outcomes for chronic and recurrent colonic diverticular disease, identifying predictors of reoperation and mortality.

## Key findings

- The 90-day reoperation rate after elective surgery for crDD was 18.0%, declining by 30% over 25 years.
- Mortality after elective surgery was 1.6%, decreasing by 74% over the study period.
- Patients aged ≥80 years had 18 times higher mortality than those aged <60 years.

## Abstract

The ideal treatment for chronic and recurrent colonic diverticular disease (crDD) remains unresolved, partly due to lacking evidence regarding surgical safety. This study evaluated 90-day reoperation and mortality rates following elective surgery for crDD and explored predictors for reoperation and mortality.

This national cohort study included all patients with crDD undergoing elective colonic resection or stoma formation in Denmark from 1996–2021. Outcomes were the 90-day cumulative incidence proportion (CIP) of reoperation and mortality, and predictors were explored in Cox proportional hazard models.

Among 35,174 patients with crDD, 3,584 (10%) underwent elective surgery. The 90-day reoperation rate was 18.0%; mortality was 1.6%. During the 25-year period, the reoperation rate declined 30%, from 19.5% to 13.8%, and mortality declined 74%, from 2.7% to 0.7%. Among 2,942 patients with colonic resection and no stoma formation, the reoperation rate due to anastomotic leak was 3.0% overall and 0.9% in the most recent years. Mortality was 18 times higher in patients aged ≥ 80 years versus those aged < 60 years (CIP 8.0% versus 0.4%). The reoperation rate was increased in patients with ≥ 4 hospital contacts or ≥ 3 admissions compared to patients with fewer contacts, while mortality was not associated with the number of hospital contacts before surgery.

Elective surgery in crDD was safe with careful patient selection. The risk of reoperation due to anastomotic leak was very low. Patients with most hospital contacts had an increased reoperation rate, supporting consideration for elective surgery early in patients with disabling diverticular disease.

The online version contains supplementary material available at 10.1007/s00384-025-04915-9.