Sleep disordered breathing in patients with chronic kidney disease.

The prevalence of sleep-disordered breathing (SDB) in the advanced chronic kidney disease (CKD) patient population has been estimated to be more than 50 per cent. SDB is associated with episodic upper airway obstruction or cessation of breathing during sleep leading to repetitive episodes of hypoxaemia, hypercapnia, and sleep fragmentation, activation of the sympathetic nervous system, endothelial dysfunction, oxidative stress, and inflammation. Clinical consequences of this disorder may include excessive daytime sleepiness, depressed mood, cognitive impairment, hypertension, as well as increased risk for cardiovascular disease and metabolic dysregulation. SDB may also contribute substantially to the daytime sleepiness, poor quality of life, and high rate of cardiovascular disease in CKD patients. Although the causal links between CKD and SDB remain speculative, there are multiple factors related to fluid overload and azotaemia that may contribute to the increased propensity to SDB. Renal transplantation, nocturnal automated peritoneal dialysis and nocturnal haemodialysis have been found to be associated with a reduction in the severity of SDB when compared to conventional forms of dialysis. Nocturnal dialysis modalities may facilitate further understanding of the pathophysiology of SDB as well as provide therapeutic alternatives for patients with both kidney failure and SDB. SDB is an important but often overlooked public health problem in the CKD patient population. Early diagnosis and treatment of SDB may provide better quality of life and attenuate the cardiovascular risk of morbidity and mortality in these patients.