Patient characteristics and health care burden during the influenza A (H1N1) 2009 pandemic in the university Hospital Vall d'Hebron of Barcelona

Background and objective: The influenza A (H1N1) 2009 pandemic initially had a mild impact in Catalonian hospitals, but in the autumn there was an important pandemic wave. We describe the main characteristics of patients seen in the Vall d'Hebron University Hospital in Barcelona (HUVH) during this pandemic, the risk factors associated with hospitalization and the health-care burden generated. Material and method: We included all cases of influenza A (H1N1) 2009 with laboratory confirmation seen in the HUVH from July 2, 2009 to January 22, 2010. We performed a descriptive analysis of the cases and a multivariate analysis to identify variables associated with the risk of hospitalization. Results: The diagnosis was confirmed in 741 patients; 56.8% were under 16 years, while only 2.8% were 65 and over. Thirty three per cent of children had no risk factor for complications, whereas in adults it was 45%. One hundred and ninety cases were hospitalized, 26 of them in the intensive care unit (ICU) with 5 deaths. The factors associated with risk of hospitalization were, age less than one year, immunodeficiency, and neuromuscular disease in children; and chronic lung disease in adults. The diagnosis of pneumonia in the emergency department was an important predictor of hospitalization in both children and adults. The maximum caseload was recorded on November 19, with 43 hospital admissions, 6 of them in the ICU. Conclusions: Between July and September 2009 the pandemic had a low impact on hospital resources, but in autumn there was a marked increase in emergency department visits and hospitalizations. Children had higher rates of confirmed cases, while adults had higher rates of hospitalizations. The risk of hospitalization was higher in patients with certain conditions especially in those with pneumonia. The pandemic wave was a moderate work load for HUVH, since it did not involve any modification of the usual health care programs.