Analysis of agreement between Visual Analogue Scales (VAS) and numerical questions to assess perception of teratogenic risks in treatment with drugs and radiotherapy in women

Objectives: to evaluate the agreement between Visual Analogue Scales (VAS) and numerical questions as a way of assessing the perception of teratogenic risk of treatment with drugs and radiotherapy. Methods: the sample comprised 144 pregnant and 143 non-pregnant women consecutively recruited at public health centers in Porto Alegre, in the State of Rio Grande do Sul, from February to August 2011. The perception of risk for congenital malformations in the general population and the perceptions of teratogenic risk for exposure to acetaminophen, meto-clopramide, misoprostol and radiotherapy were measured using VAS and numerical questions. The agreement between the results of the two techniques was tested using a Bland-Altman plot. Results: the medians for the perceptions measured using VAS were higher than those obtained using numerical questions for all variables. The perception of risk for acetaminophen showed the lower bias of the two techniques (bias=13.17; p<0.001) and exposure to radiotherapy, the higher (bias=25.02; p