Treatment resistant depression incidence and prevalence using the French nationwide claims database

Purpose To estimate annual incidence and prevalence of Treatment-Resistant Depression (TRD) in France. Methods We identified all adult patients (>= 18 years) with a TRD episode between 1 January 2012 and 31 December 2014 in the EGB (echantillon generaliste des beneficiaires), a permanent random sample of the French nationwide claims database. After a 6-month washout period without hospitalization for depression or any antidepressants (AD), and after exclusion of psychotic or bipolar affective disorders, Parkinson's disease and dementia, a TRD episode was defined by three successive sequences of different AD over a 3-month treatment period (6 months for a sensitive analysis), with at least 3 weeks before each sequence change and a Medication Possession Ratio >= 80%; or by the dispensing of >two different AD together; or of an AD with a potentiator (lithium, antiepileptic drugs, antipsychotic drugs, thyroid hormones) over the same treatment period. The annual incidence rate was estimated from 2012 to 2014 and the prevalence using a Gamma parametric function based on treatment duration and a 30-year prediction. Results Between 2012 and 2014, 700 patients were identified in EGB with a TRD episode. The mean age was 47.4 years (+/- 15.3); 52.7% were women. Annual incidence and prevalence of TRD were estimated at 5.8 and 25.8 per 10 000 patients, respectively and at 7.8 and 37.6 per 10 000 patients, respectively in the sensitivity analysis. Conclusion This study provides the first population-based estimates for incidence and prevalence of TRD in France.