Clinical characteristics of severe acute respiratory infection and risk factors associated with adverse outcomes in Beijing,2014-2015 influenza season

Objective To understand the clinical characteristics of severe acute respiratory infection(SARI) and the risk factors associated with adverse outcome in SARI cases in Beijing. Methods Epidemiologic and clinical information of the SARI cases were collected from 10 sentinel hospitals in Beijing from September 2014 to April 2015,and respiratory tract specimens were collected from them for influenza virus RNA detection. Receiving ICU treatment and death were considered as adverse outcomes. Logistic regression analysis was conducted to identify the risk factors associated with adverse outcomes of the SARI cases and influenza positive SARI cases respectively. Results A total of 4230 SARI cases were found in the 10 sentinel hospitals, in which 1480 were surveyed. The data of 1315 were analyzed. The cases aged5 years and 60 years accounted for 33.76% and 31.86% of the total respectively. The median length of hospitalization of the SARI cases was 8 days. Influenza was confirmed in about 22.36%(n=294) of the SARI cases. For all the SARI cases, the risk factors associated with adverse outcomes included underlying diseases(cardiovascular disease, immune system diseases, kidney disease, diabetes). Compared with cases aged60 years,the cases aged 60 years had higher risk for adverse outcome. For the influenza cases, immune system diseases(OR=6.97, 95% CI:1.12-43.28) and kidney disease were the risk factors(OR=8.92,95% CI: 1.36-58.43) for adverse outcome. Conclusion Underlying disease and advanced age were the risk factors associated with adverse outcome in inpatients with respiratory infection.