CKD, its comorbid conditions, and its treatment substantially burden patients’ health-related quality of life (QOL). Kidney diseases, even those with diverse clinical presentations such as polycystic kidney disease and nephrotic syndrome; are with substantial QOL impairment. Generic QOL measures have the advantage of enabling comparisons of disease burden across CKD and other conditions; whereas disease-specific measures have the advantages of greater validity; including responsiveness, for a specific condition.
The most common generic QOL tools used in CKD are the Short Form-36 Health Survey5–8 and its 12-item subset, the Short Form-12 Health Survey.9 The disease-specific tool most commonly used in kidney disease, the Kidney Disease Quality of Life 36-Item Short Form Survey (KDQOL-36), measures both CKD-specific and generic QOL domains.
New chronic kidney disease
CKD measure of the quality of life (QOL) and a single-score summary for the Kidney Disease Quality of Life-36 (KDQOL-36) are both reliable for assessing patient-reported outcomes and quality of life. But Massachusetts and colleagues compared a new CKD-specific QOL impact scale (CKD-QOL) with KDQOL-36 forms and the generic Short Form-12v2 Health Survey (SF12v2); among 145 patients in different treatment groups.
The researchers found that compared with the generic SF-12v2 measures; KDQOL-36 and CKD-QOL measures generally discriminated better. Across four CKD-specific tests, the pattern of comparative results favored CKD-QOL over KDQOL-36 scales. To simplify interpretation of KDQOL-36 scores by developing a composite score (the KDQOL-36 Summary Score [KSS]) for the kidney-targeted KDQOL-36 scales using a sample of 58,851 dialysis patients participating in the KDQOL Complete program and 443,947 patients from the United States Renal Data System.
The confirmatory factor analysis (CFA) model fit was evaluated. The researchers found that a bifactor CFA model fit the data well and supported the KSS (α = 0.91). “There is the opportunity for increased application of patient-reported outcomes to improve clinical monitoring of patients’ health and treatment evaluation in end-stage kidney disease;” write the authors of an accompanying editorial.
CKD-quality of life measures
Therefore one author from the Ware study disclosed financial ties to the pharmaceutical industry and reported the development of CKD-QOL measures. These results support the hypothesized advantages of a new approach to CKD-specific QOLimpactmeasurement. The new CKD-QOL measures improved validity in head-to-head comparisons with generic SF-12v2 and CKD-specific KDQOL-36 measures.
In addition to self-evaluated severity; multiple clinical comparisons included differences across treatment status groups, severity (eGFR) within the nondialysis groups; responsiveness to clinician-evaluated change in severity. In summary; results from comparisons of measures across groups in four CKD-specific validation tests; showed that KDQOL-36 and CKD-QOL measures have greater discriminant validity than generic SF-12v2 in nearly all tests.