Scores are reported separately for each of the five KDQOL-36 subscales. Arbor Research Collaborative for Health supplied KDQOL-36 data from 1,282 U.S. prevalent in-center hemodialysis patients. Arbor statisticians determined that gender (M/F), diabetes (Y/N), and age (<45, 45-64, 65-74, 75+) were the demographic characteristics associated with the greatest variability in KDQOL-36 scores. (NOTE: Race was examined, but did not contribute as much variation as the others).
Arbor provided means and standard deviations (SD) for each of the 16 cells a given respondent can belong to (2 cells for sex • 2 cells for diabetes • 4 cells for age). Based on these data, KDQOL Complete reports individual patient subscale scores by tertiles (thirds):
- More than one SD above the mean is the “above average” tertile
- The mean +/- one SD is “average”
- More than one SD below the mean is the “below average” tertile
In this way, patients are compared to others who are like themselves in terms of age, gender, and presence/absence of diabetes.