Validation of the KDQOL-SF: a dialysis-targeted health measure

Abstract

Background: In evaluations of dialysis therapy, an assessment of health-related quality of life (HRQOL) is often important. The aim of this study was to determine the basic psychometric properties, reliability and validity of the short form of the KDQOL i.e. the KDQOL-SF, a dialysis-targeted instrument, and to assess its ability to detect changes over time.

Methods: In a prospective cohort study (Netherlands Cooperative Study on the Adequacy of Dialysis, NECOSAD), all new adult ESRD patients in 32 different Dutch centers were consecutively enrolled. Demographic, clinical and HRQOL data were obtained 3 and 12 months after the start of chronic dialysis therapy.

Results: The reliability of the KDQOL-SF was supported by test results that were above the recommended minimal values. Validity of KDQOL-SF was confirmed by the hypothesized positive correlations of the overall health rating and renal function, and by the negative correlations between the number of comorbidities and dialysis dose. Moreover, dialysis-targeted dimensions were more sensitive in detecting relevant differences pertaining to kidney diseases than generic dimensions. The KDQOL-SF was able to detect clinical changes over time.

Conclusions: The psychometric properties of the KDQOL-SF were good, and the different dialysis-targeted dimensions were informative with a high reliability and validity. These results support the application of the KDQOL-SF in studies evaluating dialysis therapy.