@gerryp I am working on a detailed diverticulitis guide with a flow chart of complications, data matrix, reference list, glossary, etc. It is not ready for publishing yet but one data point that came up over and over was that about 75% of Free Perforations (open flow of feces into the abdominal cavity) happen on the patient's first episode of diverticulitis. The synopsis is basically that you either have a spot/spots of weakness in the colon that is susceptible to this, or you don't. So if you've had multiple episodes with no Free Perforation, you are less likely to have one. Plus they think the scaring from healing of previous episodes makes it harder to have a Free Perforation. It came from what they reference as: "The Chapman Study" - Transition rates from Phlegmon to Perforation; "First-Episode" paradox data (75%); long-term recurrence of free air. https://pubmed.ncbi.nlm.nih.gov/16192818/ (Complicated diverticulitis: is it time to rethink the rules?)

FYI.