RESUMEN
Background: Patient Health Questionnaire (PHQ-9) has nine questions and is used in diabetic or hypertensive patients to detect depressive symptoms. The PHQ-2 uses the first two questions of the PHQ-9 to rapidly detect those patients that should answer the whole questionnaire. Aim: To validate the PHQ-2 to detect depressive symptoms in diabetic or hypertensive patients consulting at Primary Health Care (PHC). Material and Methods: Secondary analysis of data obtained during the baseline assessment of a clinical trial. Diabetic and hypertensive patients aged 18 years or more, attending a public health care clinic of Metropolitan Santiago, were invited to participate. Those accepting, answered the Patient Health Questionnaire (PHQ-9), consisting in nine questions about depressive symptoms. Demographics and health data were also collected. The PHQ-2 capacity to discriminate PHQ-9 scores equal or higher than 10 and 15 and the correlation between both versions, were assessed. Results: Ninety-four participants aged 64 ± years (73% women) answered the questionnaire. A cut-off score of 3 or more points in the PHQ-2 achieved the best tradeoff between sensitivity and specificity for discriminating PHQ-9 scores equal or higher than 10 (area under the receiver operating characteristic curve (ROC) = 0.92, 95% confidence interval [95% CI] = 0.87 to 0.97) and 15 points (area under the ROC curve = 0.95, 95% CI = 0.92 to 0.99). Both versions had a high positive correlation (r = 0.87). Conclusions: The PHQ-2 allows a stepped, simple and accurate screening for depressive symptoms. Diabetic or hypertensive patients with 3 or more points should be immediately assessed with the remaining questions of the PHQ-9.