Since 2019, Santé publique France has been publishing two indicators of antibiotic use in the outpatient sector based on data from the National Health System (SNDS), generated by the National Health Insurance Fund: health insurance reimbursements:

• Antibiotic consumption expressed in defined daily doses (DDD)

• The number of antibiotic prescriptions

Until 2018, national surveillance of antibiotic use in the outpatient sector relied on a single indicator: the number of defined daily doses (DDD) per 1,000 inhabitants per day. This indicator measures the “pressure” of antibiotics as a factor in the emergence of antibiotic resistance and is currently the only one used for international comparisons. It was available exclusively at the national level and compiled by the ANSM using sales data reported by manufacturers.

Two additional indicators targeting residents in nursing homes without an in-house pharmacy (PUI)

SNDS data pertain to reimbursements for prescriptions of systemic antibiotics (coded J01 according to the ATC classification) dispensed in community pharmacies, regardless of the prescriber’s practice setting. They include hospital prescriptions dispensed by community pharmacies, as well as prescriptions for patients residing in nursing homes when the facility does not have an in-house pharmacy.
For the first time in 2021, data concerning residents in nursing homes without an in-house pharmacy were extracted and are presented separately for the period 2015–2022.

Thus, two specific indicators were calculated and reported per 1,000 days of care:

• consumption expressed in defined daily doses (DDD), expressed as DDD/1,000 resident-days,

• the number of antibiotic prescriptions, expressed as Presc. / 1,000 resident-days.

They are stratified by age group, gender, class of active substances, and region.

Antibiotic prescriptions expressed per year

Since 2019, Santé Publique France has published, in addition to the standard indicator expressed in terms of daily defined doses (DDJ), an indicator expressed in terms of the number of prescriptions. This indicator provides a more direct view of medical practices and their evolution, and aids in interpreting the information provided by the number of DDJ.

Since 2021, the number of prescriptions has been reported per 1,000 inhabitants per year. Indeed, the 2022–2025 national strategy for infection prevention and antibiotic resistance uses a prescription indicator calculated annually. Furthermore, the few prescription indicators available internationally are more frequently calculated per 1,000 inhabitants per year than per day. This is particularly the case in Denmark, Sweden, and the United States.

A detailed analysis of antibiotic use in outpatient settings and its trends

The two indicators published by Santé publique France (DDJ and prescriptions) were produced for each year over the period from 2009 to 2022. They are broken down by antibiotic class, by geographic area (region and department), by age group (8 in total), by gender, and by prescriber specialty. They complement the indicators already produced by the ANSM by providing information that enables:

• a regional breakdown of national initiatives promoting the appropriate use of antibiotics;

• better identification of target populations;

• a better understanding of medical practices and how they are evolving.

Indicators accessible to all

Making these indicators available allows for better monitoring and understanding of trends in antibiotic consumption in France. On November 18, Santé publique France will publish them on its website in the form of reports and via the Géodes platform, which allows them to be viewed interactively and by region.

The data from the SNDS used by Santé publique France to produce these indicators pertain to reimbursements for prescriptions of systemic antibiotics (ATC code J01) dispensed in community pharmacies, regardless of their origin; it therefore includes hospital prescriptions when these are dispensed by community pharmacies, as well as prescriptions for patients residing in long-term care facilities (Ehpad), when the facility does not have an in-house pharmacy (PUI). These reimbursement data are used as a proxy for French consumption, assuming, on the one hand, that all prescriptions result in reimbursement, and on the other hand, that all medications reimbursed by the national health insurance system were consumed by the patients in question. These data include most insurance plans and cover 97% of the French population for the period studied.

How is antibiotic use measured?

The DDJ

The Health Insurance program counts the number of antibiotic packages reimbursed. Each package—or dosage form—is characterized by a dosage, a pharmaceutical form, and a quantity (number of doses). Converted into quantities of active ingredient, these are then divided by a “defined daily dose” (DDD) established by the WHO. The DDD serves as a reference dosage for a 70-kilogram adult in the primary indication for each antibiotic, providing an indicator of the number of DDDs associated with these prescriptions. Note that the ADR does not necessarily reflect the dosage recommended by the marketing authorization (MA) or the actual dosage: it is merely a benchmark that allows for comparisons. By convention, the results are expressed per 1,000 inhabitants per day.

To ensure consistent data series, the results presented for the years 2009 through 2022 were all calculated based on the WHO ADDs in effect as of January 1, 2023. Certain changes to the ADDs occurred between 2018 and 2019, resulting in:

1. a significant decrease in total consumption, due to the increase in the ADI for certain widely used antibiotics;

2. a shift in the distribution of consumption across major antibiotic classes.

In the absence of pediatric ADIs, it is important to note that it is not possible to directly compare consumption levels between children and adults; consumption among children is in fact underestimated since it is calculated based on an ADI for adults.

Prescriptions

This indicator is based on the total number of antibiotics prescribed during the period in question. Unlike the indicator described above, it does not take into account the amount of active ingredient dispensed. If two antibiotics are prescribed on the same prescription, two prescriptions are counted, but they correspond to a single course of treatment.