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How is the consumption of antibiotics measured?

Calculation of the antibiotic consumption

The World Health Organization Collaborating Center for Drug Statistics Methodology defined the DDD (defined daily dose, DDD) as the assumed mean daily maintenance dose for a main indication of a drug in adults [1]. The DDD does not correspond to a recommended or actually prescribed daily dose, but to a technical unit of measure and comparison which has been assigned to each antibiotic.

Prescribed quantities of antibiotics are converted from grams into DDD and then reported for the inpatient sector as DDD per 100 days of care or as DDD per 1000 inhabitants per day (consumption density) for the outpatient sector respectively. This procedure is recommended by the WHO for comparative antibiotic consumption studies [2, 3, 4]. The number of inpatient days is defined by the Federal Statistical Office as the yearly sum of days on which patients stay in the stationary care.

  • [1] World Health Organization Collaboration Center for Drug Statistics Methodology. ATC index with DDDs. Oslo : World Health Organization, 2005.
  • [2] Dukes MN. Drug utilization studies. Methods and uses. WHO Reg Publ Eur Ser. 1993 ; 45 :1-4.
  • [3] European Centre for Disease Prevention and Control. Antimicrobial consumption. In: ECDC. Annual Epidemiological Report for 2016. Downloadable tables. Stockholm: ECDC; 2018. Available from: European Centre for Disease Prevention and Control – Antimicrobial consumption – Annual Epidemiological Report for 2016
  • [4] de With K, Maier L, Steib-Bauert M, Kern P, Kern WV. Trends in antibiotic use at a university hospital: defined or prescribed daily dose? Patient days or admissions as denominator? Infection. 2006; 34(2): 91-4.
Collection of Data

Human Medicine Inpatient

ANRESIS has set up a voluntary monitoring network for Swiss acute hospitals. Their hospital pharmacies send quantitative data to ANRESIS, both as total and stratified by the intensive care units, paediatrics and rarely by other specialised departments. The swiss monitoring system covers around 70 hospitals, corresponding to a coverage of around 70% of all acute hospitals. Special clinics, such as psychiatric clinics or rehabilitation/geriatric clinics, are not part of the monitoring network.

Human Medicine Outpatient

Antibiotic consumption of outpatient sector is monitored using two data sources: (i) IQVIA™, a private market research company, provides a data set on antibiotic consumption of the entire outpatient sector of Switzerland, (ii) PharmaSuisse provides data based on antibiotic prescriptions at the individual level from privately run pharmacies. The coverage corresponds to approximately 65% of all pharmacies in Switzerland.

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