Background: The goal of this study was to characterize the burden of anxiety among residual depressive symptoms in naturalistic primary care settings.
Methods: A post-hoc analysis of a database comprised of naturalistically treated depressed patients across Canada was done. This bilingual (English and French), multi-center, randomized validation study was conducted in 47 primary care settings in four provinces of Canada. Patients who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text-Revision (DSM-IV-TR) criteria for a major depressive episode, in the context of a major depressive disorder (N=454) were enrolled. Eligible patients received open-label, flexible-dose antidepressant treatment. The analysis reported here was limited to patients whose depression severity was evaluated using the Hamilton Depression Rating Scale (HAMD-17) (n=205). Patients completing 8 weeks of open-label antidepressant treatment (n=157) were considered evaluable. As a proxy for anxiety symptoms, scores on 6 items from the HAMD-17 (psychological anxiety, somatic anxiety, gastrointestinal distress, fatigue, hypochondriasis, and insight into illness) were summed to arrive at a composite anxiety score, which was then used to calculate an anxiety ratio (with the composite anxiety score as the numerator and the total HAMD-17 score as the denominator).
Results: The composite anxiety ratio at baseline did not correlate with the probability of remitting at endpoint (p=0.534). After 8 weeks of antidepressant therapy, remitting patients evinced a statistically significant decrease in anxiety ratio (p=0.041). Moreover, an inverse correlation was noted between severity of anxious symptoms at endpoint and probability of remission (p=0.026). The burden of anxiety, presented as the anxiety ratio, was higher in non-remitting patients at endpoint (p=0.828).
Conclusion: Residual depressive symptoms represent ongoing illness activity in depression. Sharpening the focus of therapeutic interventions in the clinical environment calls for tracking and managing residual anxiety symptoms.