Measurement properties of the Brazilian version of the Kidney Symptom Questionnaire

The aim of this study was to measure the reliability, internal consistency, and construct validity of the Kidney Symptom Questionnaire for the Brazilian population.

This is a cross-cultural adaptation and questionnaire validation study. We included native Brazilians of both sex aged>18 years, as well as hypertensive and/or diabetic patients. All participants were assessed using Screening for Occult Renal Disease, EuroQol 5 Dimensions, 36-Item Short Form Survey, and the Kidney Symptom Questionnaire. We used Spearman's coefficient (rho) to measure the correlations between the Kidney Symptom Questionnaire and other instruments; Cronbach's alpha to measure internal consistency; and intraclass correlation coefficient, standard error of measurement, and minimum detectable change to measure test-retest reliability.

The sample was formed by 121 adult participants, mostly female, with systemic arterial hypertension and/or diabetes mellitus. We found excellent reliability (intraclass correlation coefficient≥0.978), adequate internal consistency (Cronbach's alpha≥0.860), and adequate construct validity on the Kidney Symptom Questionnaire domains; besides, we observed significant correlations between the Kidney Symptom Questionnaire and other instruments.

The Brazilian version of the Kidney Symptom Questionnaire has adequate measurement properties to assess chronic/occult kidney disease in patients who do not require renal replacement therapy.