Hemophagocytic lymphohistiocytosis in inflammatory bowel disease: a nationwide analysis

Hemophagocytic lymphohistiocytosis (HLH) is a rare but life-threatening immune dysregulation disease. Patients with inflammatory bowel disease (IBD) can become profoundly immunocompromised due to immunosuppressive therapy, hence increasing the risk of viral infections that can trigger HLH. However, data on the association between IBD and HLH remains limited. We used data from the National Inpatient Sample (2012–2019) utilizing International Classification of Diseases (ICD)-9 or ICD-10 codes to identify individuals with IBD, either Crohn’s disease (CD) or ulcerative colitis (UC), and HLH. The primary outcome was to compare the prevalence of HLH among patients with IBD with those without IBD. Secondary outcomes included in-hospital mortality, mean hospital length of stay, and description of HLH-associated triggers in IBD patients. A total of 513,322 hospitalizations included a diagnosis of IBD, 188,297 had UC and 325,025 had CD. Compared to the general population, patients with IBD were older (median age of 52 vs. 49 years, p