Phq-9 diagnostic accuracy and optimal cut-off for depression Among patients with stroke in Nigeria

Abstract

Background: Depression is one of the most common and devastating consequences among stroke survivors. In spite of the availability of treatment for depression, the non- or under-detection precludes patients from benefiting from it.
Objectives: This study sought to validate the Patient Health Questionnaire (PHQ- 9) as a tool for detecting depression among patients with stroke.
Methodology: A cross-sectional design comprising of adult patients diagnosed with stroke, who were attending the Neurology out-patient clinic of the University of Port Harcourt Teaching Hospital was employed in the study. The Receiver Operator Characteristics (ROC) curve and validity tests were performed using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (SCID-DSM IV) as the gold standard. The optimal PHQ-9 cut-off was determined using Youden Index. Kappa statistics was performed at p<0.05.
Results: The study had a total of 197 stroke cases with PHQ-9 and SCID-DSM IV findings. The median age was 54 years (range: 35-76 years). ROC Curve for PHQ-9 revealed an Area under the Curve (AUC) value of 0.93(95% CI: 0.88- 0.98). The optimal cut off value of six was obtained based on Youden Index. Sensitivity, specificity, positive predictive and negative predictive values at the optimal cut-off were 88.7%, 93.1%, 82.5% and 95.7% respectively. The Kappa statistics yielded 0.80 (95% CI: 0.68-0.86).
Conclusion: PHQ-9 is a useful screening tool for identifying depression among patients with stroke. An optimal cut-off score of six for PHQ-9 should be adopted for patients with stroke in Nigeria to identify depression, and the provision of holistic care.