Sinhala translation of the Perinatal Anxiety Screening Scale: a valid and reliable tool to detect anxiety disorders among antenatal women

BACKGROUND: Anxiety disorders during pregnancy are not routinely assessed in Sri Lanka despite being common and being associated with adverse pregnancy outcomes. Screening can facilitate early detection and management of anxiety and improve pregnancy outcomes. Our aim was to determine the validity of the Sinhala translation of the Perinatal Anxiety Screening Scale (PASS) to detect anxiety among Sri Lankan pregnant women. METHODS: A cross-sectional study was conducted in antenatal clinics of a teaching hospital in Colombo District. The PASS was translated to Sinhala using the standard translation/ back-translation method. Pregnant women (n = 221) were sequentially recruited and assessed by a psychiatrist until 81 women with anxiety disorder were diagnosed using the International Classification of Diseases-10 criteria (gold standard). The Sinhala translation of the PASS (PASS-S) was administered to all recruited women, including 140 women without anxiety. Receiver-Operating- Characteristic (ROC) analysis was performed, the optimal cut-off score for PASS-S was determined, and its validity was assessed using sensitivity, specificity, predictive values and positive and negative likelihood ratios. Internal consistency was assessed using Cronbach’s alpha. Test-retest and inter-rater reliability for PASS-S score and anxiety classification were assessed using intra class correlation coefficient (ICC) and Cohen’s kappa (k), respectively. RESULTS: The mean age (±SD) of women was 30(±5.8) years, and 53.7% were multiparous. A psychiatrist diagnosed anxiety disorder was made in 37.0% of women, while the PASS-S, at its optimal cut-off of ≥20, classified 37.5% of women as having anxiety disorders. The area under the ROC curve for the PASS-S was 0.96 (95%CI 0.94–0.99). Sensitivity, specificity and positive and negative predictive values of the PASS-S were 0.93 (95% CI 0.84–0.97), 0.90 (95% CI 0.83–0.94), 0.85 (95% CI 0.75–0.90) and 0.95 (95% CI 0.89–0.98), respectively. Positive and negative likelihood ratios were 8.8 (95% CI 5.3–14.5) and 0.08 (95%CI 0.04–0.18), respectively, and the internal consistency was high (Cronbach’s alpha 0.95). Four-factor structures obtained by exploratory factor analysis were “acute anxiety and adjustment”, “social anxiety, specific fears and trauma”, “perfectionism and control” and “general anxiety”.Test-retest reliability was high for the PASS-S score (ICC 0.85[95% CI 0.65–0.96]) and anxiety classification (k 0.77[95% CI 0.34–1.2]). Inter-interviewer reliability was also high (ICC 0.92[95% CI 0.81–0.97] for the PASS-S score and (k0.86 [95% CI 0.59–1.1] for anxiety classification). CONCLUSION: The Sinhala translation of the PASS is a valid and reliable instrument to screen for anxiety disorders among antenatal women in Sri Lanka.