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Measure  –  Consumption


Here you find guidance, methods and tools to measure antibiotic consumption in humans, focusing on healthcare and community settings.

Information on antibiotic consumption can be used to evaluate effects of interventions, monitor consumption patterns over time, compare consumption between facilities, pharmacies or regions, or to gain insight into the various channels through which people in communities obtain antibiotics. Antibiotics may have been prescribed or dispensed in a health care facility or purchased at a pharmacy or drug outlet or street vendor.

Antibiotic consumption in health care settings

Data on antibiotic consumption and prescription patterns can be gathered from for example:

  • The Ministry of Health
  • Wholesalers drug records
  • Hospital medical stores
  • Pharmacy sales records, pharmacy stock and dispensing logs
  • Patient medical records

Antibiotic prescribing data can be extracted from outpatient and inpatient prescription forms. This process can be facilitated through the use of computerized records, but in the absence of electronic databases, relevant prescribing data can be manually extracted from patient records or retrieved at dispensing points.

Combining interviews with lab tests to understand use in Ghana:

In Ghana, data on the quantities of antibiotics sold are difficult to obtain due to weak systems for regulations of medicines. An investigation on the use of antibiotics was conducted by interviewing patients, asking if they had used antibiotics, and then comparing their answers to the prevalence of antimicrobials measured in their urine. Of the 121 urine samples analyzed, antibiotics were detected in 77. However, only 16 of these patients had responded that they had taken antibiotics. 

In Ghana, literacy rates are low and participants may have had difficulties identifying drugs they used as antibiotics. However the patients may have also unknowingly been exposed. Self-medication is often practiced in Ghana, including treatment with traditional herbal medicines, which are frequently laced with antibiotics and could account for the results.  

Point prevalence studies

Point prevalence studies are a way to collect data at a specific point or period of time. The point of time can be a single day or continuously during a period of time. The Global PPS project  provides protocols and materials for point prevalence surveys on antibiotic use globally, that can be used either directly or as a starting point when developing own protocols (see resource table below).

Antibiotic consumption in the community

Sources for measuring antibiotic consumption in the community include for example:

  • Invoices
  • Stock or dispensing records
  • Patient medical records
  • Observational studies
  • Surveys or exit interviews at pharmacies or other drug outlets

Actual consumption can be assessed by counting leftover pills or performing household surveys.

Interviews as a tool to measure antibiotic use in the community

Patients and consumers can be interviewed when leaving health care facilities, pharmacies and other dispensaries about the services, treatment recommendations, or information they received regarding antibiotics. Consumers can also be interviewed in their home, where they are likely to consume the antibiotics purchased. Examples of topics that a questionnaire could include are :

  • Types of antibiotics available/ being purchased
  • Medical problem for which antibiotics are purchased
  • Prices of the antibiotics
  • Source of advice on the purchase
  • Treatment taken before buying antibiotics
  • Ideas about the correct use of antibiotics

Interviews provide insight into antibiotic use

A study in Egypt measured antibiotic consumption by interviewing pharmacists, sale representatives and customers during one day in different local pharmacies and non-pharmacy outlets. Another example is from Vietnam, where exit interviews were used for measuring antibiotics purchased by customers.

Classification of medicines

The Anatomical Therapeutic Chemical (ATC) classification system, coordinated by the WHO Collaborating Center for Drug Statistics Methodology, is the most widely used classification system for drugs in humans. The ATC divides drugs into different groups according to the organ or system on which they act and/or their different characteristics. Most drugs are also assigned a Defined Daily Dose (DDD), the assumed average maintenance dose per day for a drug used for its main indication in adults. Use of the ATC/DDD system allows standardization of drug groupings and a stable drug utilization metric to enable comparisons of drug use and to examine trends in drug use over time and in different settings.

Understanding data on antibiotic consumption

Consumption is often converted to defined daily doses (DDD) per 1,000 inhabitants per day. In hospital settings consumption is often presented as DDDs/100 bed-days

Example for converting consumption data into DDD/1000 inhabitants/year for comparison:

Obtain the quantity of antibiotics consumed/procured within the time frame of interest. In the example below we will use one year.

  • Note the number of units e.g. (tablet, capsules or injections) and the strength.
    • Example: gram (g)/milligram(mg)
  • Multiply the number of units by the strength of the dose to obtain the total quantity.
    • Example: 80,0000 tablets of Cefuroxime*500 mg=40,000,000 mg=40,000g
  • Divide the total quantity by the DDD of Cefuroxime (DDD for cefuroxime = 0.5g).
    • Example: 40,000/0.5=80,000 DDD
  • Divide the total quantity by the population. Example Dormaa Ahenkro in Ghana with a population of 100,000 inhabitants).
    • Example: 80,000/100000 inhabitants=0.8 DDD/inhabitant/year
  • Convert to 1000 inhabitants per year.
    • Example: 0.8DDD*1000=800 DDD/1000 inhabitants/year
  • You may convert this to 1000 inhabitants/day by dividing by 365 days

See also related sections on Appropriate use and Knowledge and practices.

Resources below have been divided into the following tables:

  • Health care setting
  • Community setting
  • Databases and reports

One Health resources are found in Consumption.

