Association of Sleep Apnea with Mortality in Patients with Advanced Kidney Disease

Abstract

Background and objectivesIn the general population, sleep disorders are associated with mortality. However, such evidence in patients with CKD and ESKD is limited and shows conflicting results. Our aim was to examine the association of sleep apnea with mortality among patients with CKD and ESKD.Design, setting, participants, & measurementsIn this prospective cohort study, 180 patients (88 with CKD stage 4 or 5, 92 with ESKD) underwent in-home polysomnography, and sleep apnea measures such as apnea hypopnea index (AHI) and nocturnal hypoxemia were obtained. Mortality data were obtained from the National Death Index. Cox proportional hazard models were used for survival analysis.ResultsAmong the 180 patients (mean age 54 years, 37% women, 39% with diabetes, 49% CKD with mean eGFR 18±7 ml/min per 1.73 m2), 71% had sleep apnea (AHI>5) and 23% had severe sleep apnea (AHI>30). Median AHI was 13 (range, 4–29) and was not significantly different in patients with advanced CKD or ESKD. Over a median follow-up of 9 years, there were 84 (47%) deaths. AHI was not significantly associated with mortality after adjusting for age, sex, race, diabetes, body mass index, CKD/ESKD status, and kidney transplant status (AHI>30: hazard ratio [HR], 1.5; 95% confidence interval [95% CI], 0.6 to 4.0; AHI >15 to 30: HR, 2.3; 95% CI, 0.9 to 5.9; AHI >5 to 15: HR, 2.1; 95% CI, 0.8 to 5.4, compared with AHI≤5). Higher proportion of sleep time with oxygen saturation <90% and lower mean oxygen saturation were significantly associated with higher mortality in adjusted analysis (HR, 1.4; 95% CI, 1.1 to 1.7; P=0.007 for every 15% higher proportion, and HR, 1.6; 95% CI, 1.2 to 2.1; P=0.003 for every 2% lower saturation, respectively). Sleep duration, sleep efficiency, or periodic limb movement index were not associated with mortality.ConclusionsHypoxemia-based measures of sleep apnea are significantly associated with increased risk of death among advanced CKD and ESKD.

Sleep apnea is associated with residual kidney function and mortality in patients with peritoneal dialysis: Prospective cohort study

“…In the present study, moderate-to-severe SA was common in PD patients and was an independent risk factor for mortality even after adjusting for confounding factors. Although these findings are in accordance with previously published research in CKD and HD patients, 23,24 this study is meaningful because the results were derived from a relatively large number of PD patients who were followed up for a long period. In addition to the previous study with relatively small number of PD patients, 25 this study showed RKF as well as fluid overload were closely associated with SA severity in PD patients.…”

Sleep Apnea and the Kidney

“…This is in agreement with observations in other populations reporting a lower coronary and mortality risk, if not an advantage, in elderly OSA patients [42,43]. Mortality risk in middle-aged ESRD patients was related to nocturnal hypoxemia, and not to AHI [40], as already found in a previous small study [44].…”

“…Improvement of SDB, obtained with reduction in body fluids by plasma ultrafiltration, may blunt such deterioration [37••]. Recent studies have shown that, in the long term, OSA may increase cardiovascular and all-cause mortality in middle-aged ESRD patients [39,40]. This effect was not demonstrated in older patients who, rather the opposite, showed a lower risk of all-cause death, myocardial infarction, and ischemic stroke when they had been diagnosed with OSA [41].…”

Sleeping, Smoking, and Kidney Diseases: Evidence From the NHANES 2017–2018

“…SA is a condition that has serious health consequences, has an increased risk of death, and is common in patients with CKDs (43,44) and DKD (45). Obstructive SA-related hypoxia causes several negative systemic effects, including oxidative stress (46,47), inflammation, and sympathetic activation, all of which contribute to the progression of renal disease. In turn, CKD can result in the increased severity of SA by inducing uremic neuropathy and myopathy, altered chemosensitivity, and hypervolemia (43).…”