Increased risk of obstructive lung disease in inflammatory bowel disease: A population‐based cohort study

Background and aims: Inflammatory bowel disease (IBD) is associated with disease manifestations in organs other than the gastrointestinal tract. In this study, we aimed to estimate the odds of obstructive lung disease (OLD) before IBD onset and the risk of OLD after IBD onset. Methods: In a nationwide population-based Danish cohort study from 1999 to 2018, individuals with IBD and OLD were identified using the Danish registries. Between 2003 and 2013, 24,238 individuals with IBD were identified and matched 1:10 with non-IBD individuals. Logistic regression was used to estimate the prevalence odds ratio for OLD before IBD onset. Time-to-event analysis was performed to explore the risk of OLD after IBD onset. In a sensitivity analysis, the time-to-event analysis was repeated using the composite outcome OLD and the separate outcomes, chronic obstructive pulmonary disease (COPD), asthma, and bronchiectasis. Results: Individuals with IBD were 60% more likely to have OLD before onset (adjusted odds ratio: 1.60, 95% confidence interval [CI]: 1.53-1.67). Furthermore, their risk of OLD was more than 40% higher after IBD diagnosis (adjusted hazard ratio [aHR]: 1.43, 95% CI: 1.37-1.49). The sensitivity analysis increased the risk to 60% (aHR: 1.63, 95% CI: 1.53-1.73). Similar results were found for COPD and asthma separately, whereas the risk of bronchiectasis increased more than 2-fold (aHR: 2.44, 95% CI: 1.91-3.11). Conclusion: The odds of OLD before- and the risk following an IBD diagnosis were increased. We encourage physicians to be vigilant of pulmonary symptoms in persons with IBD and gastrointestinal symptoms in individuals with OLD.