Which of the following complications is most associated with diverticulitis?

Perforation is the complication most commonly associated with diverticulitis due to the inflamed diverticula, which can become necrotic and ultimately perforate the colonic wall. This can lead to peritonitis, which is a serious condition requiring urgent surgical intervention.

Diverticulitis involves the formation of small pouches (diverticula) in the colon wall, and inflammation of these pouches can lead to complications such as abscess formation, fistula, and perforation. When perforation occurs, it allows bowel contents to spill into the abdominal cavity, causing widespread infection and significant morbidity.

The other options, such as peptic ulcers, gallbladder stones, and appendicitis, do not have a direct relationship with diverticulitis. Peptic ulcers are primarily linked to factors such as Helicobacter pylori infection or long-term NSAID use, while gallbladder stones relate to biliary system issues. Appendicitis is an entirely different condition related to inflammation of the appendix, not the diverticula. Thus, perforation stands out as the key concern in the context of complications arising from diverticulitis.