Development of the kidney disease quality of life (KDQOL) instrument.

This paper describes the Kidney Disease Quality of Life (KDQOL) Instrument (dialysis version), a self-report measure that includes a 36-item health survey as the generic core, supplemented with multi-item scales targeted at particular concerns of individuals with kidney disease and on dialysis (symptom/problems, effects of kidney disease on daily life, burden of kidney disease, cognitive function, work status, sexual function, quality of social interaction, sleep). Also included were multi-item measures of social support, dialysis staff encouragement and patient satisfaction, and a single-item overall rating of health. The KDQOL was administered to 165 individuals with kidney disease (52% female; 48% male; 47% White; 27% African-American; 11% Hispanic; 8% Asian; 4% Native American; and 3% other ethnicities), sampled from nine different outpatient dialysis centres located in Southern California, the Northwest, and the Midwest. The average age of the sample was 53 years (range from 22 to 87), and 10% were 75 years or older. Internal consistency reliability estimates for the 19 multi-item scales exceeded 0.75 for every measure except one. The mean scores for individuals in this sample on the 36-item health scales were lower than the general population by one-quarter (emotional well-being) to a full standard deviation (physical function, role limitations due to physical health, general health), but similar to scores for dialysis patients in other studies. Correlations of the KDQOL scales with number of hospital days in the last 6 months were statistically significant (p < 0.05) for 14 of the 19 scales and number of medications currently being taken for nine of the scales. Results of this study provide support for the reliability and validity of the KDQOL.