Study On The Establishment Of Hemorrhagic Fever With Renal Syndrome (HFRS) Critical Score In Predicting The Prognosis For Patients With HFRS

Background and ObjectiveHemorrhagic fever with renal syndrome(HFRS) is an infectious disease carried by human and mice with mouse is the source of infection, characterized by fever, hypotension shock,and renal damage。Its pathogen is one of hantaviruses, with its mechanism is widely lesions of systemic small vessels and capillaries。As early diagnosis rate of HFRS in our country is low,patients of HFRS in hospital are always acute onset,with a high case fatality rate.Therefore, to predict the prognosis of HFRS in an early stage and take preventive measures timely means a lot to reduce morbidity. At present, the clinical scoring system to evaluate the prognosis of the severe disease are several, such as simplified acute physiology score(SAPSII),sepsis-related organ failure assessment(SOFA),multiple organ dysfunction syndrome(MODS) and so on.These scores analyze the development, the prognosis,the outcome of several severe diseases in the form of quantitative points assigned from different angles,which has positive clinical significance.However,as the pathophysiology and clinical process of HFRS has its own specificity, the existing evaluation methods is difficult to assess the patient accurately.In this study, we establish a critical scoring system of HFRS according to the clinical characteristics and index of clinical classification,composed by SIRS state, extravasation, plasma colloid osmotic pressure, platelet count and urinary protein,in order to assess the development and prognosis of HFRS more briefly and accurately.Methods The subjects were the patients diagnosed HFRS in our hospital from January2000to April2011. In the120enrolled cases,89were male and31were female.Their ages range from26to75years, with an average of37.617.8.They were divided into survival group (90cases) and death group (30cases) according to prognosis.The diagnostic of HFRS is consistent with standard of diagnose and classification established in the national hemorrhagic fever with renal syndrome conference inl987,meanwhile the IgM of hantaviruses is positive.Since the day when HFRS was confirmed,we has collected the clinical data from the third or the fifth day during the fever stage.The enrolled patients were divided into survival group and death group according to the prognosis during the three-month follow up.The HFRS critical score:HFRS critical score is made of SIRS state, extravasation, plasma colloid osmotic pressure, platelet count and urinary protein. Every parameter is divided into five levels according to the severity of disease, marked0、1、2、3and4points from low to high,with a highest total score up to20points.SIRS can be diagnosed when two or more of these four criteria are present.(1) Body temperature less than36℃or greater than38℃;(2) Heart rate greater than90beats per minute;(3)Tachypnoea(high respiratory rate), with greater than20breaths per minute; or, an arterial partial pressure of carbon dioxide less than4.3kPa (32mmHg);(4) White blood cell count less than4000cells/mm (4x109cells/L) or greater than12,000cells/mm (12x109cells/L); or the presence of greater than10%immature neutrophils (band forms).Plasma colloid osmotic pressure (mmHg)=albumin (g/dl)5.54+globulin(g/dl)1.43.Extravasation levels divided into mild, moderate, severe and very severe.The mild:chemosis; The moderate rchemosis+Facial edema;The severe:chemosis+Anasarca(or three effusion);The very severe:chemosis+Anasarca+t three effusion.Statistical software SPSS18.0was used for statistical analysis. Measurement data noted as x±s. T-test was used to do group differences. Compare the predictive ability of scoring method using receiver operating characteristic (ROC) area under the curve (AUC). According to the ROC curve to determine the optimal diagnostic threshold, and determine the sensitivity and specificity of the threshold, calculate Youden index.Results1.All of the five parameters of HFRS critical scores in the death group were significantly higher than those in the survival group (P<0.05). The scores of sirs, plasma colloid osmotic pressure and urinary protein in death group were higher than those in the survival group (P<0.05),while the scores of extravasation and platelet count were even more higher(P<0.01).2.The scores of HFRS critical score, SOFA score and SAPS Ⅱ score in the death group are significantly higher than those in the survival group(P<0.01).3.The area under the curve (AUC) of SOFA score, SAPS Ⅱ score and HFRS critical score are0.704,0.731and0.804respectively. The Youden index of the HFRS critical scores is the highest (P<0.01) in all three scores,followed by SAPS Ⅱ score and SOFA score.If HFRS critical score10was used as cut off value, the specificity and the sensitivity for predicting the risk of death for the patient in admit was respectively77.4%and78.8%. We compared the AUC of HFRS critical score with SAPS Ⅱ score and SOFA score respectively using normality Z test. It showed that there were significant differences between the two groups (z=13.16,P<0.05; z=29.68, P<0.01).Conclusions1.HFRS critical score with chosen parameters is consistent with the clinical pathophysiological characteristics of HFRS. Moreover, it is a easy and quick method, more targeted and practical,compared with the traditional grading.2. HFRS critical score can predict the severity and prognosis of HFRS just during the fever phases, which help clinicians to take preventive measures timely.3.If HFRS critical score10was used as cut off value, the specificity and the sensitivity for predicting the risk of death for the patient in hospital was respectively77.4%and78.8%.4. SOFA score and SAPS Ⅱ score have clinical predictive value,but the sensitivity and the specificity are lower than the HFRS critical score,it has significant statistical difference.