Transcultural adaptation of the Thirst Distress Scale (TDS) into Brazilian Portuguese and an analysis of the psychometric properties of the scale for patients on hemodialysis

OBJECTIVE: To produce a transcultural adaptation of the Thirst Distress Scale (TDS) into Brazilian Portuguese and analyze the scale’s psychometric properties for patients on hemodialysis (HD). METHODS: The original scale was translated, back translated, and discussed with psychometric assessment experts. The final version was tested with 126 patients on HD and retested with 70 individuals from the original patient population. Cronbach’s alpha was used to measure the scale’s internal consistency. Reliability of thirst intensity evaluated via the visual analogue scale (VAS) was tested with Kappa statistic and the Bland-Altman plot. Reproducibility was assessed based on the intraclass correlation coefficient (ICC). RESULTS: The wording of three items and the verb tenses of six had to be adjusted in the final version of the Brazilian Portuguese TDS. Comprehension of the scale by patients on HD was good, the scale’s internal consistency was satisfactory (0.84; p<0.001), agreement with a visual analogue scale (VAS) was moderate (kappa=0.44; p<0.001), and reproducibility neared perfection (ICC=0.87; p<0.001). CONCLUSION: Our results showed that the Brazilian Portuguese version of the scale might be used reliably. The Brazilian Portuguese version of the TDS is a practical, affordable, accessible and well-accepted tool that has a lot to offer for the management of patients with HD.