Does neutrophyl to lymphocyte ratio really predict chronic kidney disease progression?

Chronic kidney disease (CKD) is an inflammatory process. In addition to increased morbidity and mortality, inflammation also contributes to the progression of CKD. Neutrophil/lymphocyte ratio (NLR) is a marker of inflammation. Some recent data suggest that NLR may predict the progression of CKD.

In this study, 5-year data of 740 patients with stage 2-4 CKD were reviewed retrospectively. Demographic data, NLR, CRP, albumin, the amount of proteinuria were recorded. At the beginning and the end of follow-up the glomerular filtration rate (GFR) and the annual GFR decline rate were calculated. Patients were divided to high and low NLR group according to median value of their baseline NLR. Reaching stage 5 CKD or initiation of renal replacement therapy was determined as end-point for follow-up.

The mean age was 62.8 ± 0.57 years, eGFR 40 ml/min/1.73 m², median NLR was 2.76. NLR increased as the CKD-stage increased. Mean follow-up time was 51.2 ± 30 months and 21.4% of patients reached the end-point. NLR was significantly increased at follow-up (from 3.22 to 5.68, p < 0.001). Annual GFR loss and baseline CRP were higher but baseline albumin and GFR were lower of patients with high NLR. The percent of patients reaching the end-point was not different between the groups with high and low baseline NLR. Kaplan Meier analysis showed that patients with high NLR had significantly lower mean renal survival (86.5 months) than patients with low NLR (105 months) (p < 0.001). In the Cox-regression analysis NLR was not an independent predictor in reaching the end-point but presence of diabetes mellitus, younger age and low baseline eGFR were found effective.

NLR is an indicator of inflammation in chronic kidney disease. It may not be an independent predictor of CKD progression except that the CKD is in a more advanced stage and reflects the associated inflammation. Classical risk factors such as DM and lower GFR are more powerful predictors of progression.