J-shaped association of platelet-to-lymphocyte ratio with 5-year mortality among patients with chronic kidney disease in a prospective cohort study

Purpose To examine whether platelet-to-lymphocyte ratio (PLR) is associated with 5-year mortality in patients with chronic kidney disease (CKD), we performed this study using data from the National Health and Nutrition Examination Survey (NHANES) through 1999 to 2006. Methods 3285 patients with CKD stage 1-5 were included. Patients' baseline characteristics were collected. Cox proportional hazards models were used to investigate the association of PLR with 5-year mortality including all-cause and cardiovascular mortality. Subgroup analysis was performed. Results Within 5 years following the date of the NHANES 1999 to 2006 survey participation, 655 (19.94%) deaths were recorded and 207 patients died from cardiovascular disease. A J-shaped association between PLR and 5-year mortality was observed. In adjusted model 2, the elevated PLRZ-score was not significantly associated with a decreased 5-year all-cause mortality risk (HR: 0.44, 95% CI: 0.16-1.22) when PLRZ-score < - 0.91 whereas the elevated PLRZ-score was significantly associated with an increased 5-year all-cause mortality risk (HR: 1.09, 95% CI: 1.01-1.17) when PLRZ-score >= - 0.91. In adjusted model 2, neither the elevated PLRZ-score was significantly associated with a decreased 5-year cardiovascular mortality risk (HR: 0.85, 95% CI: 0.36-2.04) when PLRZ-score < - 0.47 nor the elevated PLRZ-score was significantly associated with an increased 5-year cardiovascular mortality risk (HR: 1.12, 95% CI: 0.93-1.34) when PLRZ-score >= - 0.47. Conclusion The elevated PLR is independently associated with an increased 5-year all-cause mortality risk among patients with CKD stage 1-5 when PLR >= 83.18, indicating that PLR might be a potential biomarker to predict 5-year all-cause mortality in CKD patients.