Sleep disorders: Serious threats among kidney transplant recipients

In patients with chronic kidney disease (CKD) and kidney transplant recipients who continue to have some degree of CKD, the prevalence of sleep-related disorders is very high. Common sleep disorders in both groups include insomnia, sleep-disordered breathing (SDB), restless legs syndrome (RLS), excessive daytime sleepiness (EDS), and others. Depending on the kidney graft function, some patients see sleep disorders resolve after kidney transplantation, while others continue to have persistent sleep disorders or develop new ones. Kidney transplant recipients (KTRs) are unique patients due to the presence of a single kidney, the use of immunosuppressive medications, and other comorbidities including obesity, a high risk of cardiovascular disease, malignancy, and the anxiety of losing their allograft. All of these factors contribute to the risk for sleep disorders. CKD and sleep disorders have a bidirectional relationship; that is, CKD may increase the risk of sleep disorders and sleep disorders may increase the risk of CKD. Obstructive sleep apnea (OSA) is the most common form of SDB and is known to alter renal hemodynamics. OSA leads to hypoxemia and sleeps fragmentation, which activates the sympathetic nervous system. This activates the renin-angiotensin-aldosterone system and ultimately alters cardiovascular hemodynamics. Sleep disorders may have deleterious effects on the kidney allograft and proper screening and management are important for both graft and patient survival.