Can Treatment of Obstructive Sleep Apnea with Continuous Positive Airway Pressure Still Improve Kidney Outcomes?

Sleep disorders in chronic kidney disease

Sleep disorders are highly prevalent in chronic kidney disease (CKD) but are often under-recognized. Restless legs syndrome, which is common in CKD owing to issues with dopamine metabolism and is exacerbated by iron deficiency and uraemia, can lead to poor sleep quality and increased daytime fatigue. Insomnia is also prevalent in CKD, particularly in patients requiring dialysis, with increased sleep latency and sleep fragmentation being reported. The cause of insomnia in CKD is multifactorial - poor sleep habits and frequent napping during dialysis, uraemia, medications and mood disorders have all been suggested as potential contributing factors. Sleep apnoea and CKD are also now recognized as having a bi-directional relationship. Sleep apnoea is a risk factor for accelerated progression of CKD, and fluid overload, which is associated with kidney failure, can lead to both obstructive and central sleep apnoea. The presence of obstructive sleep apnoea in CKD can exacerbate the already heightened cardiovascular morbidity and mortality in these patients, as well as leading to daytime fatigue and reduced quality of life. Increased awareness, timely diagnosis and appropriate therapeutic interventions are essential to reduce the negative impact of sleep disorders in patients with kidney disease.

Is kidney a new organ target in patients with obstructive sleep apnea? Research priorities in a rapidly evolving field

The bidirectional relationship between sleep disordered breathing and chronic kidney disease (CKD) has recently gained a lot of interest. Several lines of evidence suggest the high prevalence of coexistent obstructive sleep apnea (OSA) in patients with CKD and end-stage renal disease (ESRD). In addition, OSA seems to result in loss of kidney function in some patients, especially in those with cardio-metabolic comorbidities. Treatment of CKD/ESRD and OSA can alter the natural history of each other; still better phenotyping with selection of appropriate treatment approaches is urgently needed. The aim of this narrative review is to provide an update of recent studies on epidemiological associations, pathophysiological interactions, and management of patients with OSA and CKD or ESRD.

Obstructive sleep apnea and chronic kidney disease

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is highly prevalent in patients with chronic kidney disease (CKD). The relationship between OSA and CKD is likely to be bi-directional. On one hand, the presence of OSA leads to intermittent hypoxia, sympathetic nervous system activity, and hypertension, all of which may have deleterious effects on kidney function. On the other hand, in patients with end-stage renal disease (ESRD), intensification of renal replacement therapy has been shown to attenuate sleep apnea severity, suggesting that the renal disease itself contributes to the pathogenesis of OSA. The present review describes our current understanding of the bi-directional relationship between OSA and CKD.

RECENT FINDINGS

Studies suggest that the presence of OSA and nocturnal hypoxia may lead to worsening of kidney function. One potential mechanism is activation of the renin-angiotensin system by OSA, an effect which may be attenuated by CPAP therapy. In ESRD, fluid overload plays an important role in the pathogenesis of OSA and fluid removal by ultrafiltration leads to marked improvements in sleep apnea severity.

SUMMARY

OSA is associated with accelerated loss of kidney function. In patients with ESRD, fluid overload plays an important role in the pathogenesis of OSA.

Sleep breathing disorders: have we reached the tipping point?

Sleep medicine: a new approach http://ow.ly/qzVh30iVkWL.