Hospital admission for complicated diverticulitis is increasing in Italy, especially in younger patients. A national database study

Background: Epidemiological studies show an increasing trend of hospitalization for acute diverticulitis (AD), but data regarding the trend in hospitalization for complicated AD in Italy are scarce. The aim of this study was to analyze the Italian trend in hospitalization for complicated AD, from 2008 to 2015. Methods: Using the Italian Hospital Information System, we identified all patients with complicated colonic AD as a discharge diagnosis. Age- and sex-specific rates for AD as well as type of hospital admission (emergency/elective), type of complication (peritonitis, obstruction, bleeding, abscess, fistula, perforation, sepsis) and type of treatment (medical/surgical), were analyzed. Results: A total of 41,622 patients with a discharge diagnosis of complicated AD were identified. Over the study period the admission rate grew from 8.8 to 11.8 per 100,000 inhabitants. The hospitalization rate was highest for patients ≥ 70 years, but the increase in the admission rate was higher among patients aged ≤ 60 years. There were more males in the group < 60 years and more females in the group ≥ 60 years old. The rate of emergency admissions associated with surgery showed a significant mean annual increase (+ 3.9% per year) in the rate of emergency admissions associated with surgery, whereas elective admissions for surgery remained stable. Peritonitis was the most frequent complication (35.5%). The rate of surgery increased in AD complicated by peritonitis (+ 5.1% per year), abscess (+ 5.8% per year) and decreased for obstruction (- 1.8% per year). Conclusions: From 2008 to 2015, we documented an increasing rate of hospitalization for complicated AD, especially for younger patients, with an increase in surgery for peritonitis and abscess. Further studies are needed to clearly assess the risk factors for complications and risk of surgery.