Background: Patient-reported outcome measures that are more practical and clinically useful are needed for patients with CKD. We compared a new CKD-specific quality-of-life impact scale (CKD-QOL) with currently used measures.
Methods: Patients (n=485) in different treatment groups (nondialysis stages 3-5, on dialysis, or post-transplant) completed the kidney-specific CKD-QOL and Kidney Disease Quality of Life-36 (KDQOL-36) forms and the generic SF-12 Health Survey at baseline and 3 months. New items summarizing quality of life (QOL) impact attributed to CKD across six QOL domains yielded single impact scores from a six-item static (fixed-length) form and from computerized adaptive tests (CATs) with three to six items. Validity tests compared the CKD-QOL, KDQOL-36 (Burden, Effects, and Symptoms/Problems subscales), and generic SF-12 measures across groups in four tests of clinical status and clinician assessment of change (CKD-specific tests), and number of comorbidities. ANOVA was used to test for group mean differences, variances in each measure explained by groups, and relative validity (RV) in comparison with the referent KDQOL-36 Burden subscale.
Results: KDQOL-36 and CKD-QOL measures generally discriminated better than generic SF-12v2 measures. The pattern of variances across CKD-specific tests comparing validity favored CKD-QOL two-fold over KDQOL-36. Two RV test results confirmed CKD-QOL improvements over the referent KDQOL scale. Results for static and CAT CKD-QOL forms were similar. SF-12 Physical and KDQOL-36 Symptoms scores worsened with increasing comorbid condition counts.
Conclusions: Overall, compared with the KDQOL-36, the new approach to summarizing CKD-specific QOL impact performed better across multiple tests of validity. CAT surveys were more efficient than static surveys.
Keywords: KDQOL; Patient-Reported Outcomes; SF-12 Health Survey; chronic kidney disease; quality of life.
Copyright © 2019 by the American Society of Nephrology.