Turkish version of the Johns Hopkins Restless Legs Syndrome Quality of Life Questionnaire (RLS-QoL): validity and reliability study.

Abstract

Restless legs syndrome (RLS), as well as problems secondary to RLS, may worsen the quality of life. Our aim was to modify the Restless Legs Syndrome Quality of Life (RLS-QoL) questionnaire advanced by Abetz (Health Qual Life Outcomes 3:79, 2005) and to analyse the validity and reliability of the questionnaire. Two hundred and one consecutive patients with RLS and forty-three control subjects were included in the study. Permission regarding the translation and validation of the RLS-QoL questionnaire was obtained. The translation was conducted according to the guidelines provided by the publisher. For the RLS subjects, the mean Insomnia Severity Index (ISI) score, the International Restless Legs Syndrome Severity Rating Scale (IRLSSG) score and the computed score of the RLS-QoL questionnaire were 22.60 ± 3.39, 24.83 ± 5.28 and 45.93 ± 17.62, respectively. Among the RLS subjects without insomnia, the mean (±standard deviation) ISI score, IRLSSG score and computed score of the RLS-QoL questionnaire were 6.67 ± 2.34, 15.11 ± 4.03 and 41.93 ± 16.12, respectively. A significant difference was identified between both groups on all scores (ISI: p = 0.001, RLS: p = 0.001). The groups with and without insomnia were similar regarding the computed score of the RLS-QoL questionnaire (p = 0.140). According to a correlation analysis, a significant correlation was identified between the ISI and IRLSSG or RLS-QoL scores (r = 0.513, p = 0.001 and r = -0.383, p = 0.001, respectively). Although the coefficient of correlation is significant between IRLSSG score and RLS-QoL scale score, it should not be considered as a powerful enough correlation (r = 0.190, p = 0.007). Most items also exhibited a strong correlation with each other. The internal consistency determined by Cronbach's alpha indicated an extremely good correlation (0.975). These findings suggest the Turkish version of the RLS-QoL questionnaire is a valid and reliable tool for the assessment of the quality of life in patients with RLS.