Reliability and validity of the Persian version of 5-D itching scale among patients with chronic kidney disease

BACKGROUND: Hemodialysis is considered a major therapeutic method for patients with chronic kidney disease. Pruritus is a common complaint of hemodialysis patients. The 5-D pruritus scale is amongst the most common tools to evaluate several dimensions of itch. Psychometric properties of the 5-D scale have not been evaluated in Persian speaking population with hemodialysis; hence, the objective of this study was to assess reliability and validity of the Persian version of the scale. METHODS: Ninety hemodialysis patients (men: 50, women: 40, mean age: 54.4 years) participated in this cross-sectional study. The final Persian version of 5-D scale was given to the participants. Tests Compared: One-third of the participants completed the scale twice within 3–7 days apart to evaluate test- retest reliability. Other psychometric properties including internal consistency, absolute reliability, convergent, discriminative and construct validity, floor/ceiling effects were also evaluated. RESULTS: The Persian 5-D scale has strong test-retest reliability (ICC= 0.98) and internal consistency (Cronbach’s alpha= 0.99). Standard error of measurement and minimal detectable change were 0.33 and 0.91, respectively. Regarding convergent validity, the scale had moderate correlation with numeric rating scale (r =0.67) and quality of life questionnaire related to itch (r = 0.59). Exploratory factor analysis revealed two factors within the scale. No floor or ceiling effect was found for the scale. CONCLUSION: The Persian version of 5-D the itching scale is a brief instrument with acceptable reliability and validity. Therefore, the scale could be used by experts, nurses, and other health service providers to evaluate pruritus among Persian speaking hemodialysis patients. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12882-020-02220-x.