Sleep disorders: a systematic review of an emerging major clinical issue in renal patients

The prevalence of sleep disorders is significantly higher (up to 80%) in patients with chronic uremia compared to the general population. Sleep disorders appear even in the early stages of chronic kidney disease. These disturbances are complex, including difficulties in falling asleep and awakening, interrupted sleep, nightmares, restless legs syndrome, sleep apnea syndrome, etc. There are still disagreements on the major etiological factors of sleep disorders in the uremic patient. Older age, long dialysis vintage, alcohol and tobacco abuse and, particularly, the presence of significant comorbidities are major determinants of sleep disorders in dialysis patients. Proper assessment of sleep disorders in the renal population is still under investigation; recent studies have mostly addressed patients' perception based on questionnaires. More precise polysomnographic assessments are less studied in renal patients. Sleep disorders significantly affect quality of life in dialysis patients. An accurate and early identification of such disturbances would lead to a significant improvement in quality of life, and probably also in outcome, in uremic patients. Sleep apnea syndrome is extremely frequent in dialysis patients, with obvious consequences for cardiovascular morbidity and mortality. Proper diagnosis and therapy of sleep apnea syndrome could significantly reduce cardiovascular risk. Although sleep quality improves after renal transplantation, allograft recipients still have significantly more sleep disorders than healthy individuals. Here, we review recent data on sleep disturbances in renal patients, focusing on the end-stage renal disease patient treated by dialysis.