The Study In Clinical Application Of Plasma D-dimer In H7N9 Avian Influenza

Background and AimsThe avian virus of H7N9 is a subtype of the influenza virus which is the first discovered in our country in 2013. Patients infected with H7N9 viruses have been shown to present with fever, cough and dyspnea, most of them rapidily progress to severe pneumonia, acute respiratory distress syndrome (ARDS), and multiple organ failure, accompanying with the high mortality, which has caused a serious threat to public health. There is urgent need to discover biomarkers monitoring the progression and predicting the prognosis of H7N9. In this study, we investigated the application value of plasma D-dimer in the evaluation the severity and prediction of prognosis in H7N9 and provided objective evidence for clinicans to judge the severity and prognosis of H7N9, based on the retrospective analysis of the changes of plasma D-dimer levels in 109 H7N9 infected patients from Hangzhou.MethodsThe clinical data of 109 H7N9 infected patients hospitalized in the First Affiliated Hospital of Zhejiang University from March 2013 to June 2015 were collected. The patients were divided into low risk group, medium risk group and high risk group according to the PSI, and meanwhile grouped into the survival group and the nonsurvival group depending on the prognosis. At the same time,20 H1N1 infected patients and 31 healthy subjects were selected as control groups. Plasma D-dimer levels were compared in different groups. We retrospectively analyzed clinical characteristics, coexisting diseases, acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) scores, and studied the correlation between D-dimer and PSI and APACHE Ⅱ. Receiver operating characteristic (ROC) curve was used to evalate the application value of D-dimer in predicting the mortality of H7N9 infected patients. The relationship between baseline plasma D-dimer levels and the survival rates in H7N9 infected patients was analyzed by Kaplan-Meier survive curve.ResultsThe plasma D-dimer levels of H7N9 patients were significant statistically higher than that of the H1N1 patients and healthy subjects (both P<0.001). The plasma D-dimer levels of low risk group, medium risk group and high risk group were 2415(120-26290),5700(1588-57872), and 9880(237-65200) ug/L FEU. There were significant statistically differences of plasma D-dimer levels among 3 groups (all P< 0.05), and plasma D-dimer levels would increase with the raise of risk level. The plasma D-dimer levels were significant statistically higher in the nonsurvival group than the survival group (P<0.001). In the survival group, plasma D-dimer levels on the discharge day were significantly lower than that of the first day of admission (P<0.001), but no significant differences were observed during the time; In the nonsurvival group, plasma D-dimer levels had increased dramatically from the day 7 to 14 of admission, and had decreased significantly from the day 14 to 21 of admission, the differences reached statistical significance (both P<0.05). Plasma D-dimer levels were positively correlated with inflammatory indexes of hypersensitive C-reactive protein (HsCRP) and procalcitonin (PCT), and were positively correlated with liver indexes (AST, ALT) and cardiac indexes (CK, CKMB, LDH), and also were positively correlated with the severity of the disease index of the PSI and APACHEII scores. ROC analysis on prediction of the mortality showed that when the cutoff value of D-dimer was 3943 ug/L FEU, the area under the curve (AUC) of the D-dimer was 0.811, the sensitivity was 81.6%, the specificity was 73.8%, which was better than HsCRP and PCT. Patients with plasma D-dimer levels above 3943 ug/L FEU had significantly higher mortality compared with patients with levels below 3943 ug/L FEU (P=0.024).ConclusionPlasma D-dimer levels of H7N9 infected patients were positivily correlated with the levels of PCT, HsCRP, serum aminotransferase and myocardial enzymes. Plasma D-dimer levels were correlated with the severity and prognosis of H7N9, the higher level of plasma D-dimer, the more serious and the higher mortality of H7N9. It was helpful for clinicians to judge the severity and prognosis of H7N9 infected patients by monitoring the levels of plasma D-dimer.