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NEW YORK (Reuters Health) - Diverticulosis, a common condition that causes small pouches in the walls of the intestines, might not be as dangerous as doctors have thought.
The pouches are usually harmless. But sometimes they become inflamed and infected, in a painful condition known as diverticulitis.
Experts have thought that about one in four patients with diverticulosis would eventually develop diverticulitis. But a new study suggests the actual risk may be much lower.
"The little pouches that form in the wall of the colon are incredibly common and with the increased emphasis on preventive care we do a lot of colonoscopies," Dr. Brennan Spiegel told Reuters Health. "We find a lot of people who have these sacs in their colon."
Spiegel, who was the senior author of the new study, is an associate professor of medicine at the David Geffen School of Medicine at the University of California, Los Angeles.
Fewer than 5 percent of adults under age 40 have these pouches, but by age 85, more than 65 percent of people are affected.
Spiegel said that very little is actually known about the normal behavior of these pouches. But when a pouch does become inflamed, "it can be serious and might need surgery to fix."
"At the very least it requires antibiotics and some intensive medical therapy," he said.
Doctors have accepted the idea that one-quarter of patients with these pouches would eventually develop inflammation.
"The text books and review articles that go back to the 1940s all say the same thing, that if you have one of these pouches in your colon then there's up to a 25 percent chance that it can become infected or complicated or even rupture," Spiegel explained.
But this notion of a 25 percent rule didn't make sense to his team - it seemed too high.
"If that were true, our hospitals would be absolutely overflowing with people with diverticulitis, and they're not," Spiegel said.
He and his colleagues wanted a better sense of the real numbers in order to provide more reliable statistics to newly diagnosed patients.
To learn more, they studied 2,222 patients from the Veterans Affairs Health System in Los Angeles who had been diagnosed with diverticulosis. None of the patients had any symptoms of the condition when it was diagnosed; instead, doctors noticed the pouches while the patients were having a colonoscopy for some other reason.
Using information from medical records, Spiegel's team tracked these patients for an average of almost seven years and published their findings in the December issue of Clinical Gastroenterology and Hepatology.
Of those 2,222 patients, 95 (4.3 percent) developed diverticulitis. Not all of those cases were actually confirmed by a CT scan, however, so the researchers couldn't be sure the patients' symptoms were actually from an inflamed pouch.
When the researchers counted only cases that were confirmed by a CT scan or during an operation, only 23 patients (about 1 percent) actually developed diverticulitis.
The researched also discovered that patients who were diagnosed with diverticulosis at a younger age had a higher risk of developing diverticulitis, compared to patients in whom the pouches were diagnosed later in life.
The study was supported by Shire Development LLC. Shire, a pharmaceutical company, was at one point trying to develop a drug to treat diverticulitis.
There were some limitations to the study. For instance, most of the patients were male. The authors say, however, that other studies have shown that the risk of diverticulitis is similar in men and women. Also, they admit, some of the information in patients' medical records may have been inaccurate.
Spiegel hopes his new research leads to some changes in how physicians treat diverticulosis, adding that current suggestions to add fiber and avoid things like nuts, seeds and popcorn aren't evidence-based.
"The next steps are dissemination of this information, rewriting textbooks and reeducating physicians so they can have rational evidence-based discussions with patients so they don't feel like the sword of Damocles is hanging over their head because they've been given this diagnosis." Spiegel said.
SOURCE: bit.ly/1gm8taR Clinical Gastroenterology and Hepatology, online July 15, 2013.