Abstract and Introduction
Background: There are limited data on the incidence of pneumonia and pneumonia-related hospitalisation in the IBD population, and on any association of IBD medications with such outcomes.
Aims: To evaluate the impact of IBD medications on the risk of pneumonia, pneumonia-related hospitalisations and death.
Methods: We conducted a retrospective cohort study of IBD patients from the nationwide Veteran Affairs (VA) dataset. The exposure of interest was different IBD medication groups. We estimated the incidence rate of pneumonia, pneumonia-related hospitalisation and mortality based on IBD medication subgroups. We used a multivariable Cox regression to estimate the adjusted hazard ratios (AHR) and 95% confidence intervals (CIs) for these outcomes.
Results: Out of 56 410 patients with IBD, 3759 developed pneumonia, 1489 were hospitalised, and 248 died within 30 days of their pneumonia diagnosis. The crude incidence rates of pneumonia, pneumonia-related hospitalisation and pneumonia-related mortality were 6.47, 2.52 and 0.43, respectively, per 1000 person-years. In multivariable Cox regression analysis, compared to 5-ASA alone, anti-TNF medication was associated with an increased risk of pneumonia (AHR 1.39; 95% CI 1.22–1.59) and hospitalisation (AHR 1.61; 95% CI 1.31–1.98). Use of prednisone in the prior 30 days was associated with increased risk of pneumonia (AHR 2.14; 95% CI 1.92–2.38) and hospitalisation (AHR 2.44; 95% CI 2.08–2.88).
Conclusion: Anti-TNF medications and prednisone use may be associated with increased risk of developing pneumonia and pneumonia-related hospitalisation. Physicians should evaluate the risk–benefit ratio of IBD medications, especially in the elderly population.
Crohn’s disease (CD) and ulcerative colitis (UC), collectively known as inflammatory bowel disease (IBD), are characterised by chronic inflammation of the gastrointestinal tract. The prevalence of IBD is rising globally and in the United States, approximately 3.1 million adults (1.3% of total population) had IBD in 2015.[1,2] While the management of IBD has undergone a transformation in the last two decades with the advent of drugs with novel mechanisms of action, these drugs are also associated with adverse events of which infection is a primary concern. In addition, the prevalence of elderly patients with IBD is also increasing which is significant as the elderly are more prone to infections. Infections are associated with an increased health care burden, hospitalisation, and mortality among patients with IBD[5,6] and thus evaluating the incidence and factors associated with infection is important among the IBD population.
Amongst all infections, pneumonia was found to be the most common infection in both younger and older IBD patients. However, there is a paucity of data on pneumonia among the IBD population, including the incidence, hospitalisation, mortality rate and risk factors influencing these outcomes, especially the role of immunosuppressive medications.[7–9] More importantly, as per Infectious Diseases Society of America (IDSA) guideline, the diagnosis of pneumonia requires various clinical findings, including the presence of an infiltrate on chest X-ray (CXR). To our knowledge, none of the previous studies have looked at individual patients’ clinical findings or CXR results to confirm the diagnosis. They relied solely on the ICD-9 and 10 coding which could be inaccurate.[7,8] Furthermore, there is limited data regarding the consequences of pneumonia, that is hospitalisation rate and mortality.[7–9] With the advent of SARS-CoV-2, it has become critically important to get an accurate determination of the incidence and risk factors associated with the development of pneumonia in the IBD population.
To overcome these limitations, we evaluated the incidence and risk factors of pneumonia and the associated hospitalisation as well as the mortality rate in a nationwide cohort of IBD patients in the Veterans’ Affairs (VA) healthcare system. The VA is an ideal setting to conduct this study, despite the fact that it has an older population with higher smoking rates which may lead to higher incidence rates, as drug exposures are captured accurately and unlike insurance databases, the VA database can be validated internally and individual patient CXRs can be reviewed. Our aims were to evaluate (a) the incidence of pneumonia and pneumonia-related hospitalisation as well as mortality in patients receiving different IBD medications, and (b) the impact of different IBD medications on the risk of developing pneumonia and pneumonia-related hospitalisation.