Natural History of Sigmoid Diverticulitis: The Geneva Cohort Study

Colonic diverticulosis is an increasingly common condition in the Western societies; in our country, a third of the population is affected by the 6th decade and two-thirds by the 9th decade. Fortunately, a majority of patients with diverticulosis remain asymptomatic; diverticulitis, the most common presentation of diverticular disease, has an estimated incidence of 10 patients per 100,000/year.

The diagnosis of sigmoid diverticulitis is usually suspected clinically in a patient presenting with acute lower abdominal pain, associated with an inflammatory syndrome with elevated CRP and/or leukocytes count. The preferred imaging modality to establish definitive diagnosis is computerized tomography (CT) scan with triple (oral, intravenous and intra-rectal) administration of contrast. CT scan may also influence management by demonstrating whether sigmoid diverticulitis is simple (phlegmonous, showing an infiltration of pericolic fat and a thickening of intestinal wall) or complicated (abscess, fistula or peritonitis).

A majority of patients present with simple diverticulitis, and will be conservatively and successfully managed with antibiotics alone. Full colonoscopy is performed eventually, in order to rule out an associated condition, most notably cancer and Crohn's disease. Colonic diverticular disease is usually restricted to the sigmoid colon, and conservative treatment with antibiotics is indicated in cases of a first attack of uncomplicated diverticulitis, the rationale being that a majority of patients treated for a first episode of acute inflammation will eventually recover and have no further problems.

Elective sigmoidectomy is currently recommended in the following clinical situations:

• Patients who had two episodes of uncomplicated diverticulitis.
• Patients who had one episode of complicated (perforated) diverticulitis, with either pericolic of pelvic abscesses (Hinchey stage I and II respectively), fistula formation and/or stenosis.

These guidelines, however, reflect expert consensus rather than scientific evidence; currently, there is no way to predict for each patient the risk for developing subsequent complications and recurrences. Thus, the important question is to determine whether a conservative approach is not simply delaying definitive treatment and expose patients to additional complications and alterations in quality of life.

1. OBJECTIVES

The main objective of this study is to assess the natural history of sigmoid diverticulitis in a cohort of patients living in an urban community, who had radiological and endoscopic evidence of diverticular disease, who benefited initially from adequate antibiotherapy, received dietary counselling, and were followed for a long period of time. In order to do that, we will assess prospectively the following variables:

3.1. Primary endpoints

• Annual rate of recurrent diverticulitis
• Severity and timing of recurrent episodes
• Quality of Life and gastrointestinal symptoms assessed with the GIQLI questionnaire

3.2. Secondary endpoints

• Risk for undergoing emergency surgery
• Surgical morbidity/mortality