What is the most appropriate metric for the assessment of volume of antibiotic use?

One of the core elements of antibiotic stewardship is surveillance and monitoring of quantity of antibiotic use. This requires tools for measuring the quantity of antibiotic use. However, these metrics have not been standardized, and different metrics are used across different countries, regions and individual healthcare settings. In the literature, there is much controversy on the most appropriate metric for monitoring antibiotic use. Several authors have questioned the relevance of DDDs, which are recommended by the WHO, while others still prefer using DDDs as the best available metric. The results of the recent DRIVE-AB project suggest that a combination of metrics may be the best approach, since all metrics have limitations and provide different perspectives.