Measuring anxiety and depression in the oncology setting using visual-digital scales

We investigated the feasibility of using single-item visual-digital scales for measuring anxiety and depression for research purposes within the oncology and palliative care setting. Data were retrieved from five nationwide postal questionnaires comprising 3030 individuals (response rate 76%): cancer patients, widows/parents who had lost their husband/child to cancer and population controls. All questionnaires contained the Center for Epidemiological Studies Depression scale (CES-D) and Spielberger's State-Trait Anxiety Inventory (STAI-T) as well as seven-point Visual-Digital Scales (VDS) assessing anxiety and depression. Each stepwise increased score on the VDS-depression provided a statistically significant increase in the mean score on CES-D (Spearman's r=0.582). The VDS-anxiety correlated with mean scores on STAI-T (Spearman's r=0.493), however, not all stepwise increased scores on the VDS-anxiety gave a statistically significant increase on the STAI-T. Positive- and negative predictive values were 51% and 91% for VDS-depression and 64% and 80% for VDS-anxiety. Missing data for STAI-T were 7% and 9% for CES-D; the corresponding figures were 2% for the VDS-depression and 3% for VDS-anxiety. With low attrition and agreement with psychometric scales, the Visual-Digital Scales are a feasible alternative for research in the oncology setting. However, the high negative predictive value and the low positive predictive value suggest that the visual- digital scales mainly detect the absence of the symptoms.