Validity and Performance of the Patient Health Questionnaire (PHQ-2) for Screening of Depression in a Rural Chilean Cohort.

Validity of PHQ-2 to screen for depression was assessed in an agricultural population in Chile. The sample included 4767 adults enrolled from 2014 to 2017 in a population-based cohort of chronic disease in Maule, Chile. Receiver operating characteristic (ROC) curve analysis was used to find the optimal PHQ-2 cut-off for depression, defined as the highest Youden index, using PHQ-9 as a reference standard. Sensitivity, specificity, and Youden J index were calculated for every cut-off point of PHQ-2. Prevalence of depression measured by PHQ-9 and PHQ-2 was 18% and 18.4%, respectively. Corresponding rates for women were 24.7% and 23.6%, and 8.3% and 10.9 for men. The optimal PHQ-2 cut-off score was 3, achieved with a sensitivity of 74.6%, specificity 93.9%, and Youden index of 0.68. The area under the curve for the ROC analysis ROC curve was 0.92 (95% CI 0.91-0.93). PHQ-2 has good performance for use as a test for depression screening in a rural population of Chile and can be easily applied in areas with low resources.