Burns Depression Scale Today (BDST): A validation study of BDST against the reference standard of PHQ-9

BACKGROUND: Case finding for low mood is essential in primary care, but it is time-consuming using current depression inventories. The Burns Depression Scale Today (BDST) is a short, simple inventory which assesses mood for today, and we aimed to validate it in this study. MATERIALS AND METHODS: Consecutive patients with emotional distress seen in a single primary care clinic by one of the authors over 22 months were eligible for this retrospective audit (N = 160). Multiple visits (N = 421) from the same patient were included in the study. The index test was BDST, which assesses the patient’s mood for today. The reference standard was the 9-item Patient Health Questionnaire (PHQ-9), which assesses mood over the past 2 weeks. PHQ-9 had a cut-off point of ≥10 and BDST had a cut-off point of ≥6 for a significant mood issue. RESULTS: The median age of patients was 35 years, and 63% of the cohort were women. The median BDST score was 8, indicative of moderately low mood, and the median PHQ-9 score was 15, indicative of moderately severe depression. For patients with a BDST score ≥6, the likelihood ratio of a positive test was 2.67. The sensitivity was 85% (95% confidence interval [CI]: 89%–96%) and the specificity was 68% (95% CI: 60%–76%). The area under the curve was 84% (95% CI: 80%–87%). CONCLUSION: This audit validates BDST against PHQ-9 and finds it an excellent case-finding tool compared to PHQ-9. This is the first validation study of BDST.