Factors associated with severity of Postnatal Depression and optimal cut-off of Edinburgh Postnatal Depression Scale (EPDS) for diagnosis of depression among postpartum HIV- positive women in Lusaka, Zambia

Abstract

Purpose: Postnatal depression (PND) may affect adherence to HIV treatment and thus postnatal HIV transmission. The Edinburgh Postnatal Depression Scale (EPDS), widely used to screen for PND, has not been adequately validated in HIV positive, perinatal women in Zambia. Additionally, factors associated with severity of EPDS scores are unknown.
Methods: As part of a depression treatment trial, we screened HIV positive women with the EPDS between 6-10 weeks postpartum. To identify women at the lower symptom threshold, those scoring ≥6 (out of 30) on the EPDS were referred for a diagnostic Mini International Neuropsychiatric Interview (MINI). We investigated risk factors associated with higher EPDS scores. Additionally, we estimated the optimal EPDS screening threshold for diagnosis of depression with a receiver operating characteristic (ROC) curve. Based on the literature, we defined an EPDS of 6-13 as “EPDS mild” and an EPDS ≥14 as “EPDS moderate/severe”.   

Results: 192/240 (80%) women screened scored ≥6 on the EPDS, of whom 120 (63%) agreed to undergo MINI evaluation. Of these, 61/120 (51%) scored between 6 and 13 (inclusive) and 59/120 (49%) scored ≥ 14. In unadjusted analysis, factors associated with EPDS scores ≥ 14 were not being married or living with partner (prevalence ratio [PR]=1.59; 95% CI 1.11, 2.27; p=0.01) and having more life stressors (mean difference 1.0; 95% CI 0.2, 1.8; p=0.01).  Having more life stressors remained significant in the adjusted model (aPOR 1.23; 95% CI 1.02,1.50; p=0.04), with each additional life stressor increasing odds of moderate/severe depression by 23%.  An EPDS score of ≥11 performed best at discriminating MINI-diagnosed depression with a sensitivity of 83% and a specificity of 57%.  
Conclusions: An EPDS score ≥ 11 was the optimal threshold for determining depression in HIV positive postpartum women. Women with a greater number of life stressors were more likely to score higher on the EPDS.