The limited screening accuracy of the Patient Health Questionnaire-2 in detecting depression among perinatal women in Italy

Background: The PHQ-2 was recently recommended by the International Consortium for Health Outcomes Measurement as a form of initial perinatal screening, followed by the EPDS only for women with positive PHQ-2 score. However, the accuracy of the PHQ-2 in perinatal clinical practice has been barely researched, to date. In the present study, we aim to assess the accuracy of the PHQ-2 against the EPDS in a large sample of perinatal women. Methods: A total of 1155 consecutive women attending eleven primary or secondary health care centres throughout Italy completed the EPDS and the PHQ-2 during pregnancy (27-40-weeks) or postpartum (1-13-weeks). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio, negative likelihood ratio, post-test probabilities and area under the curve (AUC) of the PHQ-2, using a cut-off of ≥ 3, were calculated. Main findings: During pregnancy, PHQ-2 revealed low sensitivity (39.5%) and PPV (39.4%) but high specificity and NPV (97.5%). In postpartum, it revealed very low sensitivity (32.7%) and moderately high NPV (80.9%), but high specificity (99.3%) and PPV (94.4%). Given the low sensitivity despite the high specificity, the PHQ-2 demonstrated poor accuracy (AUC from 0.66 to 0.68). Conclusion: Initial screening by means of PHQ-2 failed to identify an acceptable number of perinatal women at-risk of depression in Italian clinical practice. The PHQ-2 performance suggested that it has insufficient sensitivity and discriminatory power, and may be inadequate as a screening tool for maternal depression.