38 Both studies support the hypothesis that improvements in solute clearance

and extracellular fluid volume control during sleep can improve or possibly cure SA. Additionally, case reports have described renal transplantation as a cure for SA presumably due to the elimination of the uremic milieu.39,40 Given the high prevalence of SA in the ESRD population, the clinician STA-9090 should maintain a low threshold for obtaining a polysomnography with sleep study in patients who complain of poor sleep quality or daytime somnolence. The higher rate of central SA warrants early testing for sleep disturbances. Positive airway devices may be more efficacious than lifestyle modifications such as weight loss because dialysis patients may not have the classic obstructive apnoea features. Continuous positive airway pressure treatment in ESRD has been shown to improve nocturnal oxygenation and daytime alertness in a small study population.41 Once the diagnosis of SA is made, the physician should identify modifiable risk factors. A careful medication history should be performed and attempts should be made to discontinue any

medications that could increase SA risk or worsen the disease. Nocturnal dialysis in the form of HD or night-time PD may be an option if available to improve night-time volume and clearance. Finally, renal transplantation is a goal for many dialysis patients and may represent a possible cure for SA in a subset of patients. Although SA in ESRD is eltoprazine well described, few studies have evaluated SA prevalence in early CKD or patients not yet on PD0325901 dialysis. Markou et al.22 performed sleep studies on 35 patients with creatinine clearance less than 40 mL/min but not on dialysis. SA was present in 54.3% of these patients suggesting that it is also highly prevalent in CKD patients far removed from renal replacement therapy. Another small study by Kimmel et al.12 found SA in all six of the CKD patients that underwent polysomnography. Sleep apnoea prevalence in early CKD was evaluated in one study from large integrated health system.66 Using International Statistical Classification of Diseases and Related Health Problems-9 coding and device

coding for positive airway pressure devices, the study found a 20–40% greater risk of SA in patients with estimated glomerular filtration rate in the range 15–89 mL/min per 1.73 m2 (CKD stages 2–4). These differences were sustained after controlling for possible confounders including diabetes, heart failure and hypertension. While the risk of SA was not increased in patients with lower levels of renal function in this study, those patients had disproportionately higher rates of death and progression to dialysis during the evaluation period and thus were not included in the study cohort. The CKD is a progressive disease that results in higher mortality with advancing stages42 and concurrent SA may lead to greater mortality when the two diseases coexist.