Antibiotics tied to increased risk of older-onset IBD

"Older adults are the fastest growing IBD subpopulation," Dr. Adam Faye of NYU Grossman School of Medicine, in New York City, noted during a press briefing ahead of the Digestive Disease Week.

Using Denmark's national database, Dr. Faye and his colleagues analyzed the records of 2.3 million adults aged 60 to 90 years followed from 2000 to 2018. During that time, 10,773 new cases of UC and 3,825 new cases of CD were recorded.

Any antibiotic use was associated with a 64% higher risk for developing IBD (incidence rate ratio, 1.64). The risk was dose-dependent, with one, two, three, four or five+ course of antibiotics yielding IRRs of 1.27, 1.54, 1.66, 1.96 and 2.35, respectively.

The risk for IBD onset was highest in the one to two years following an antibiotic prescription, but the risk persisted at two to five years.

All types of antibiotics were associated with increased IBD risk in older adults, with the exception of nitrofurantoin, which is commonly used for urinary-tract infections.

Antibiotics usually prescribed for gastrointestinal infections, including fluoroquinolones, nitroimidazoles and macrolides, were the most likely to be associated with a new IBD diagnosis.

"In older adults, we think that environmental factors are more important than genetics," Dr. Faye said in a news release. "When you look at younger patients with new diagnoses of Crohn's disease and ulcerative colitis, there's generally a strong family history. But that is not the case in older adults, so it's really something in the environment that is triggering it."

The findings have implications for antibiotic stewardship that goes beyond prevention of multidrug-resistant pathogens.

"Antibiotic stewardship is important; but avoiding antibiotics at all costs is not the right answer either. If you're not sure what you are treating, I would be cautious. If patients are coming in with clear infections, and they need antibiotics, they should not be withheld because of these findings," Dr. Faye said in the release.

The study was conducted in partnership with the Danish National Center of Excellence PREDICT Program. The authors have no relevant conflicts of interest.