BOSTON – The risks of readmission and emergency surgery are low for patients with acute diverticulitis initially managed nonoperatively, a population-based, competing risk analysis found.

At a median of 3.9 years (range, 1.7-6.4 years) after discharge among 14,124 patients, only 8% required urgent readmission. Of these, 22% went on to urgent surgery and 20%, to elective surgery after additional episodes.

Among the remaining 12,981 patients with no urgent readmissions, 9% went on to elective surgery, 13% died of other causes, and 78% had no events in follow-up, Dr. Debbie Li said at the annual meeting of the American Surgical Association.

The 5-year cumulative incidence was 9% for readmission, 1.9% for emergency surgery, and 14.1% for all-cause mortality.

"Elective colectomy may not be warranted for the majority of patients in the absence of chronic symptoms or multiple frequent recurrences," she said.

Elective colectomy has traditionally been recommended for patients at high risk for future recurrence and emergency surgery based on the indications of age less than 50 years, complicated disease including perforation and abscess, and two or more episodes of uncomplicated disease. Evidence is building, however, to challenge these indications, and guidelines are evolving, said Dr. Li, a general surgery resident at the University of Toronto.

The current study used administrative data to identify all patients in Ontario, Canada, treated nonoperatively at first hospitalization for diverticulitis from 2002 to 2012. Time-to-event and competing-risk regression analyses were performed, with data adjusted for such potential confounders as sex, medical comorbidity, neighborhood income quintile, rural residency, and calendar year of index admission.

Data are limited on the natural history of diverticulitis, and the few population-based studies that have been conducted have not accounted for competing risks such as elective colectomy or death, Dr. Li said.

The patients’ median age was 59 years, 79% had uncomplicated index disease, 18% had complicated disease (abscess, fistula, and perforation) with no abscess drain, and 3% had complicated disease with an abscess drain.

Young patients had more readmissions than those 50 years and older (10.5% vs. 8.4%; P less than .001), but not more emergency surgery (1.8% vs. 2.0%; P = .52), she said.

For patients older than 50 years, the risk of death by other causes was 10 times the risk of an emergency surgery for diverticulitis (19.5% vs. 2%).

Patients with complicated rather than uncomplicated index disease had more readmissions (12% vs. 8.2%; P less than .001) and urgent surgery (4.3% vs. 1.4%; P less than .001).

In adjusted analyses, young age was associated with more readmissions (hazard ratio, 1.24), but not subsequent emergency surgery (HR, 0.83). Complicated disease (HR, 3.15) and multiple recurrences (HR, 2.41) predicted an increased risk for emergency surgery.

"Young age, complicated disease, and multiple recurrences do infer increased relative risk, but the vast majority (85%) of such patients remain recurrence free," Dr. Li said.

Invited discussant Dr. David Schoetz, professor of surgery, Tufts University, Boston, said, "While it’s reassuring that even complicated diverticulitis can be safely managed without subsequent operation, there still must be a subgroup who should be offered early surgery."

With disease severity more common in younger patients and overall mortality less than 1%, perhaps aggressive surgery would be justified in those younger than 50 years, he suggested.

Dr. Li responded that an administrative database is unable to capture clinical nuances such as which patients had ongoing symptoms, chronic persistent disease, or reduced quality of life, and that a prospective trial would be needed to identify which subgroup of patients will need aggressive surgery.

Older patients, those with more complicated disease, and those with greater medical comorbidities are more likely to undergo urgent surgery, according to ongoing analyses of roughly 4,000 patients, treated during the same time period, but excluded from the current analysis because they underwent surgery at index admission. Previously published work also suggests that patients with a higher body mass index have poorer outcomes.

A recent systematic review of diverticulitis surgery (JAMA Surg. 2014;149:292-303) reported that complicated recurrence after an episode of uncomplicated diverticulitis is rare, occurring in less than 5% of cases. The authors called for existing guidelines to be updated and said that decisions to proceed with elective surgery should be based instead on patient-reported frequency and severity of symptoms.

The complete manuscript of this study and its presentation at the American Surgical Association’s 134th annual meeting, April 2014, in Boston, is anticipated to be published in the Annals of Surgery, pending editorial review.

Dr. Li and her coauthors reported no relevant financial disclosures.

pwendling@frontlinemedcom.com

Data derail dogma of elective diverticulitis surgery