Adults with inflammatory bowel disease (IBD) have an increased risk of serious viral infections compared to the general population, a study suggests.
This risk was found to be highest among younger adults, those with active disease, and patients who have been treated with thiopurines.
The study, titled “Increased incidence of systemic serious viral infections in patients with inflammatory bowel disease associates with active disease and use of thiopurines,” was published in the United European Gastroenterology Journal.
Serious viral infections (SVIs) are generally defined as viral infections that require hospitalization and/or lead to permanent organ damage. While there has been some research into these infections in IBD, the risk factors have not been rigorously determined.
In this study, researchers analyzed data from 2,645 patients with IBD, 18 and older, who had been seen at a referral IBD center between 2005 and 2014.
Most of the individuals (68.6%) had Crohn’s disease, 44.3% were male, and the median age was 34.4 years. The researchers excluded people with ongoing chronic viral infections (hepatitis and HIV).
Among the study’s population, the researchers identified 31 instances of SVIs (not including asymptomatic viral infections detected in association with IBD flares). The researchers calculated that the incidence rate of SVIs in this population was 2.02 per 1,000 person-years.
The most common viruses involved in these infections were Epstein-Barr virus (EBV, best known for causing mono), varicella-zoster virus (which causes chicken pox), herpes simplex virus, and cytomegalovirus (CMV, which doesn’t usually cause symptoms in adults, but is known to be a risk for fetuses).
Then, the researchers used data from the French National Hospital Discharge Database to estimate the occurrence of SVIs in the general population.
They calculated that SVI risk was three times higher among people with IBD. The risk among younger adults (age 18–34 years) with IBD was five times higher than in the general population.
“Clinicians need to be aware of the substantially increased risk of SVI in patients with IBD, which had previously remained unclear,” Laurent Beaugerie, MD, PhD, a professor at Saint-Antoine Hospital, and study co-author, said in a press release. “Young IBD patients are the most vulnerable to the development of SVIs, as they are less likely to have been exposed to viruses such as EBV or CMV before. They will therefore mount a less effective immune response.”
The researchers investigated the SVI risk among people with IBD by comparing those who did get SVIs to a subset of those who did not. They found a 3.35 times higher risk of SVIs among people with clinically active disease and a 3.48 times increased risk among those who had been exposed to thiopurines.
Thiopurines — sometimes referred to as immunomodulators — include azathioprine and 6-mercaptopurine. Generally, these medications are used in IBD because they can reduce the activity of the immune system, but this also can make patients more susceptible to SVIs.
“The relation between IBD drugs and SVIs is especially concerning, as presently, hospitalisation due to the serious complications that accompany the disease is the main cost associated with the management of IBD,” Beaugerie said.
As with any medication, there are pros and cons. For instance, the researchers noted in their paper that, “Thiopurines promote more SVI than anti-TNF agents, but the converse is true for opportunistic bacterial infections.”
“In an ideal word,” they added, “the risk of SVI in patients with IBD could get closer to that of the general population with the use of IBD drugs that prevent IBD-related SVI by way of sustained mucosal healing, whilst not promoting SVI via immunosuppressive effects.”
The study highlights the need for continuous research into new strategies to effectively treat IBD while minimizing complications, the researchers said.