[Diverticular disease: towards 2020. An evidence-based approach]

Diverticular disease (DD) of the colon has an increasing burden on health service resources, in terms of hospital admissions, mortality and surgery rate. We present an overview of the clinical history of DD, and of the ways that gastroenterologists have to modify it. Prevalence of the disease increases with aging. Most of diverticulosis are occasionally identified on colonscopy, and most of them remain asymptomatic for all life. Only 4% of these subjects develop diverticulitis. However, 4-25% of these patients are expected to present a second episode of diverticulitis, and 15% of them develop complications. Hospitalizations for diverticulitis and relapses of diverticulitis show strong growth (+21% 2013 vs 2003 in USA). The total annual costs for hospitalization for DD in USA are over 2,2 billion of dollars, and in Italy exceed 63 million of euros. In-hospital mortality can reach 0,5%. Diagnosis of diverticulitis is based on clinical history, lab tests and imaging (ultrasonography, CAT). Clinical diagnosis has a sensitivity of 68% and specificity around 98%. According to a meta-analysis, the performance of ultrasonograhy and CAT results very high ("pooled" sensitivity 92-94%, and specificity 90-99%; "pooled" Likelihood Ratio positive 9.6 for ultrasonography and 78.4 for CAT. Likelihood Rato negative 0.09 and 0.06 respectively). Evidences for preventing relapse are poor. Anyway, a very recent meta-analysis on 6 RCTs suggests no role for mesalazine (GRADE SCALE for evidence 3). Non absorbable antibiotics (rifaximin) have been used in two studies (one RCT, one retrospective observational). Data from the two studies suggest some evidence in favour of its use (GRADE SCALE 1). The number of admitted patients is 291. Considering a base-line risk of 19 relapses every 100 patients (5-year observation period), the absolute risk difference is minus 9 patients with relapse (CI 95% -14 a + 3) in the RCT and minus 14 patients (CI 95% -17 a -5) in the observational study. A 2020 preview suggests an exploding interest in assessing the risk factors for relapse (including aspirin and NSAIDs) and identifying the better strategy to reduce it. Further trials are requested, including the use of probiotics alone.