Acurácia do Walking Impairment Questionnaire na avaliação da capacidade funcional de indivíduos com claudicação intermitente

Abstract

The assessment of walking capacity in subjects with Peripheral Arterial Disease (PAD) is part of the recommendations for clinical practice. In cardiovascular rehabilitation, the use of questionnaires has increased and presents validation for the investigation of different outcomes, including the perception of the walking capacity. The use of simple tools, such as the Walking Impairment Questionnaire (WIQ), to identify who is at functional risk due to PAD, can facilitate and speed up the referral to other assessments and treatments. Thus, the aim of this study was to analyse the accuracy of the WIQ in evaluating of the functional capacity of subjects with PAD, and to determine the cutoff point with better sensitivity and specificity for identifying low functional capacity. This is an exploratory observational study that analyzed data from a retrospective longitudinal design. The walking capacity was assessed by Incremental Shuttle Walk Testing (ISWT) and the perception of the walking capacity was assessed by WIQ. Continuous and categorical data have been described with corresponding measurements and frequencies. The data normality was assessed using the Shapiro-Wilk test. An analysis of the accuracy, sensitivity and specificity of the average WIQ score was analyzed using the Receiver Operating Characteristic curve. The alpha of 5% was considered for statistical significance. Complete data were collected from 121 participants. Mean age was 64 years ± 9.68 years and most participants were male. The mean distance walking in the ISWT was 270.6 ± 100.2 meters. As a reference, a walking distance of 380 meters on the ISWT, a final score of 37.04 on the WIQ was identified as a cutoff point, with a sensitivity of 0.75 and a specificity of 0.62 (area under the curve - AUC = 0.73, p = 0.003, 95% CI 0.61–0.86). Based on the reference of 100 meters walked in the ISWT, the cutoff point found was 13.97 (AUC = 0.77, p = 0.0001, 95% CI 0.64–0.91), with a sensitivity of 0. 78 and specificity of 0.83. The final WIQ score of 14 points was the one with the best accuracy in differentiating individuals with low and high functional capacity. This cutoff point can be used in scientific research or in clinical practice, in order to identify individuals with greater functional impairments so that they can be referred for more comprehensive evaluations and have faster access to rehabilitation. Thus, further studies are needed to assess the usefulness of the WIQ as a screening tool in this population.