Incidence rate and clinical outcome of severe COVID-19 in Inflammatory Bowel Disease patients in a population-based setting

Abstract Background The broad use of immunosuppressants and biologicals in Inflammatory Bowel Disease (IBD) patients increases the susceptibility to severe infections, and possibly COVID-19. Recently, in a Swedish population-based study it was suggested that IBD patients are at an increased risk of hospitalization for COVID-19, although course of COVID-19 did not differ from controls. Data on the outcome of COVID-19 in IBD patients from heavily affected regions remain, however, limited. South-Limburg has the second highest COVID-19 mortality rate in the Netherlands. We aimed to determine the incidence rate and outcome of severe COVID-19 in IBD patients in a population-based setting in South-Limburg. Methods We identified all IBD patients who presented at the emergency department (ED) of the only two hospitals covering the whole South-Limburg region with COVID-19 associated symptoms between February 27 and November 1, 2020. Confirmed COVID-19 diagnosis was defined by a combination of COVID-19 associated symptoms and either a positive SARS-CoV-2 PCR or a CT-CORADS score ≥4. As primary outcome, the incidence rate of severe COVID-19 (i.e. confirmed COVID-19 diagnosis requiring hospitalization, and/or resulting in ICU admission or death) was determined. Baseline characteristics and data on COVID-19 course were collected. At present, the total IBD population in South-Limburg is set at 4980 patients. Results During a follow-up of 3384 person-years, a total of 61 IBD patients (1.22%) presented with COVID-19 associated symptoms at one of the two hospital’s ED. Of these, 18 IBD patients (0.36%; 11 UC, 7 CD) fulfilled the criteria for severe COVID-19, corresponding to an incidence rate of 5.3 per 1000 person-years. Furthermore, 12/18 patients were using immunosuppressive medication for their IBD. Mean age at time of admission was 64.5 years (SD: 10.8) and 55.6% were male. All hospitalized patients had at least one comorbidity (with ≥ 1 comorbidity in 13/18 patients (72.2%)), cardiovascular disease being most prevalent (12/18). Mean BMI at time of admission was 27.3 (SD: 4.2). Thirteen patients (72.2%) required oxygen support and three patients (16.7%) ICU admission (of which two needed mechanical ventilation), translating to an incidence rate of 0.9 per 1000 patient-years for ICU admission. Median length of hospitalization was 11 days (IQR: 5.3–18.3). No IBD patients died due to severe COVID-19. Conclusion The incidence rate of severe COVID-19 among IBD patients in a population-based setting in a heavily affected region was 5.3 per 1000 person-years. Despite frequent use of immunosuppressive medication and high region-specific mortality rates, clinical outcomes of severe COVID-19 were comparable to the general population and in line with recent literature.