[Use of services and costs in patients with influenza (H1N1) 2009 in Spain: background and research protocol].

Influenza epidemics cause not only both morbidity and mortality but also have a great socio-economic impact. Occasionally, influenza infections become pandemics, such as the case of the last influenza (H1N1) 2009 virus outbreak. Taking into account the current available evidence, and being the flu syndrome a main cause of epidemiologic impact of maximum relevance for health services managers, the evaluation of health and social resources use and its associated costs should be a priority. With the objective of addressing that need, this study was set in motion. Its research protocol is presented in this manuscript. It is an observational, longitudinal and multicentric study, that aims to compare the sanitary costs with those derived from loss of productivity; as well as to estimate the incremental costs and cost-utility of prevention and treatments interventions; in both hospitalized and outpatients. Socio-demographic and clinical variables, use of resources and health status of patients will be collected (baseline and follow-up evaluations). Analyses will be conducted from the society prospective, and incidence approach. Unitary costs will be imputed to the use frequency for the monetary assessment. Incremental costs of prevention strategies and treatments will also be calculated. Cost-utility will be estimated from the loss of utility; and also loss of quality-adjusted life years will be analyzed. Our study will contribute with original information for estimating the economic impact of flu, and help health management decision making.