European Surveillance of Antimicrobial Consumption (ESAC): Data Collection Performance and Methodological Approach

Abstract

Background Europe is a continent with strong public healthcare systems, but diverging antibiotic policies and resistance patterns. Aims To describe the performance and methodological approach in a retrospective data collection effort (1997–2001), through an international network of surveillance systems, aiming to collect publicly available, comparable and reliable data on antibiotic use in Europe. Methods A central multidisciplinary management team co‐ordinated a network of national representatives, liasing with national data providers and bodies responsible for antibiotic policy. The data collected were screened for bias, using a checklist. We focused on detection bias in sample and census data; errors in assigning medicinal product packages to the Anatomical Therapeutic Chemical Classification (ATC); errors in calculations of defined daily doses (DDD) per package; bias by over‐the‐counter sales and parallel trade; and bias in ambulatory care (AC)/hospital care (HC) mix. Datasets were corrected after national feedback, and classified as valid; valid but with minor bias; not valid. Results Of the 31 participating countries, 21 countries delivered AC data suitable for cross‐national comparison (14 for all 5 years). Of these, 17 countries provided data on a quarterly basis for at least 1 year. For HC, 14 countries were able to deliver valid data (nine for all 5 years). A valid estimate of the total exposure of national populations to human antibiotic consumption could be made in 17 countries. Conclusion In cross‐national comparisons of antibiotic consumption in Europe, methodological rigour in correcting for various sources of bias and checking the validity of ATC/DDD assignment is needed.