Background: Depression is a leading cause of morbidity worldwide. The majority of treatment for depression occurs in primary care, but effective care remains elusive. Clinical decision making and comparative studies of real-world antidepressant effectiveness are limited by the absence of clinical measures of severity of illness and suicidality.
Methods: The Distributed Ambulatory Research in Therapeutics Network (DARTNet) was engaged to systematically collect data using the 9-item Patient Health Questionnaire (PHQ-9) at the point of care. We used electronic health records (EHRs) and the PHQ-9 to capture, describe, and compare data on both baseline severity of illness and suicidality and response and suicidality after diagnosis for depressed patients in participating DARTNet practices.
Results: EHR data were obtained for 81,028 episodes of depression (61,464 patients) from 14 clinical organizations. Over 9 months, data for 4900 PHQ-9s were collected from 2969 patients in DARTNet practices (this included 1892 PHQ-9s for 1019 adults and adolescents who had at least one depression diagnosis). Only 8.3% of episodes identified in our depression cohort had severity of illness information available in the EHR. For these episodes, considerable variation existed in both severity of illness (32.05% with no depression, 26.89% with minimal, 19.54% with mild, 12.04% with moderate, and 9.47% with severe depression) and suicidality (69.43% with a score of 0, 22.58% with a score of 1, 4.97% with a score of 2, and 3.02% with a score of 3 on item 9 of the PHQ-9). Patients with an EHR diagnosis of depression and a PHQ-9 (n = 1019) had similar severity but slightly higher suicidality levels compared with all patients for which PHQ-9 data were available. The PHQ-9 showed higher sensitivity for identifying depression response and emergent (after diagnosis) severity and suicidality; 25% to 30% of subjects had some degree of suicidal thought at some point in time according to the PHQ-9.
Conclusions: This study demonstrated the value of adding PHQ-9 data and prescription fulfillment data to EHRs to improve diagnosis and management of depression in primary care and to enable more robust comparative effectiveness research on antidepressants.