Conventional mood stabilizers and/or second-generation antipsychotic drugs in bipolar disorders: A population-based comparison of risk of treatment failure

Background: The study compared treatment failure when using three therapeutic strategies in bipolar disorders: (i) mood stabilizers (MSs: lithium, valpromide, divalproate, carbamazepine, lamotrigine) without second-generation antipsychotic (SGAP); (ii) SGAPs (aripiprazole, olanzapine, risperidone, quetiapine) without MS; (iii) combination of MSs and SGAPs.

Methods: A historical cohort study was conducted using the French national healthcare databases in 20,086 outpatients aged 21+, newly treated with one of the three treatment strategies in 2011-2012, and diagnosed with a bipolar disorder. A composite outcome was based on indicators of treatment failure identified over 12 months: treatment discontinuation, switch or addition, psychiatric hospitalisation, suicide attempt, and death. For each strategy, the cumulative incidence of treatment failure was calculated while adjusting for covariates by propensity score weighting.

Results: A total of 8,225 patients (40.9%) were newly dispensed MSs, 9,342 (46.5%) SGAPs, and 2,519 (12.5%) both MSs and SGAPs. The one-year adjusted cumulative incidence of treatment failure was 75.7% (95%CI 74.9;76.3) in patients using MSs, 75.3% (74.6;76.0) in patients using SGAPs, and 60.5% (58.3;62.6) in patients with the combination. The adjusted difference in incidence for SGAPs compared with MSs was -0.40% (-1.4;0.6 p = 0.4) in the whole population, -2.2% (-3.3; -1.2 p < 0.002) in patients under 65 years and +6.7% (4.1;9.1 p < 0.002) in patients 65 years and over.

Limitations: Combinations of MSs and SGAPs could not be directly compared with MS or SGAP monotherapies.

Conclusions: One-year treatment failure was high. Overall, no difference in treatment failure was observed between MS or SGAP strategy but differences might exist depending on age.