recurrence and virulence of colonic diverticulitis in immunocompromised patients background to evaluate the probability of recurrence and the virulence of colonic diverticulitis correlated with immunocompromised statusmethods nine hundred thirtyone patients admitted in a single tertiary referral university hospital over a 14year period were included patients were divided into 2 groups group 1 166 immunosuppressed patients and group 2 765 nonimmunosuppressed patients the variables studied were sex age american society of anesthesiologist status reasons of immunosuppression eg chronic use of corticosteroids transplant recipients and diseases affecting the immune system severity of the diverticulitis episode recurrence emergency and elective surgery and morbidity and mortality ratesresults two hundred thirteen patients underwent an emergency operation during the first hospitalization and 26 patients in further episodes one hundred thirtysix patients developed 1 or more recurrent episodes of diverticulitis the overall recurrence rate was similar in both groups patients in group 1 with a severe first episode presented significantly higher rates of recurrence and severity without needing more emergency surgery mortality after emergency surgery was 333 in group 1 and 159 in group 2 p 004conclusions after successful medical treatment of acute diverticulitis patients with immunosuppression need not be advised to have an elective sigmoidectomy