Analysis of the cost-effectiveness relationship in the empirical treatment in patients with infections of the lower respiratory tract acquired in the community]

Cost of treatment of community-acquired infections in Spain is an important factor in overall health expenditures. The aim of this study was to assess the direct health costs related with the treatment of patients with community-acquired pneumonia (CAP) and acute exacerbations of chronic bronchitis (AECB) due to infection, using different antibiotic options, and to identify main cost drivers.A basic decision analysis model was developed, including probabilities estimation derived from the literature review, supplemented when needed by the opinion of a panel of 8 Spanish physicians (Delphi technique). Four groups of antibiotics were included (macrolides, beta-lactam, fluoroquinolones and cephalosporins) in two different groups: patients with CAP without hospital admission criteria and patients with AECB due to respiratory infection. The analytic horizon and the perspective used were those of the Spanish National Health Service. Direct cost were assessed (drugs, outpatient visits, hospital admissions, diagnostic tests). Indirect cost were not included in the model. Final costs uses as main outcome measure the average cost per patient treated. All results were calculated following a fold-back technique. Sensitivity analysis were included allowing for variations in several clinically relevant parameters.1. Patients with CAP: Hospital admissions, directly related to the effectiveness rate of initial empirical antibiotic therapy, were the main cost driver (50%-70%). Acquisition costs of initial antibiotic therapy only account for 2%-13% of total costs. 2. Patients with AECB: Outpatient visits are the main cost driver for these group of patients (49% of total costs). Hospital admission costs are also an important cost driver (40%-51% of total costs). Acquisition costs of initial antibiotic therapy account for 4%-28% of total costs. Clinical effectiveness of first antibiotic option is the main variable regarding the cost-effectiveness rate.The model here presented showed that acquisition costs of first empirical antibiotic therapy are only a small proportion of total costs related with the management of community acquired lower respiratory tract infections in Spain. The clinical effectiveness rate of the first antibiotic used is the main variable which determines the final average cost per patient cured. For patients with lower respiratory tract infections the therapeutic option with a better cost-effectiveness ratio must be chosen, in order to minimize the risk of therapeutic failure after first line therapy, and should not be selected only by its lower acquisition costs.