Selected Resources

Health care setting

Resource Description
Methodology including data collection forms for performing point prevalence surveys on antibiotic consumption in hospitals. Adapted to LMIC settings, building on the methodologies by ECDC and others.
Global Point Prevalence Survey on Antimicrobial Consumption and Resistance Survey protocol and support. This open to join initiative allows participating hospitals to monitor antimicrobial prescribing and resistance in patients through a “one day survey” and helps design hospital interventions to promote prudent use (provides a personalized report). Hospitals are welcome to join survey and network (already more than 300 institutions from over 50 countries have participated). For documents such as protocols and data collection templates in different languages (incl. Spanish, French and Arabic) click here. Numerous scientific publications with results from the project have been published.
Protocol that provides methodology and data collection forms for performing point prevalence survey (PPS) of antimicrobial use in European hospitals. PPS survey validation protocol can be found here.
Protocol that provides methodology and data collection forms for point prevalence survey (PPS) of antimicrobial use in European long-term care facilities. PPS survey validation protocol can be found here.
AMC Tool: the antimicrobial consumption tool Tool. Computer tool for transforming antimicrobial consumption data from hospitals and the community to meaningful utilization rates (Defined Daily Doses (DDD) using the ATC/DDD index), also contains a user manual.
How to Investigate Antimicrobial Use in Hospitals: Selected Indicators Manual that defines indicators to help assess the management and use of antibiotics in hospitals and provides tools and step-by-step instructions for designing and carrying out assessment activities. Also available in French and Spanish.
Measuring antibiotic availability and use in 20 low- and middle-income countries Journal article describing how external surveys of health facilities could be used to determine general availability and use of antibiotics. Particularly focusing on key antibiotics included in the WHO’s AWaRe classifications of antibiotics.
The Worldwide Antibiotic Resistance and Prescribing in European Children (ARPEC) point prevalence survey: developing hospital-quality indicators of antibiotic prescribing for children Manual. Development of quality indicators of improved antimicrobial prescribing focusing specifically on hospitalized neonates and children worldwide. More information about the method can be found here.
GLASS methodology for a global programme on surveillance of antimicrobial consumption (PDF, 1MB) Methodology. WHO methodology describing surveillance of antimicrobial comsumption; How to collect data, what data to collect and how to manage data.
Survey protocol in nationwide hospital point-prevalence surveys in Sweden, 2003-2010 Protocol/Template. The data collection form for a nationwide point-prevalence survey performed in Sweden during 2003-2010. The results were published in Eurosurveillance: Repeated nationwide point-prevalence surveys of antimicrobial use in Swedish hospitals: data for actions 2003–2010  .

Community setting

Resource Description
The ‘Drug Bag’ method: lessons from anthropological studies of antibiotic use in Africa and South-East Asia Journal article presenting a non-verbal method for surveying antibiotic use in households and at farms. Investigates whether or not participants recognize pre-purchased antibiotics available in the study area. Participants are asked to sort antibiotics, for example based on frequency of use. The method was tried-out in studies in Zimbabwe, Malawi, Myanmar and Uganda. A drug bag questionnaire data collection form is available for download here (PDF, 0.3 MB).
How to Investigate the Use of Medicines by Consumers Manual that provides a practical guide to the methods that can be used to investigate the use of medicines by consumers to identify problems, design interventions, and measure changes.
Community-Based Surveillance
of Antimicrobial Use and Resistance in Resource-Constrained Settings
Report on five pilot projects
Report on activities associated with the implementation of five pilot projects for community‐based monitoring of antibacterial medicine use and antimicrobial resistance in resource‐constrained settings. Chapters 2 to 6 contain the reports on each of the pilot sites, giving details of the methods used, the results obtained, and commentary on the problems encountered at each site.
WEPI – Web questionnaires for epidemiologists and health professionals Questionnaire template: A web based questionnaire tool for epidemiologists and health care personnel that can be used for surveys or interviews. The system allows for unlimited amount of questions and the web page also contains a practical video on how the tool can be used.
AMC Tool: the antimicrobial consumption tool Tool. Computer tool for transforming antimicrobial consumption data from the community to meaningful utilization rates (Defined Daily Doses (DDD) using the ATC/DDD index), also contains a user manual.
Antimicrobial Resistance Module for Population-Based Survey (PDF) Manual. This module generates household-level information on knowledge and behavior regarding antimicrobial medicines and raises awareness regarding resistance among communities.

Databases and reports

Resource Description
WHO Report on Surveillance of Antibiotic Consumption – 2016 – 2018 Early implementation Report from WHO presenting data from 2015 on the consumption of systemic antibiotics from 65 countries and areas. It describes the WHO methodology for data collection, including challenges and future steps in monitoring antimicrobial consumption.
Antimicrobial Medicines Consumption (AMC) Network. AMC data 2011–2014 (2017) Report presenting and analysing data on antimicrobial medicines consumption collected from non-European Union countries in the WHO European Region and Kosovo. It aims to support countries that are building or strengthening their national surveillance systems on AMC and to stimulate the sharing of data both within and between countries.
Resistance Map Database. ResistanceMap provides interactive charts and maps summarizing national and sub-national data on antimicrobial use and resistance around the world.
Antimicrobial consumption interactive database (ESAC-Net) Database and reports. The European Surveillance of Antimicrobial Consumption Network (ESAC-Net) interactive database provides European reference data on antimicrobial consumption, both in the primary care sector and the hospital sector. ESAC-Next yearly reports (starting from 2010) can be accessed here.
Global antibiotic consumption and usage in humans, 2000–18: a spatial modelling study Journal article presenting the first longitudinal antibiotic consumption estimates in both high-income and low-and-middle-income countries including a total of 204 countries from 2000 to 2018. This research utilized data from IQVIA MIDASTM database, European Center for Disease Control, World Health Organization, Demographic Health Surveys, Multiple Indicator Cluster Survey, and published literature.

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