Nationwide Analysis of Adult-Onset Still Disease With and Without Hemophagocytic Lymphohistiocytosis

Introduction Adult-onset Still disease (AOSD) is a rare inflammatory condition with a monophasic, intermittent, or chronic clinical course, and a subset may experience life-threatening complications such as hemophagocytic lymphohistiocytosis (HLH). This study aims to characterize concurrent AOSD and HLH and identify variables independently associated with in-hospital death. Methods We performed a medical records review of AOSD with and without HLH from the 2016–2019 National Inpatient Sample database. We performed a multivariable logistic regression analysis for in-hospital death. Results were reported as adjusted odds ratios (OR adj ). Results There were 5495 hospitalizations with AOSD, of which 340 (6.2%) had HLH. Thirty (9.0%) of the combined AOSD and HLH group died in the hospital compared with 75 (1.5%) of those without HLH. Multivariable analysis in AOSD inpatients showed that disseminated intravascular coagulation (OR adj 6.13), hepatic failure (OR adj 7.16), infection (OR adj 3.72), respiratory failure (OR adj 6.89), and thrombotic microangiopathy (OR adj 14.05) were associated with higher odds of death. However, HLH itself was not an independent predictor of mortality in AOSD population. Conclusions HLH occurred in a small minority of inpatients with AOSD. HLH itself was not an independent risk factor for in-hospital death. Disseminated intravascular coagulation, hepatic failure, infection, respiratory failure, and thrombotic microangiopathy were associated with higher odds of in-hospital death in AOSD. Better awareness of these life-threatening complications may improve hospital outcomes.