Volume overload as a mechanism for obstructive sleep apnea in CKD?

The prevalence rate of sleep apnea in the hemodialysis (HD) patient population is >50% [1, 2] as compared to only 2–4% in the general population [3]. Not only does sleep apnea contribute to hypertension (HTN) and increased cardiovascular morbidity and mortality in the end-stage renal disease (ESRD) population, but it also significantly impairs their quality of life. However, large gaps in knowledge exist in our understanding of the potential mechanisms for increased sleep apnea in this vulnerable population. Traditional risk factors such as age and body mass index (BMI) do not fully account for the significant increased risk of sleep apnea in these patients [4]. As HTN and fluid overload occur almost universally in HD patients, it is possible that fluid retention may increase the risk of developing obstructive sleep apnea (OSA). If, indeed, fluid overload contributes to sleep apnea and poor sleep efficiency in HD patients, then the treatment of sleep apnea among those with ESRD could be targeted to improving volume control rather than using continuous positive airway pressure (CPAP) or an oral device, which many patients are unable to tolerate or comply with. In this issue of Nephrology Dialysis Transplantation, Elias et al. [5] addresses this important issue in their study evaluating the relationship of rostral fluid shift with OSA 1291