Sensitivity to change and minimal clinically important difference of Edinburgh postnatal depression scale

Edinburgh Postnatal Depression Scale (EPDS) was widely used in measuring depression symptoms among pregnant women. However, it is still unclear about the sensitivity to change and minimal clinically important difference (MCID) for EPDS.

Based on data from an eight-week smartphone-based mindfulness intervention, scores of EPDS, 9-item Patient Health Questionnaire (PHQ-9), and 7-item Generalized Anxiety Disorder (GAD-7) before and after the intervention were collected. Three self-appraisal questions were collected after the intervention. The sensitivity to change of EPDS was determined by correlations between changes in PHQ-9, GAD-7, and EPDS. MCID for EPDS was determined by distribution-based method (0.5 standard deviation and standard error of the measurement) and anchor-based method (PHQ-9, GAD-7, and participants' self-appraisal served as anchors). The final MCID value for EPDS was calculated by average scores of the two methods. 117 women with pre-post assessments were included in the analysis.

EPDS score changes from baseline to post-intervention were correlated with pre-post change in PHQ-9 and GAD-7 (r = 0.540, P < 0.001). The average MCID for EPDS score was found to be 4 points (ranging from -1.45 to -6.5 points) for improvement and 3 points for worsening (ranging from 1.45 to 3.5 points).

The EPDS is sensitive to detect the changes in maternal depressive symptoms during pregnancy through a mindfulness course of interventions. Four points for improvement and three points for worsening are recommended as MCID for EPDS.