Neutrophil-to-lymphocyte ratio shows positive correlation with proteinuria in different stages of chronic kidney disease

Nifla S¹, Azra MAF¹, Asra MHF¹, Brammah RT², Karunaithas R¹

¹Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, University of Jaffna, Sri Lanka.

²Nephrology clinic, Teaching Hospital, Jaffna, Sri Lanka.

karunaithas@univ.jfn.ac.lk

Background: Chronic kidney disease (CKD) is a progressive disorder in which early detection and monitoring of disease progression are crucial in its treatment. Proteinuria determined by the protein-to-creatinine ratio (UPCR) is commonly used as a marker of severity monitoring during CKD; however, UPCR was found to be affected by muscle mass, urine tonicity, sex, age, nutritional status, and comorbid medical conditions. Recently, the neutrophil-to-lymphocyte ratio (NLR) was found to be correlated with proteinuria and proposed as a cost-effective marker for the prediction of CKD severity. Nonetheless, the correlation between NLR and proteinuria in different stages of CKD is not reported in the literature. The present study aimed to evaluate the correlation of NLR with proteinuria in stages 2-4 of CKD.

Methods: The ethical clearance for the study was obtained from the Ethics Review Committee, Faculty of Medicine, University of Jaffna, Sri Lanka. Blood and urine samples were collected from 85 randomly selected CKD patients who visited the Nephrology clinic at Teaching Hospital Jaffna with their consent and they were classified into different stages based on their estimated glomerular filtration rate (e-GFR) values. Participants' demographic and clinical characteristics and laboratory data were obtained from the patient's medical records. Total white blood cell and differential white blood cell counts were performed to determine the NLR. Furthermore, urine protein and creatinine were measured, and proteinuria was determined using protein creatinine ratio (UPCR). Spearman rank correlation analyses were performed using the Statistical Package for the Social Sciences version 16, and the p-value <0.05 was considered statistically significant.                                                                                                             

Results:  Amongst the participants, males were predominant (58.8%), with a mean age of 58.1. Most of the patients (28.2%) had multiple comorbidities, although hypertension (27.4%), glomerulonephritis (18.8%) and diabetes (10.6%) were the leading comorbidities associated with CKD. There were 17.64%, 18.82%, 29.41%, and 34.11% of patients in CKD stages II, IIIA, IIIB, and IV, respectively. The bivariate correlation analysis revealed that NLR was positively correlated with UPCR (r = 0.791, p < 0.0001) in CKD patients. Furthermore, the stage-wise correlation analysis indicated that NLR had a positive correlation with UPCR in different stages of CKD (Stage II; r= 0.267, P=0.336, Stage IIIA; r= 0.928, P < 0.0001, Stage IIIB; r= 0.782, P < 0.0001, Stage IV, r= 0.641, P < 0.0001). Notably, the correlation between NLR and UPCR in the late stages of CKD (IIIA, IIIB and IV) was statistically significant.

Conclusion: The findings indicated that NLR has a strong positive correlation with proteinuria in stages IIIA, IIIB, and IV of CKD; therefore, it could be used as a novel predictive marker for determining the severity of CKD. However, further large-scale studies are recommended to find the effect of genetic and demographic variations on NLR.

Keywords: Chronic kidney disease, Proteinuria, Neutrophil-Lymphocyte ratio.