Prevalence and Diagnostic Approach to Sleep Apnea in Hemodialysis Patients: A Population Study

Abstract

Background. Previous observations found a high prevalence of obstructive sleep apnea (OSA) in the hemodialysis population, but the best diagnostic approach remains undefined. We assessed OSA prevalence and performance of available screening tools to propose a specific diagnostic algorithm. Methods. 104 patients from 6 Swiss hemodialysis centers underwent polygraphy and completed 3 OSA screening scores: STOP-BANG, Berlin's Questionnaire, and Adjusted Neck Circumference. The OSA predictors were identified on a derivation population and used to develop the diagnostic algorithm, which was validated on an independent population. Results. We found 56% OSA prevalence (AHI ≥ 15/h), which was largely underdiagnosed. Screening scores showed poor performance for OSA screening (ROC areas 0.538 [SE 0.093] to 0.655 [SE 0.083]). Age, neck circumference, and time on renal replacement therapy were the best predictors of OSA and were used to develop a screening algorithm, with higher discriminatory performance than classical screening tools (ROC area 0.831 [0.066]). Conclusions. Our study confirms the high OSA prevalence and highlights the low diagnosis rate of this treatable cardiovascular risk factor in the hemodialysis population. Considering the poor performance of OSA screening tools, we propose and validate a specific algorithm to identify hemodialysis patients at risk for OSA for whom further sleep investigations should be considered.

Impact of kidney transplantation on sleep apnea severity: A prospective polysomnographic study

“…The screening phase of our study represents the largest cohort of ESKD patients on a kidney transplant waiting list studied by full PSG (n = 196). It shows a remarkably high prevalence of moderate to severe SA in this population (44.9%), consistent with the figures obtained in patients on dialysis . Our data add new insights to the existing evidence from previous observational and interventional studies, which identified fluid overload as a population‐specific pathophysiological mechanism of SA in ESKD patients, promoting SA through the so‐called “overnight rostral fluid shift.” Accordingly, the negative fluid balance obtained by hemodialysis has been shown to decrease the severity of SA in overhydrated ESKD patients, even in the absence of any change of the uremic and acid‐base status .…”

“…Kidney transplantation (Tx) restores kidney function and corrects the hydration status of ESKD patients. A previous polysomnographic study reported a SA prevalence of 22% in kidney Tx recipients, which is similar to the prevalence of SA in the general population and lower than that in ESKD patients on hemodialysis . This observation indirectly suggests a beneficial effect of kidney Tx on SA severity.…”

“…Finally, we observed no significant change in the prevalence of daytime sleepiness after Tx (as assessed by the Epworth Sleepiness Scale score). However, it should be noted that previous studies performed both in the ESKD population as well as in the general population showed no correlation between daytime sleepiness and severity of SA …”

“…This may be explained in part by the increased prevalence both of SA and CKD as individuals get older and by an increasing prevalence of obesity in the general population. However, the association between SA and ESKD persists after correction for potential confounding factors such as diabetes, hypertension, and obesity, supporting a direct association between SA and ESKD . Fluid overload has been suggested as the main population‐specific pathophysiological mechanisms linking SA and ESKD, which would add on classical risk factors for SA, such as age, increased body mass index (BMI), or upper airway anatomy.…”

Chronic kidney disease in European patients with obstructive sleep apnea: the ESADA cohort study

“…The relationship between OSA and CKD has been the object of great interest. In patients with end‐stage renal disease (Forni Ogna et al ., ; Kuhlmann et al ., ; Unruh et al ., ), as well as with less severe forms of CKD (Nicholl et al ., ; Sakaguchi et al ., ), a high prevalence of OSA has been reported. Among other mechanisms, renal failure could promote OSA by causing increased chemoresponsiveness or increased fluid retention and upper airway collapsibility through rostral fluid shift when assuming a recumbent position (Abuyassin et al ., ; Lyons et al ., ).…”