Predictors of Duloxetine Treatment Persistence for Patients with Major Depressive Disorder

Objectives

Early discontinuation of antidepressant therapy is associated with relapse and increased costs. This exploratory study examined demographical and pretreatment clinical predictors of duloxetine (Eli Lilly and Company, Indianapolis, IN) treatment persistence in patients treated in real-world clinical settings.

Study Design

Using a large US managed-care claims database (PharMetrics Integrated Outcomes Database; PharMetrics Inc., Watertown, MA), study subjects were individuals aged 18 to 64 years who initiated duloxetine treatment between April 2005 and March 2006, had ≥1 claim associated with major depressive disorder diagnosis, and had continuous insurance coverage 6 months before and 12 months after initiation of duloxetine therapy. Treatment persistence was defined as continuous duloxetine treatment without a 30-day gap for ≥3 months. Chi-squared tests and logistic regression analysis were used to examine predictors of persistence.

Results

Among 9148 patients (74.1% female; mean age 45.6 years) who initiated duloxetine treatment, 63.5% stayed on the medication for ≥3 months. Logistic regression analysis showed that an initial dose ≥60 mg (odds ratio [OR] 1.43), older age groups (OR ≥1.49), and venlafaxine XR (OR 1.85) or selective serotonin reuptake inhibitor (OR 1.59) use in the prior 6 months were significantly associated with increased odds of treatment persistence, whereas prior benzodiazepine use (OR 0.86), comorbid alcohol dependence (OR 0.75), drug dependence (OR 0.76), and Parkinson disease (OR 0.36) were associated with decreased odds of treatment persistence. Findings were essentially unchanged with classification and regression tree analysis.

Conclusion

The results suggest that multiple demographic and clinical variables are associated with treatment persistence of duloxetine therapy. The findings may have important implications for clinicians to take actions to prevent early therapy discontinuation.