Table 1.
Summary of information for CKD-specific and generic measures (n=485)
| Measure/Scoring | k | % Missing | Mean (SD) | Reliabilitya | Interpretation of Lowest Score | Interpretation of Highest Score | |
|---|---|---|---|---|---|---|---|
| Internal Consistency | Test-Retest | ||||||
| KDQOL-36 | |||||||
| Burden (+) | 4 | 1.0 | 61.0 (29.5) | 0.88 | 0.79 | Kidney disease interferes with life, frustrating, feels like burden on family | Kidney disease does not interfere with life, is not frustrating, does not feel like burden on family |
| Effects (+) | 8 | 1.4 | 72.2 (22.4) | 0.86 | 0.86 | Extremely bothered by eight effects of kidney disease on daily life | Not at all bothered by eight effects of kidney disease on daily life (see Figure 2) |
| Symptoms/Problems (+) | 12 | 1.2 | 75.8 (17.0) | 0.86 | 0.85 | Extremely bothered by 12 symptoms | Not at all bothered by 12 symptoms (see Figure 2) |
| CKD-QOL | |||||||
| CKD-QOL-6 (−) | 6 | 0.2 | 47.6 (9.3) | 0.94 | 0.89 | No impact on role, social, emotional, cognitive functioning, fatigue, or quality of life because of kidney disease | Severe and frequent impact on role, social, emotional, cognitive functioning, fatigue, quality of life because of kidney disease |
| CKD-QOL-CAT −) | 6 | 0.0 | 47.1 (10.2) | 0.93b | 0.89 | (Same as above) | (Same as above) |
| 3- or 6-item CAT (−) | 3–6 | 0.0 | 47.4 (10.0) | 0.90b | 0.88 | (Same as above) | (Same as above) |
| SF-12v2 | |||||||
| PCS (+) | 12 | 3.7 | 40.4 (11.1) | 0.89 | 0.87 | Limited physical, work, or daily activities; severe pain; low energy; health poor | No limits in physical, work, or daily activities; no pain; high energy; health excellent |
| MCS (+) | 12 | 3.7 | 50.1 (10.4) | 0.84 | 0.84 | Frequent emotional distress and low energy; limited in everyday activities because of emotional problems | Frequent positive affect, not at all limited in everyday activities because of emotional problems |
Scoring: (+) higher score is better, (−) lower score is better. k, number of items.
Reliability: internal-consistency reliability for scales estimated with Cronbach α. Test-retest reliability estimated with intraclass correlation; sample size is n=65 for KDQOL-36 and CKD-QOL measures, and n=61 for SF-12v2 PCS/MCS. Reliability for PCS/MCS estimated on the basis of reliability of eight SF-12v2 scales, scale covariances, and scale weights used to estimate each component.48
Mean reliability for CKD-QOL-CAT and three or six-item CAT on the basis of SEM for each patient score. Percentage of patients (for three- or six-item CKD-QOL-CAT) with reliability ≥0.90 is 78%/66%, reliability ≥0.80 is 82%/73%, and reliability ≥0.70 is 100%/100%.49