Relationship between sleep complaints and proinflammatory cytokines in haemodialysis patients

Background: Sleep complaints are common in end-stage renal disease. We aimed to investigate the relationship between sleep-related complaints and inflammatory cytokines in haemodialysis (HD) patients, and also the effects of HD on sleep patterns and cytokine levels. Methods: Predialysis serum interleukin-1beta (IL-1 beta), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-alpha) levels in nine patients with sleep complaints were compared with those of nine patients without sleep complaints and nine healthy controls. Patients with sleep complaints underwent polysomnography the night after HD and the following night. Results: Patients with sleep complaints had significantly higher predialysis IL-1 beta levels compared with those without and healthy controls (P = 0.004 and P = 0.000, respectively). They also had higher predialysis IL-6 and TNF-alpha levels than those without sleep complaints; however, the difference was not significant. Patients without sleep complaints had higher mean IL-6 and TNF-alpha and similar mean IL-1 beta levels compared with healthy controls (P = 0.001, P = 0.024, P = 0.26, respectively). Obstructive sleep apnoea syndrome (OSAS) was found in six out of nine (66%) patients with sleep complaints. Sleep architecture and cytokine levels did not differ between the two nights. The mean serum IL-1 beta, IL-6 and TNF-alpha levels did not differ in the pre- and post-polysomnographic samples. There was no correlation between IL-1 beta, IL-6 or TNF-alpha levels and the apnoea-hypopnoea index. Conclusions: Proinflammatory cytokines, IL-1 beta in particular, might be associated with sleep complaints in HD patients. OSAS is not uncommon in HD patients with sleep-related complaints and sleep architecture does not appear to be effected by the HD procedure itself.