Plasma creatine kinase and all-cause mortality in patients on peritoneal dialysis: a multi-center retrospective study

Abstract

Background Higher plasma creatine kinase (CK) values are associated with the failure of antihypertensive treatment. However, an association between CK and all-cause mortality in peritoneal dialysis (PD) patients has received little attention.Methods In this retrospective multicenter study, 1382 incident PD patients with baseline CK values were enrolled from November 1, 2005, to February 28, 2017. All patients with oral statins were excluded and then were divided into four groups according to quartile range [Quartile 1 (<60 U/L), Quartile 2 (60-100 U/L), Quartile 3 (101-179 U/L), and Quartile 4 (>179 U/L)]. The primary endpoint was all-cause mortality. The association between plasma CK values and all-cause mortality was assessed with Cox regression and the Fine and Gray models.Results Of 1382 patients 298 (21.6%) patients died during a median 35-month (interquartile range=19-54 months) follow-up period. Patients in Quartile 4 were older (P<0.001), likely to be male (P<0.001), had a higher prevalence of diabetes (P=0.002), and a history of cardiovascular disease (P=0.005), and higher values of Charlson comorbidity index (P=0.031). All-cause mortality incidence was a significant difference among the four Quartiles (Quartile 1, 16.2%; Quartile 2, 22.2%; Quartile 3, 23.8%; Quartile 4, 24.1%; P=0.043). Cumulative all-cause mortality in the Quartile 4 was significantly higher compared with other groups (Log Rank=10.55, P=0.015). After adjusting for confounding factors, the highest CK quartile had a hazard ratio (HR) for all-cause mortality of 1.75 [95% confidence interval (CI) 1.34-3.20, P=0.041]. With kidney transplantation or hemodialysis as a competing risk, the Quartile 4 had an HR for all-cause mortality of 1.66 (95%CI 1.30-3.41, P=0.044), after adjusting for confounding factors.Conclusions Higher plasma CK levels at the commencement of PD may be a valuable biomarker for predicting the development of all-cause mortality in PD patients.