Problems with analyses and interpretation of data in "use of the KDQOL-36™ for assessment of health-related quality of life among dialysis patients in the United States"

A recent article in the journal reported analyses of KDQOL-36™ survey data collected from 240,343 adults (330,412 surveys) dialyzed at a large dialysis organization in the United States during 2014-2016. The authors concluded that the KDQOL-36™ Symptoms and Problems of Kidney Disease scale had the highest mean score of the KDQOL-36™ scales. We note that this inference was erroneous because the scales are not scored on the same numeric scale. In addition, the authors found that responses to a general health perceptions item ("In general, would you say your health is excellent, very good, good, fair, or poor") was not significantly associated with any of the 5 KDQOL-36 scale scores. In contrast, we find significant and noteworthy correlations in two other datasets. These analytic issues call into question the accuracy and validity of the conclusions of this paper.