Canadian Association of General Surgeons and American College of Surgeons evidence based reviews in surgery. 17. The timing of elective colectomy in diverticulitis: a decision analysis.

Question: Is an elective colectomy after the first episode of diverticulitis in patients under 50 years, or after the second episode in patients over 50 years, preferable to a strategy of expectant management until after the fourth episode? Design: A Markov model was used to determine the lifetime risks of death and colostomy, quality of life and costs associated with elective colectomy after the first or second episode of diverticulitis compared with a strategy of expectant management until after the fourth episode of diverticulitis. Base case: Patients aged 35 years and 50 years who had recovered from a nonsurgically treated episode of diverticulitis. Treatment alternatives: Elective colectomy after the first, second, third or fourth episode of diverticulitis. Outcomes considered: The number of colostomies and deaths for each of the strategies for both cohorts. Sources of estimates for probabilities and utilities: Baseline probabilities were derived from the literature, as well as from a population-based cohort of 25 000 patients with diverticulitis whose data were recorded in a statewide hospital discharge database in Washington state. The utilities were derived from the few available studies related to colorectal diseases. Results: Performing colectomy after the fourth episode of diverticulitis rather than after the second episode in patients over the age of 50 years resulted in 0.5% fewer deaths and 0.7% fewer colostomies. In younger patients, performing colectomy after the fourth episode compared with the first episode resulted in 0.1% fewer deaths and 2% fewer colostomies. Sensitivity analysis: One-way sensitivity analysis was performed across all variables. Two-way sensitivity analysis (meaning that 2 variables were varied) was also performed. The risk of death and risk of colostomy after elective surgery and the risk of colostomy as an emergency operation were major determinants of which strategy was superior. Conclusion: This study demonstrates that expectant management is associated with lower rates of death and colostomy compared with a strategy of elective prophylactic colectomy.