Background: In Colombia, no data are available on the estimation of the cost and effectiveness of treatment for community-acquired pneumonia (CAP) managed in an ambulatory setting. Different studies have reported that the main cost of CAP is related to hospitalisations.

Objectives: To assess the cost-effectiveness of azithromycin, clarithromycin, amoxicillin-clavulanic acid, erythromycin and amoxicillin as empirical outpatient treatment options for community-acquired pneumonia without risks factors in adult patients under 65 years old in Colombia.

Methods: We designed a decision-tree cost-effectiveness model, from a third-party payer perspective (only direct medical costs, for the Colombian healthcare system) and a one-month time horizon. Total costs were estimated using official standard national sources of 2015 as well as hospital bills. Base cases were validated by an expert panel, results were converted to USD using the exchange official rate for 2015 (1 USD = 2743.39 COP, Colombian pesos). Effectiveness was defined as clinical cure, and was analysed with multivariate metanalysis based on a comprehensive literature review. Incremental cost-effectiveness ratios (ICER) were calculated, and deterministic and probabilistic sensitivity analyses were performed.

Results: Costs (and effectiveness rate) for each for each of the alternatives were, per patient treated: azithromycin $87.21, clarithromycin $203.32, amoxicillin-clavulanic acid $259.22, erythromycin $475.5, and amoxicillin $2325.06. Azithromycin dominates over the other treatments evaluated (Cost-effectiveness ratio USD $ 87,21). Results did not change significantly under the sensitivity analyses conducted.

Conclusions: Azithromycin was dominant, it can reduce the hospitalisation ratio and health system costs in Colombia. It may be the choice for outpatient treatment in subjects under 65 years-old without risk factors.