Patients with inflammatory bowel disease (IBD) are more likely to develop influenza compared to people without IBD, a study shows.

The study, “Increased Risk of Influenza and Influenza-Related Complications Among 140,480 Patients With Inflammatory Bowel Disease,” was published in the journal Inflammatory Bowel Diseases.

Patients with autoimmune diseases (conditions in which the immune system attacks the body’s own tissue) tend to have a higher risk of viral infections, some of which may be preventable. But there is limited data available on the incidence and risk of influenza and related complications in patients with IBD.

Also, patients with IBD are often prescribed drugs that suppress the immune system, the effect of which on influenza risk is not known.

Researchers set out to determine the incidence and severity of influenza in IBD patients. They also investigated the effect of medications on influenza risk.

Researchers used data from the MarketScan database.  They studied 140,480 patients with IBD and the same number of non-IBD controls.

There were 2,963 IBD patients with influenza compared to 1,941 non-IBD subjects — indicating that patients with IBD were significantly more likely to develop influenza.

Patients with IBD had a 1.54 times higher risk of developing influenza compared to those without IBD.

Additionally, patients with IBD had a much higher rate of hospitalization because of influenza, a rate of 5.4% compared to 1.85% in patients with influenza without IBD.

As expected, use of systemic corticosteroids (immunosuppressive medication) was found to be independently associated with influenza. Patients taking corticosteroids had a 1.22 times higher risk of developing influenza.

Patients with Crohn’s disease had a slightly higher risk of developing influenza compared to patients with ulcerative colitis, perhaps because they use more immunosuppressive medication.

The researchers concluded, “Inflammatory bowel disease patients had an increased risk of influenza compared with those without IBD and were more likely to require hospitalization. Steroids were the only medication class independently associated with flu risk.”

The study highlights the need for healthcare professionals to make sure that IBD patients are vaccinated against influenza.