Increased coated-platelet levels in chronic haemodialysis patients

Aim: To determine if levels of coated-platelets, which are potentially pro-thrombotic, are increased in end-stage renal disease patients on haemodialysis, a condition associated with high cardiovascular disease risk. Methods: In a cross-sectional observational study, coated-platelet levels were measured by flow cytometry in 25 end-stage renal failure haemodialysis patients and 25 controls without renal disease. Associations between coated-platelet levels and clinical and biochemical factors relevant to renal and cardiovascular disease were evaluated. Results: Mean +/- SD coated-platelet levels were higher in the dialysis group than in the control group (39.3 +/- 14.3% vs 30.9 +/- 10.3%, P = 0.02). The number of subjects with high coated-platelet levels (>40%) was larger in the dialysis than in the control group (13/25 vs 4/25, chi(2) test, P = 0.007). On univariate analysis, coated-platelet levels correlated with serum C-reactive protein levels in renal failure (r = 0.47, P = 0.02) and inversely with white cell count in the control group (r = -0.60, P = 0.001). Coated-platelet levels were higher in dialysis patients reporting alcohol abstinence than among those reporting 'social' drinking (44.3 +/- 12.6 vs 28.8 +/- 13.5%, P = 0.01). Age, gender, body weight, smoking, diabetes, lipid levels and lipid-lowering drugs were not associated with coated-platelet levels (all P > 0.05). Conclusion: Coated-platelet levels are increased in haemodialysis patients relative to subjects with normal renal function, and are related to inflammation and alcohol abstinence. Other vascular risk factors, such as smoking, lipids and diabetes, were not related to coated-platelet levels. Coated-platelets may be implicated in the increased thrombosis and vascular risk in end-stage renal disease.