Relationship between the number of different antibiotics used and the total use of antibiotics in European hospitals.

Objectives: The aim of this study was to establish whether there was a relationship between the number of antibacterial agents used and total antibiotic use in European hospitals.
Methods: A total of 139 hospitals from 30 countries supplied data on antibiotic use (ATC group J01) for 2001, expressed as the number of defined daily doses per 100 occupied bed-days (DDD/100 BD) and also numbers of different antibiotics used.
Results: Participating hospitals used a median of 46 antibiotics in 2001 (range 16-82). The most frequently used antibiotic per hospital accounted for a median of 16.5% (range 7.2-60.9%) of total use and the 10 most frequently used agents accounted for a median of 73.7% (range 53.0-98.5%) of total use. Numbers of antibiotics used varied significantly by European geographical region (Kruskal-Wallis test, P = 0.001). The median total antibiotic use was 49.6 DDD/100 BD. A statistically significant relationship was found between the number of antibiotics used and total antibiotic use (Spearman's rank, r = 0.40 and P < 0.01) for all hospitals. Individual correlations were significant in Western (r = 0.57, P < 0.01) and Southern Europe (r = 0.67, P < 0.01) only.
Conclusions: The quantitative use of antibiotics in European hospitals was highly variable as was the number of different antibiotics used. In the two areas exhibiting highest total use, the greater the number of antibiotics used, the higher the total use of these drugs. Intervention studies are now needed to ascertain whether or not successful antibiotic restriction policies can reduce total antibiotic use and subsequently reduce antibiotic resistance.