Significance of self-reported sleep quality (SQ) in chronic kidney disease (CKD): the Renal Research Institute (RRI)-CKD study

Abstract

There has been limited research on sleep quality (SQ) in CKD. This prospective cohort study of adults with CKD Stages 3 - 5 at four US centers collected self-reported SQ information from the Kidney Disease Quality of Life (KDQOL) instrument, including an estimated SQ score (0 - 100), and 3 SQ-related questions. "Poor" SQ was defined as SQ score < or = 60. Logistic and multiple linear regression assessed associations between SQ and its potential predictors. Times to death and end stage renal disease (ESRD) were examined using Cox regression. A comparison with SQ in ESRD patients from the Dialysis Outcomes and Practice Patterns Study (DOPPS), was additionally performed. Mean SQ score was 59.4 +/- 23.6 (n = 689), and "poor" SQ was reported by 57%. Mean estimated glomerular filtration rate (eGFR) was 24.9 +/- 10.6 ml/min/1.73 m2. Higher SQ significantly correlated with KDQOL mental and physical component summary scales. Significant predictors of lower SQ score included--younger age, presence of dyspnea, self-reported depression, pain, and itchness. There were no significant pairwise differences in SQ from CKD Stage 3 through ESRD. Self-reported daytime sleepiness was significantly associated with higher risk of mortality prior to ESRD (HR = 1.85, p = 0.02). Self-reported "poor" SQ was common in a CKD cohort (Stages 3 - 5) and was not only associated with lower quality of life scores and several modifiable symptoms, but also with higher risk of pre-ESRD mortality. Greater attention to this clinical problem is highly recommended in this high-risk population.