Patients with advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) patients have similar sleep apnea severity and are at greater death risk than patients without the sleep disorder, new study findings published in the Clinical Journal of the American Society of Nephrology suggest.
Manisha Jhamb, MD, MPH, of the University of Pittsburgh, and colleagues examined sleep apnea severity in 88 patients with CKD stage 4 and 5 and 92 patients with ESRD (72 on hemodialysis [HD] and 20 on peritoneal dialysis [PD]). Patients had a mean age of 54 years. The study population was 37% female, and 39% of patients had diabetes.
Based on in-home polysomnography results, 71% had any sleep apnea (defined as apnea hypopnea index [AHI] higher than 5 episodes of no breathing or shallow breathing per hour), and 23% had severe sleep apnea (AHI higher than 30 per hour).
Over a median 9 years, 84 patients died. Patients who spent more sleep time at lower oxygen saturations (lower mean oxygen saturation and more total time below 90%) were significantly more likely to die. In adjusted analyses, every 2% decrease in mean oxygen was significantly associated with a 60% higher death risk. Every 15% worsening in nocturnal hypoxemia was significantly associated with a 40% increase in death risk. Other objective sleep measures — AHI, sleep duration, sleep efficiency, or periodic limb movement index — were not significantly associated with mortality.
According to the investigators, hypoxemic burden may be the driving force leading to elevated oxidative stress, coronary calcification, sympathetic hyperactivity, systemic inflammation, and left ventricular hypertrophy.
The study expands on prior research by incorporating a larger more diverse CKD/ESRD population followed over a longer period, and it adjusted for several important confounders, such as kidney transplant status.
“Given the strong association of nocturnal mean oxygen saturation with mortality, further studies are needed to evaluate whether screening all patients with CKD or ESKD with a simple overnight home pulse oximetry device is warranted,” Dr Jhamb’s team stated.
Future studies also should test if supplemental oxygen alone versus continuous positive airway pressure reduces hypoxemic burden and improves survival, they noted.
Jhamb M, Ran X, Abdalla H, et al. Association of sleep apnea with mortality in patients with advanced kidney disease [published online January 22, 2020]. Clin J Am Soc Nephrol. doi: 10.2215/CJN.07880719