Relationship between blood neutrophil-lymphocyte ratio and renal tubular atrophy/interstitial fibrosis in IgA nephropathy patients

Background: The study aimed to explore the relationship between neutrophil-lymphocyte ratio(NLR) in peripheral blood and renal tubular atrophy/interstitial fibrosis and to evaluate the clinical significance of NLR in IgA nephropathy (IgAN) patients. Methods: A Total of 263 IgAN patients were included. The participants were categorized into four groups based on quartile of NLR. The clinical data, pathological features, and 2-year renal survival rates were compared among the four groups. The independent factors affecting renal tubular atrophy/interstitial fibrosis in IgAN were determined by multivariate linear regression analysis. Results: The percentage of renal tubular atrophy/interstitial fibrosis increased with the increase of NLR level (p=0.003). The tubular atrophy/interstitial fibrosis score T1 and T2 in Group Q4 was 40%, which was higher than that of other groups, especially Group Q1 (22.73%, p=0.033) and Group Q3 (22.39%, p=0.029). NLR [beta=1.230, 95%CI (0.081, 2.379), p=0.036] might be an independent factor affecting renal tubular atrophy/interstitial fibrosis in IgAN. The area under curve predicted by NLR was 0.596 (95%CI 0.534 similar to 0.656, p=0.007) with the specificity 88.24% and the optimal critical value of NLR 3.25. Fourteen patients progressed to end-stage renal disease within 2 years, and the 2-year survival rate of kidney was 93.49%. The renal survival rate in Group Q4 was 87.04%, lower than that in other three groups, especially Group Q1 (98.11%, p=0.029). Conclusion: NLR was correlated with the level of renal tubular atrophy/interstitial fibrosis and might be a significant factor for predicting the prognosis in the IgAN. Background: IgA nephropathy (IgAN) is an important cause of the end stage renal disease (ESRD). The study aimed to explore the relationship between neutrophil-lymphocyte ratio (NLR) in peripheral blood and renal tubular atrophy/interstitial fibrosis, and to evaluate the clinical significance of NLR in IgA nephropathy (IgAN) patients. Methods: Total 263 IgAN patients confirmed by renal biopsy pathology were included from January 2013 to May 2018 in Ningbo Hwamei Hospital, University of Chinese Academy of Sciences. The peripheral blood samples were taken from these participants and the NLR was analyzed. The participants were categorized into four groups based on the median and upper and lower quartile of NLR, which were Group Q1 (NLR<1.64), Group Q2 (1.64 <= NLR<2.19), Group Q3 (2.19 <= NLR<3.00), and Group Q4 (NLR >= 3.00), respectively. The clinical data and pathological features were compared among four groups. The independent factors affecting renal tubular atrophy/interstitial fibrosis in IgAN were determined by multivariate linear regression analysis. The diagnostic ability of NLR for renal tubular atrophy/interstitial fibrosis was evaluated by the area under receiver operating characteristic curve (AUC). The 2-year renal survival rates were compared among the four groups. Results: The levels of white blood cell count, neutrophil count, highly sensitive C-reactive protein, and the percentage of renal tubular atrophy/interstitial fibrosis were increased while lymphocyte count and estimated glomerular filtration rate were decreased with the increase of NLR level (P < 0.05). The percentage of tubular atrophy/interstitial fibrosis 26%-50% (T1) and >50% (T2) in Group Q4 was 40%, which was higher than that of other groups, especially Group Q1 (22.73%) and Group Q3 (22.39%), with significant difference (P < 0.05). NLR [beta = 1.230, 95%CI (0.081, 2.379), P = 0.036] might be an independent factor affecting renal tubular atrophy/interstitial fibrosis in IgAN according to multivariate linear regression analysis results. The AUC predicted by NLR was 0.596 (95%CI 0.534 similar to 0.656, P = 0.007) with the specificity 88.24%, the sensitivity 30.00% and the optimal critical value of NLR 3.25. Fourteen patients progressed to end-stage renal disease within 2 years; and the 2-year survival rate of kidney was 93.49%. The renal survival rate in Group Q4 was 87.04%, lower than that in other three groups, especially Group Q1 (98.11%), with significant difference (P < 0.05). Conclusion: NLR was correlated with the level of renal tubular atrophy/interstitial fibrosis and might be an significant factor for predicting the prognosis in IgAN.