Fulfillment status of hypertriglyceridemia and hypofibrinogenemia in children with hemophagocytic lymphohistiocytosis and risks of multiple organ dysfunction syndrome and early mortality.

Background: Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening disorder. How to stratify high risk patients is one of the current challenges for the treatment of HLH. HLH patients usually fulfill multiple but not all eight diagnostic criteria. Different combinations of the fulfilled criteria may naturally cluster into previously undescribed subsets or phenotypes that may have different pathophysiology and demonstrate different risks for a poor outcome. The objectives of this study were to identify HLH subgroups according to the fulfillment of diagnostic criteria and evaluate the risk of multiple organ dysfunction syndrome (MODS) and 30-day mortality for subgroups. We retrospectively collect medical records of patients with discharge diagnosis of HLH between June 2015 and October 2018 from a tertiary children's hospital in China. Latent class analysis was used to identify class defining variables from HLH diagnostic items, and subgroups were defined according to different combinations of the class defining variables.

Results: Triglyceride and fibrinogen were identified as the class defining variables. When evaluated in combinations, patients with hypertriglyceridemia and normal fibrinogen levels during hospitalization had the lowest risks for MODS (27.8%, OR = 1) and 30-day mortality (18.8%, OR = 1), and patients with normal triglyceride and hypofibrinogenemia had the highest risks for MODS (86.2%, OR = 16.24, P = 0.0002) and 30-day mortality (57.1%, OR = 5.78, P = 0.0187). The fulfillment status of hypertriglyceridemia and hypofibrinogenemia within 72 h of hospital admission was also associated with the risk of adverse outcomes.

Conclusions: The fulfillment status of hypertriglyceridemia and hypofibrinogenemia were associated with the risks of MODS and 30-day mortality among pediatric HLH patients. Further studies are needed to validate this association and investigate its clinical utility in the severity evaluation for HLH.