Platelet index levels and cardiovascular mortality in incident peritoneal dialysis patients: a cohort study

Prior studies have shown that the levels of some platelet (PLT) indices were associated with mortality in patients undergoing hemodialysis. We aimed to investigate whether the changes in PLT indices associated with mortality in patients on peritoneal dialysis (PD). A single-center, retrospective observational cohort study was conducted in incident PD patients from 1 January 2006 to 31 December 2012, and followed up until 31 December 2014. Cox proportional hazard models were used to examine the relationships between the levels of PLT indices including PLT, plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (PLCR), and mortality. Of 1324 patients, 276 (20.8%) died during follow-up (median, 37; IQR, 3-107.4 months), among which 134 were due to cardiovascular diseases (CVD). The highest tertile of PLT levels at baseline was associated with increased risk for cardiovascular mortality after adjustment for demographic, clinical characteristics, and laboratory variables (hazard ratio [HR]:1.93; 95% confidence interval [CI]: 1.16-3.20). The similar treads were also observed in the middle and the highest tertile of the PCT level (HR: 1.68, 95%CI: 1.00-2.81 and HR: 1.89, 95%CI: 1.14-3.14, respectively). In addition, the highest tertile of PCT was associated with increased all-cause mortality (HR: 1.41, 95%CI: 1.01-1.96). However, none of the associations in MPV, PDW, and PLCR analyses reached statistical significance (HR: 0.71, 95%CI: 0.43-1.16; HR: 0.72, 95%CI: 0.45-1.18 and HR: 0.74, 95%CI: 0.46-1.19, respectively). These results suggest that higher PLT and PCT may be associated with higher risk for cardiovascular mortality in incident PD patients. Additional studies are needed to investigate whether correction of these two PLT indices reduces the risk.