[Performing pharmacoepidemiological studies using the French health insurance data warehouse (SNDS): How to translate guidelines into practice]. / Réalisation d'études pharmacoépidémiologiques à partir du système national des données de santé (SNDS) : application des recommandations dans la pratique.

The French health insurance data warehouse named SNDS is one of the largest medico-administrative in the world allowing for powerful pharmacoepidemiological studies, based on real-life data collected prospectively. In addition to the absolute necessity of a strong pharmacological rationale, recommendations have been thought to improve the quality of pharmacoepidemiological studies. These guidelines emphasize the importance of an accurate definition of the study population, outcome and exposure, especially for studies performed on medico-administrative databases. Compliance with certain guidelines, particularly those concerning the identification of a specific population or an outcome and the definition of risk periods or exposure periods, may be difficult when performing studies on the SNDS because of its structure and the nature of the data recorded. The objective of this article is to provide advice for the conduct of pharmacoepidemiological studies according to the recommendationswhen using the SNDS, given its specificities. The performing of reliable studies from this rich but complex data warehouse requires the expertise of researchers with deep knowledge both in the SNDS and in pharmacological reasoning.

The value of a health insurance database to conduct pharmacoepidemiological studies in oncology.

Some concerns have emerged about the evidence of benefits on survival outcomes or quality of life of new anticancer drugs. In parallel, the decreased cancer mortality leads to an increased number of patients exposed to cancer treatment-related consequences. In this context, pharmacoepidemiology is crucial to assess anticancer drug use, effectiveness and safety in real life conditions. We aimed to describe strengths, limitations and considerations associated with the use of the French national health insurance database (système national des données de santé [SNDS]) to conduct pharmacoepidemiological studies in oncology. The SNDS represents a powerful tool in pharmacoepidemiology owing to its extensive coverage, accurate description and quantification of drug exposure and individual data on patients. The main limitations of this database ensue from the administrative nature resulting in technical difficulties in its management and gaps in availability of data. Another limitation is the lack of accurate identification of diseases, comorbidities or outcomes and potential confounding with notably the lack of data regarding cancer stage, prognosis or risk factors. Finally, the accurate identification of the nature of chemotherapy received by patients is sometimes complex. To minimize these limitations, several approaches and statistical methods could be used as highlighted by national or international initiatives. First, the SNDS may be linked with cancer registry or clinical data. Then, several data sources could be combined using meta-analytical methods. The development of methodological tools and the use of standardized methods are crucial to enhance the quality of studies that can impact clinical practice and guide public decision. Pharmacoepidemiological approaches and pharmacovigilance represent an important cornerstone in oncology for signal detection or long-term follow up of cancer patients. In this context, validated methods to identify cancer patients and to describe chemotherapy regimens within these data should be promoted and remain too scarce despite international guidelines. Moreover, limits and strength of each data sources should be systematically discussed according to the research question. Optimized and framed use of claims database represents a future challenge in onco-pharmacoepidemiology.

Is there overuse of proton pump inhibitors in B-cell non-Hodgkin lymphomas? A cohort study based on the French health insurance database in the Midi-Pyrénées region.

Patients suffering from B-cell non-Hodgkin lymphomas (B-NHL) have an increased likelihood of being exposed to proton pump inhibitors (PPIs), related to several factors which have been reported in the literature. PPIs are among the drugs most likely to be prescribed inappropriately. Consequently, B-NHL patients could be particularly at risk of inappropriate PPI prescription, with potential adverse drug reactions. We aimed to evaluate the incidence of PPIs use and to identify factors associated with PPIs initiation during the active treatment phase of B-NHL. We conducted a new-user cohort study using regional data from the French national health insurance database in the Midi-Pyrénées region (southwestern France). Incident B-NHL patients were selected according to an algorithm of selection, validated with data from a cancer registry. Our study revealed that 48.9% (95% confidence interval [CI]: 45.2-52.6) of patients initiated PPIs during chemotherapy after B-NHL diagnosis. According to information available in the SNDS, recommended indications for PPI prescriptions were identified in 21.1% of cases. Median duration of treatment was 65.3 days (CI: 35-112). Determinants of PPIs initiation were peptic ulcer disease, gastroprotection (appropriate or not) for medications considered at risk (NSAIDs, glucocorticoids and anticoagulants), age, nonfollicular lymphoma, polypharmacy, gastroenterologists' consultations and being hospitalized in a university hospital. Around 50% of patients initiated PPI treatment during the chemotherapy phase with only one-fifth identified as appropriate prescriptions and with long durations of treatment in most cases. Given this background, appropriate PPI prescription should be promoted in B-NHL to avoid potential inappropriate chronic use and related adverse events.