ABSTRACT
INTRODUCTION: In general populations, short and long sleep duration, poor sleep quality and sleep disorders have been associated with increased risk of death. We evaluated these associations in individuals with chronic kidney disease (CKD). METHODS: Prospective cohort study of 1,452 National Health and Nutrition Examination Survey (NHANES) 2005-2008 participants with CKD. CKD was defined by estimated glomerular filtration rate <60 ml/min/1.73m2 or urine albumin-to-creatinine ratio ≥30 mg/g. Sleep duration, sleep symptoms (difficulty falling asleep, difficulty staying asleep, daytime sleepiness and non-restorative sleep), and sleep disorders (restless legs syndrome and sleep apnea) were self-reported. Vital status was determined using NHANES mortality linkage through December 2011. RESULTS: Mean age was 61 years, 58% were women, and 75% non-Hispanic white. During 4.4 years of median follow-up, we observed 234 deaths of which 75 were due to cardiovascular causes. In multivariable analyses, compared with individuals who reported 7-8 hours of sleep, HR (95% CI) for all-cause mortality for sleep duration <7 hours and >8 hours were 1.50 (1.08-2.10) and 1.36 (0.89-2.08), respectively. The corresponding HR (95%CI) for cardiovascular mortality were 1.56 (0.72-3.37) and 1.56 (0.66-3.65). Non-restorative sleep and restless legs syndrome were associated with increased risk for all-cause mortality (1.63 [1.13-2.35], and 1.69 [1.04-275], respectively). CONCLUSION: In adults with CKD, short sleep duration, nonrestorative sleep and restless legs syndrome are associated with increased risk of death. These findings underscore the importance of promoting adequate sleep in patients with CKD, and the need for future studies evaluating the impact of sleep interventions in this population.
ABSTRACT
BACKGROUND: Retinopathy is associated with increased mortality risk in general populations. We evaluated the joint effect of retinopathy and chronic kidney disease (CKD) on mortality in a representative sample of U.S. adults. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: 7,640 adults from NHANES (National Health and Nutrition Examination Survey) 1988-1994 with mortality linkage through December 31, 2006. PREDICTORS: CKD, defined as low estimated glomerular filtration rate (<60 mL/min/1.73 m2) or albuminuria (urine protein-creatinine ratio ≥30 mg/g), and retinopathy, defined as the presence of microaneurysms, hemorrhages, exudates, microvascular abnormalities, or other evidence of diabetic retinopathy by fundus photograph. OUTCOMES: All-cause and cardiovascular mortality. MEASUREMENTS: Multivariable-adjusted Cox proportional hazards. RESULTS: Overall, 4.6% of participants had retinopathy and 15% had CKD. Mean age was 56 years, 53% were women, and 81% were non-Hispanic whites. The prevalence of retinopathy in patients with CKD was 11%. We identified 2,634 deaths during 14.5 years' follow-up. In multivariable analyses, compared with individuals with neither CKD nor retinopathy, HRs for all-cause mortality were 1.02 (95% CI, 0.75-1.38), 1.52 (95% CI, 1.35-1.72), and 2.39 (95% CI, 1.77-3.22) for individuals with retinopathy only, those with CKD only, and those with both CKD and retinopathy, respectively. Corresponding HRs for cardiovascular mortality were 0.96 (95% CI, 0.50-1.84), 1.72 (95% CI, 1.47-2.00), and 2.96 (95% CI, 2.11-4.15), respectively. There was a significant synergistic interaction between retinopathy and CKD on all-cause mortality (P=0.04). LIMITATIONS: The presence of retinopathy was evaluated only once. Small sample size of some of the subpopulations studied. CONCLUSIONS: In the presence of CKD, retinopathy is a strong predictor of mortality in this adult population.
