Irritable Bowel Syndrome Not Linked To Increased Mortality Risk

In a nationwide prospective cohort study in Sweden, people with irritable bowel syndrome (IBS) had no increased mortality risk, researchers say.

Investigators identified 45,524 patients undergoing a colorectal biopsy at any of Sweden's 28 pathology departments who had a diagnosis of IBS between 2002 and 2016 according to the National Patient Register. They then compared mortality risk in IBS patients to 217,316 age- and sex-matched reference individuals from the general population and 53,228 siblings.

After a median follow-up of 7.3 years, there were 3,290 deaths in individuals with IBS (9.4 per 1,000 person-years) compared with 13,255 deaths in reference individuals (7.9 per 1,000 person-years).

After adjusting for confounders, IBS was not linked to mortality (HR 0.96). Risk estimates were also neutral when patients with IBS were compared to their siblings.

"To our knowledge, there have been no previous studies suggesting IBS is associated with increased mortality," said lead study author Dr. Kyle Staller, director of the GI Motility Laboratory at Massachusetts General Hospital and Harvard Medical School in Boston.

"However, fear about the potential serious nature of bowel symptoms is thought to underlie much of the care seeking among patients with IBS, and some estimates suggest more than 50% of IBS patients fear that their illness may shorten their lifespan," Dr. Staller said by email.

In a separate analysis, researchers examined the role of mucosal appearance for mortality in IBS. The underlying mucosal appearance on biopsy had only a marginal impact on mortality, they report in The American Journal of Gastroenterology.

Researchers also examined mortality in 41,427 patients with IBS not undergoing a colorectal biopsy and found no increased risk of death compared to non-biopsied reference individuals.

When the study team looked at mortality from specific diseases, they found patients with IBS were at a lower risk of death from CVD (HR 0.92); cancer (HR 0.93); and psychiatric diseases (HR 0.81) than reference individuals without IBS.

One limitation of the study is the potential for selection bias in a cohort of individuals undergoing biopsy for a disease that does not require biopsy for diagnosis, the study team notes. Therefore, the study population may represent a subset of patients with IBS in whom suspicion for organic disease is high enough to warrant endoscopic investigation.

"As a field, we have long treated IBS as a debilitating but non-lethal illness," said Dr. Eric Shah of Dartmouth-Hitchcock Health in Lebanon, New Hampshire.

"However, this was largely based on smaller studies and experience in treating IBS—what we have long needed was a large study to help us inform our patients on this risk," Dr. Shah, who wasn't involved in the current study, said by email. "We now have data on over 250,000 total IBS and healthy patients which says that—reassuringly—there is no evidence that IBS increases the risk of death."

Fear of an elevated cancer risk and an increased mortality risk with IBS can drive increased healthcare utilization and repeated testing that might not always be necessary, said Dr. Linda Nguyen, director of neurogastroenterology and motility at Stanford University in California.

"The main take-home message is that patients not die prematurely from IBS nor are they at increased risk of developing malignancies," Dr. Nguyen, who wasn't involved in the study, said by email. "Treatment goals should be aimed at improving quality of life and symptoms rather than 'curing' the disease to prevent future complications."

This does not mean if an individual develops IBS-like symptoms that they should ignore these symptoms particularly if they have alarm features such as blood in their stools, unexplained weight loss, or if they have the new onset of symptoms over the age of 50, said Dr. Anthony Lembo, director of GI motility and functional bowel disorder center at the Beth Israel Deaconess Medical Center in Boston.

"These individuals should seek medical attention," Dr. Lembo, who wasn't involved in the study, said by email. "The data in this study only apply to individuals who received a

—Lisa Rapaport

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