Prognostic factors for influenza-associated hospitalization and death during an epidemic

To predict which patients with current high-risk disease in the community m ay benefit most from additional preventive or therapeutic measures for infl uenza, we determined prognostic factors for influenza-associated hospitaliz ation and death in a general practice-based case-control study among this s egment of the vaccine target population with high influenza vaccination rat es. In 103 general practices followed during the 1996/7 influenza epidemic, cases were either hospitalized or died due to influenza, bronchitis, pneum onia, diabetes, heart failure or myocardial infarction. Age- and gender-mat ched controls were randomly sampled from the remaining cohort. Information was collected by review of patient records. In total, 119 cases and 196 mat ched controls were included. Of the cases, 34, 25 and 4% were hospitalized for acute pulmonary and cardiac disease and diabetes, respectively, and 37% died. Multivariate conditional logistic regression analysis revealed that presence of chronic obstructive pulmonary disease, heart failure, previous hospitalization, high GP visiting rate and polypharmacy were independent pr ognostic factors. Several non-modifiable determinants can be used to ensure targeting additional preventive or therapeutic measures at the most vulner able segment of the vaccine target group.