Treatment patterns for patients with treatment resistant depression in France using nationwide claims database

Background: Prevalence of TRD varied widely across studies. Several treatment strategies exist to manage patient with Treatment-Resistant Depression (TRD) but evidence from real-world data is scarce. Investigating their use in real life is important to understand national prescribing practices and to refine prevalence estimation. Method: All adult patients (>18 years) with a TRD episode for the year 2019 were identified in a sample of four French regions accounting for 27% of national individuals. After exclusion of psychotic or bipolar affective disorders, Parkinson's disease, and dementia, a TRD episode was defined 1/ by three successive sequences of different AD, or 2/ by the dispensing of several different AD together, or 3/ by an AD with a potentiator (lithium, antiepileptic drugs, antipsychotic drugs) over the same treatment period. The prevalence rate was estimated for the year 2019 and treatment patterns were described by treatment class associations and molecules. Results: For the year 2019, 66,810 patients were identified with a TRD episode, accounting for 23.9% of all patients treated for depression. The mean age was 56 years (sd:15.9) with 63.7% of women. Standardized prevalence of TRD was estimated at 35.1 per 10 000 patients, and 25.8 per 10,000 patients when excluding patients probably treated for another primary diagnosis than depression. Association of AD and antipsychotic was the most frequently used strategy, with SSRIs and second-generation antipsychotics being most prescribed. Conclusion: In conclusion, this study provides the robust population-based estimates of the prevalence of TRD in the French population. Description of treatment patterns highlight the widespread use of second-generation antipsychotics as potentiator of AD medication complemented with anxiolytics. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was fully funded by Public Health Expertise ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was conducted from a sample of the French nationwide claims database (SNDS database) under the regulatory approval MLD/TDC/AR 211497 (CNIL reference number) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data are not publicly available