Abstract
BACKGROUND: Dysregulated host response is an important cause of critical illness. Coagulation reaction is the most primitive response and can be used to assess patient status. Coagulation reactions may be amplified in very old patients (VOPs). This study aimed to demonstrate coagulation reactions in critically ill VOPs by linking cytokines, coagulation, and fibrinolytic processes. METHODS: We analyzed 33 critically ill VOPs admitted to our hospital, with an average age of 91.97. Laboratory test results were collected and double checked. In-hospital mortality, Intensive Care Unit (ICU) stay, and length of in-hospital stay (LOS)-associated variables were assessed using a generalized additive mix model. Smooth curves and interaction tests were used to quantify statistical interactions. RESULTS: The in-hospital mortality rate was 45.5% in this study. The D-dimer level was correlated with ICU stay [risk ratio (RR), 1.39; 95% confidential interval (CI), 1.16-1.67] and LOS (RR, 1.75; 95% CI, 1.19-2.57). Other function or quantity indices, such as platelet (PLT), prothrombin time (PT), activated partial prothrombin time (APTT), and thrombomodulin (TM), were all correlated with clinical outcomes. After the link between coagulation reaction and the outcomes was constructed, it was revealed that, compared to lower level of IL-6, under high level of IL-6, elevated TM was likely to be associated with tissue plasminogen activator inhibitor complex (t-PAIC) elevation, which probably promoted the production of D-dimer (RR, 3.216; 95% CI, 1.840-4.592). CONCLUSION: D-dimer levels are associated with outcomes in VOPs with critical illness. There is a certain link between inflammatory cytokines and the coagulation process. Under high IL-6 levels, the elevated TM may contribute to the increased t-PAIC, which contributes to the higher D-dimer level. Conversely, under low IL-6 levels, elevated TM levels are associated with reduced t-PAIC levels.