title: Clinical presentation and risks.
abstract: BACKGROUND
  A recurrent episode of diverticulitis is a new distinct episode of acute inflammation after a period of complete remission of symptoms. Outdated literature suggested a high recurrence rate (>40%) and a worse clinical presentation with less chance of conservative treatment. More recent studies showed a more benign course with no need toward an aggressive policy of treatment.
  
  
  METHODS
  We report data from revised literature and from our study: a 4-year multicenter retrospective and prospective database analysis of 743 patients hospitalized for acute diverticulitis (AD) treated medically or surgically and then followed for a minimum of 9 years.
  
  
  RESULTS
  The literature showed a recurrence rate of 25-35% at 5 years of follow-up, with a reduced risk of severe complications (i.e. perforations), a risk of subsequent emergency surgery of 2-14% and a risk of stoma and related death of 0-2.7%. Several risk factors of recurrence have been advocated: family history, abscess, severe CT stage, comorbidities (renal failure, collagen vascular disease) and nonsteroidal anti-inflammatory drugs. Young age is still a matter of debate. These studies have different limitations: retrospective, lack of definition of AD, small number of patients, long recruiting time, short follow-up, study population or hospital-system based. In our study of 320 followed-up, medically treated patients, 61% were asymptomatic and 22% complained of chronic symptoms: the 12-year actuarial risk of recurrence, emergency surgery, stoma and death was 21.2, 8.3, 1 and 0%, respectively. Recurrence was related to very young age (<40 years) and more than 3 previous episodes of AD.
  
  
  CONCLUSIONS
  This study confirms the benign course of diverticulitis treated conservatively, with a low long-term risk of serious complications and death, and does not support an aggressive surgical policy to prevent them.
authors.affiliation: Department of General Surgery, Galliera Hospital, Genova, Italy. gian.andrea.binda@galliera.it
authors.forename: Gian Andrea
authors.initials: GA
authors.lastname: Binda
authors.forename: Antonio
authors.initials: A
authors.lastname: Amato
authors.forename: Alberto
authors.initials: A
authors.lastname: Serventi
authors.forename: Alberto
authors.initials: A
authors.lastname: Arezzo
mesh_terms: D004239:Diverticulitis, Colonic / Q000150:complications / Q000453:epidemiology* / Q000473:pathology* / Q000628:therapy; D006801:Humans; D012008:Recurrence; D012307:Risk Factors; D016896:Treatment Outcome