Higher plasma interleukin-18 levels associated with poor quality of sleep in peritoneal dialysis patients

Background. Sleep disorders are prevalent in patients with end-stage renal disease. Increasing evidence suggests that cytokines are involved in the regulation of sleep and wakefulness. The purpose of this study was to examine the relationship between quality of sleep and plasma interleukin-18 levels in peritoneal dialysis patients. Methods. Plasma interleukin-18 levels were determined by the enzyme-linked immunosorbent assay (ELISA) methodology in 57 peritoneal dialysis patients. Quality of sleep was measured using the Pittsburgh Sleep Quality Index. Demographic and routine laboratory data were recorded. Results. In our cohort, the poor sleepers had higher plasma interleukin-18 levels (559.16 +/- 261.22 pg/ml vs 397.49 +/- 191.81 pg/ml, P = 0.01). The plasma interleukin-18 level was positively correlated with the Pittsburgh Sleep Quality Index score (r = 0.286, P = 0.031), that is, there was a positive association between higher plasma interleukin-18 levels and poorer quality of sleep. Conclusion. This study demonstrates that interleukin-18 may be involved in sleep disorders in end-stage renal disease patients. Higher plasma interleukin-18 levels are associated with poorer quality of sleep in peritoneal dialysis patients. Whether a cause-and-effect relationship exists between interleukin-18 and quality of sleep deserves further study.