Platelet and Monocyte Activity Markers and Mortality in Patients with End-Stage Renal Disease

BACKGROUND The association of platelet and monocyte activity markers with long-term mortality was assessed in hemodialysis (HD) patients. METHODS In 41 HD patients (25 male, 16 female), surface expression of CD40L and CD62P on platelets, tissue factor (TF) binding on monocytes, and platelet-monocyte aggregates were measured by flow cytometry. Plasma levels of MCP-1, IL-6, TNFα, and soluble CD40L were analyzed by enzyme linked immunosorbent assay. Cox proportional hazard regression analyses and Kaplan-Meier curve were calculated. The predefined endpoint was all-cause mortality. RESULTS The study follow-up was 11.54 years. Thirty-one patients (75.6%) died within the study period. Mean patient survival after study inclusion was 5.45 +/- 4.24 years. TF on monocytes above the median of the study population was significantly and independently associated with total mortality (HR (95% CI) 3.45 (1.32 - 9.07); p = 0.01). Cumulative mortality in patients with TF on monocytes above median was significantly higher compared to pa-tients with TF on monocytes below median value (log rank p < 0.01). Platelet-monocyte aggregates, the expression of CD40L and CD62P on platelets, and plasma levels of sCD40L, IL-6, MCP-1, and TNFα were not significantly correlated with mortality. CONCLUSIONS The present study confirms a high mortality in ESRD patients. TF binding on monocytes was significantly correlated with increased mortality and may identify a subgroup of patients at higher risk.