Sleep Apnea as a Cardiorenal Risk Factor in CKD and Renal Transplant Patients

Chronic kidney disease (CKD) is a public health priority of increasing concern worldwide. Sleep apnea (SA) of moderate-to-severe degree has a 3-9% prevalence in women and 10-17% in men in the general population.

In CKD patients, the prevalence of SA parallels the decline of the GFR being 27% in CKD patients with a GFR of >60 mL/min/1.73 m2 and 57% in patients with end-stage kidney disease (ESKD). In the early CKD stages, fluid overload is probably the sole risk factor for SA in this population. At more severe CKD stages, disturbed central and peripheral chemosensitivity and the accumulation of uremic toxins might contribute to SA. Still, there is no direct evidence supporting this hypothesis in human studies. Observational studies coherently show that SA is a risk factor for CKD incidence and CKD progression as well as for cardiovascular disease and death in this population. However, there is no randomized clinical trial testing continuous positive airway pressure or other interventions documenting that attenuation of SA may have a favorable effect on renal and cardiovascular outcomes in CKD and ESKD patients. However, most likely, the causal nature of the association between SA and cardiorenal outcomes remains unproven. Renal transplantation is the most effective treatment of SA in patients with ESKD, but this disturbance re-emerges on long-term observation in this population. However, after renal transplantation, SA does not seem to be a predictor of adverse health outcomes.