Italian translation, cultural adaptation and validation of KDQOL-SF, version 1.3, in patients with severe renal failure

Background: This study aims to confirm the reliability and validity of the KDQOL-SF in its Italian version. Cultural adaptation of such an instrument to assess quality of life of patients with chronic kidney disease is a major challenge. Methods: The instrument was translated according to the translation algorithm. A trained psychologist administered the KDQOL-SF to 188 patients. Results: Completeness was optimal. Item internal consistency was satisfied for 74.5% and 87.5% of patients for the kidney and generic part, respectively. Discriminant validity was satisfied for 96.3% and 98.6% of patients. Cronbach's α coefficient was >70% in 70% and 75% of patients. While assessing the responsiveness (external discriminating validity) of KDQOL-SF, we found lower scores (worse functioning and well-being) in females, patients aged 65 years or older, with low hemoglobin, hematocrit and high Kt/V, and in patients with a diagnosis of amyloidosis. Moreover, the score for physical health was lower in the absence of dialytic treatment and with a longer history of dialysis. The score for mental health was lower for lower creatinine levels and for a shorter dialytic history. The disease targeted score was lower in the absence of dialytic treatment, and the score for patient satisfaction was lower in the presence of dialytic treatment and for a longer dialytic history. Conclusions: The Italian translation of KDQOL-SF sounds natural, is easy to understand and reduces possible cultural biases to a minimum. A field test gave results comparable to other international validations, supporting the use of KDQOL-SF in cross-national surveys