Elevated serum interleukin-18 levels might reflect the high risk of hospitalization in patients on peritoneal dialysis

Background: Interleukin (IL)-18 is a potent pro-inflammatory cytokine and plays a central role in atherosclerotic plaque rupture and accelerates atherosclerosis. Aim: The aim of this study was to determine serum IL-18 levels in patients on peritoneal dialysis (PD) and to assess their relationship with hospitalization. Methods: Forty-three PD patients and 20 healthy individuals were enrolled in this study. We investigated the relationship of the serum concentrations of IL-18 and other well-established atherosclerotic markers, such as asymmetric dimethylarginine (ADMA). Hospitalization data from over a 18-month period were prospectively obtained on all 43 PD patients. Classic factors were entered into a Cox regression model to predict first hospitalization. Results: The serum levels of IL-18 in patients on PD were significantly higher than those of healthy individuals (228.5 ± 140.3 pg/mL vs 154.8 ± 44.7 pg/mL, P < 0.05, respectively). Furthermore, serum IL-18 levels showed a positive correlation with duration of PD, serum β2 microglobulin and serum ADMA levels. Mean serum levels of IL-18 were significantly higher among patients who had experienced at least one hospitalization than those who had not (279.9 ± 164.3 vs 158.5 ± 43.9 pg/mL, P = 0.0426). Furthermore, the relative risk for first hospitalization for each increase in IL-18 (pg/mL) levels was associated with a 1.182 (95% confidence interval, 1.012-1.364; P = 0.0071) increase in the risk for future hospitalization events. Conclusion: The present study suggests the elevated serum IL-18 levels might increase the risk for future hospitalization in patients on PD.