Retrospective study of risk factors of mortality in human avian influenza A(H7N9)cases in Hangzhou / 中华传染病杂志

ABSTRACT

Objective To investigate the risk factors related to mortality in human avian influenza A (H7N9)cases in Hangzhou.Methods The clinical and epidemiological data of 61 H7N9 patients whose diagnoses were confirmed by laboratory tests between 1st March,2013 and 2nd March,2014 in Hangzhou were collected.Descriptive analysis and univariate analysis were used to analyze the demographic,clinical and epidemiological characteristics and treatment outcomes.Patients were classified into improvement group and death group according to treatment outcomes,and risk factors for death were explored.Chi square test and t test were used for statistical analysis.Results A total of 61 patients were included in this study,among which 20(32.8%)patients died.The ratio of men to women for death attributed to H7N9 infection was three to one.The mean age of patients in death group was (63.6 ±3.8)years,which was older than that in improvement group ([55 .4±2.2]years,t =1 .97,P =0.05 ).The univariate analysis showed that the risk factors of mortality included over 60 years (χ2 =5 .16,P =0.02;OR =3.65 ,95 %CI1 .19-11 .13 ),low education level (χ2 = 5 .42,P =0.02;OR =4.20,95 %CI1 .24 - 14.00 ), chronic diseases (χ2 =4.67,P =0.03;OR=3.81 ,95 %CI1 .12-12.69),bad hand hygiene (χ2 =4.05 , P =0.04;OR=4.67,95 %CI1 .04 -11 .56 ),C-reactive protein (CRP)≥120 mg/L (χ2 =4.04,P =0.04;OR=6.00,95 %CI1 .04-35 .33),increased initial neutrophil count (χ2 =3.90,P =0.05 ;OR=4.58,95 %CI1 .01 -34.22)and decreased initial lymphocyte count (χ2 =7.12,P =0.01 ;OR =7.53, 95 %CI1 .63 - 24.51 ).Conclusion Over 60 years,low education level,chronic diseases,bad hand hygiene,CRP≥ 120 mg/L,increased initial neutrophil count and decreased initial lymphocyte count are identified as risk factors for death in H7N9 cases in Hangzhou.