No drug prescription guidelines for severe obesity (BMI>35 kg/m2) are available, leading to non-standardized and / or potentially inappropriate drug management.

After validation of guidelines by the Delphi method, the main objective is to assess the agreement between the drug prescriptions and the guidelines after implementation in two health data warehouses.

The investigators will perform a retrospective, multicentric study in 2 hospitals. The investigators will check the relevance of rules (alerts) derived from the recommendations identified using the Delphi method.

No drug prescription guidelines for severe obesity (BMI>35 kg/m2) are available, leading to non-standardized and / or potentially inappropriate drug management.

After validation of guidelines by the Delphi method, the main objective is to assess the agreement between the drug prescriptions and the guidelines after implementation in two health data warehouses.

The investigators will perform a retrospective, multicentric study in 2 hospitals. The investigators will check the relevance of rules (alerts) derived from the recommendations identified using the Delphi method.

The sponsor anticipate around 800 patients in the HEGP data warehouse and around 250 patients in the Rennes University Hospital data warehouse.

The main outcome will be the number of prescriptions concerned by rules, by type of recommendation, in patients with severe obesity.

Secondary outcomes will be :

1. Number of validated recommendations and their level of evidence,
2. Rate of prescriptions concerned by a computerized rule with pharmaceutical advice on the drug concerned by the rule. Sub-group analysis of this rate by type of recommendation.

The study will be conducted in 2 steps:

• Stage 1 (secondary endpoint): it consists of the final drafting of recommendations and submission to experts/analysis of feedback. This stage is scheduled to last 12 months.
• Stage 2 (primary and secondary judgment criteria): it consists of implementing the recommendations and studying the relevance of the rules. This stage is scheduled to last 8 months.

Around a hundred patients corresponding to this criteria will be extracted from the HEGP data warehouse

Inclusion Criteria:

All patients aged 18 to 65 at the time of prescription with a BMI>35 kg/m² present in the clinical data warehouse of the HEGP and CHU Rennes during the study period with at least one hospitalization of more than 24h.

Exclusion Criteria:

• Patients who refused to have their records processed electronically.
• Patients with a history of bariatric surgery (sleeve gastrectomy, gastric band, gastric bypass) prior to hospitalization.

All patients aged 18 to 65 at the time of prescription with a BMI>35 kg/m² present in the clinical data warehouse

Individual participant data (IPD) that underlie results in publication could be shared. Data dictionary would be transmitted.

two years after the last publication

Data sharing must be accepted by the sponsor and the PI based on a scientific project and scientific involvement of the PI team.

Teams wishing obtain IPD must meet the sponsor and IP team to present scientific (and commercial) purpose, IPD needed, format of data transmission, and timeframe. Technical feasibility and financial support will be discussed before mandatory contractual agreement.

Processing of shared data must comply with European General Data Protection Regulation (GDPR).