Relative lymphocyte count as a marker of progression of chronic kidney disease

Although low relative lymphocyte count (RLC) is associated with poor outcomes in patients with chronic kidney disease (CKD), the relationship between low RLC and progression of CKD is poorly defined. The aim of this study was to determine the association between low RLC and the progression of CKD. Between January 2003 and December 2009, 288 CKD patients were analyzed. RLC was calculated as the ratio between lymphocyte and total white blood cell counts. The median RLC was 29.1 % [interquartile range (IQR) 24.1-34.1]. When the patients were compared according to a level below or above the median value for RLC, the rate of CKD progression to end-stage renal disease (ESRD) was greater in patients with low RLC count than in patients with high RLC (48 vs. 25 %, p < 0.001) during the median follow-up of 5.5 years (IQR 3.5-7.6). The variables found to be predictive of progression to the ESRD included younger age, smoking, diabetes, higher systolic blood pressure, no use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs), lower hemoglobin and serum albumin levels, higher low-density lipoprotein cholesterol concentration, presence of proteinuria, and low RLC in the univariate Cox proportional hazards regression analysis. However, after adjustment, younger age, male, higher systolic blood pressure, no use of ACEIs or ARBs, lower hemoglobin and serum albumin concentrations, higher proteinuria, and lower RLC were significantly associated with progression to ESRD in multivariate analysis. Low RLC is independently associated with increased rate of progression in patients with CKD.