Association of absolute lymphocyte count, neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios with mortality in chronic hemodialysis patients: a retrospective single-center cohort study

Objective Classical cardiovascular risk factors are not so predictive of survival in haemodialysis. Inflammation and malnutrition are the main predictors of mortality in haemodialysis population. As markers of inflammation, total white blood cell count, absolute neutrophil count and to a lesser degree lymphocyte count are associated with adverse cardiovascular outcomes in non-end stage renal disease population and with all-cause mortality in normal and haemodialysis population. This study explores the associations of three markers of inflammation (absolute lymphocyte count, neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios) with mortality in haemodialysis, taking into account additional confounding risk factors of inflammation and malnutrition for patient death. Methods Complete follow up data from 575 out of a total study population of 686 patients receiving maintenance haemodialysis in our centre Universitair Ziekenhuis Brussel from January 1rst 1998 to December 31rst 2011, were collected: age, gender, weight, medical history and laboratory tests (haematocrit, albumin, creatinine, potassium, calcium, phosphorus, bicarbonate, ferritin, CRP, transferrin saturation and differential WBC count) were retrieved. These data were merged with outcome data extracted from the NBVN registry. Association of absolute lymphocyte count, neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios with mortality was evaluated using Kaplan Meier and Cox hazard regression for confounding factors. Results Serum albumin emerged as the strongest risk factor for mortality. A higher absolute lymphocyte count was associated with lower mortality (p < 0.0001). High neutrophil-to-lymphocyte ratio was associated with higher mortality (p < 0.0001). A multivariate Cox hazard regression analysis showed similar results. The association between platelet-to-lymphocyte ratio and mortality was less strong (p=0.002 for Kaplan Meier curve and not significant for hazard regression). Conclusion Increased absolute lymphocyte count and neutrophil-to-lymphocyte ratio are respectively strongly associated with reduced and higher mortality, independently of confounding factors of nutrition (albumine) and inflammation (CRP). An increased neutrophil-to-lymphocyte ratio and a reduced lymphocyte count are independent predictors of higher mortality in haemodialysis patients.