Relationship between hemoglobin and renal tubular atrophy/interstitial fibrosis in patients with IgA nephropathy / 中华肾脏病杂志

ABSTRACT

Objective:To clarify the relationship between the hemoglobin level and renal tubular atrophy/interstitial fibrosis (T) in the Oxford stage of renal pathology in IgA nephropathy (IgAN) patients.Methods:Patients diagnosed with IgAN by renal biopsy from January 1 st 2010 to December 31 st 2015 in Shenzhen Second People's Hospital with complete laboratory and imaging data were retrospectively analyzed. Patients were divided into anemic group and non-anemic group. The relationship between hemoglobin level and renal tubular atrophy/interstitial fibrosis was determined by logistic regression analysis. The possible curve relationship between hemoglobin and renal tubular atrophy/interstitial fibrosis was analyzed by smooth curve fitting analysis. The diagnostic value of hemoglobin for renal tubular atrophy/interstitial fibrosis was analyzed by the receiver operating curve (ROC). Results:A total of 630 patients with IgAN were included in this study, 130 patients in the anemia group (20.63%) and 500 patients in the non-anemia group (79.37%). There was no statistically significant difference in age between the two groups, but the difference of the gender was statistically significant (male 35.38% vs 53.80%, χ2=10.740, P<0.001). Compared with the non-anemia group, the anemia group had a higher proportion of tubular atrophy/interstitial fibrosis ( χ2=62.586, P<0.001), higher 24 h urinary protein quantification ( Z=-6.082, P<0.001), and lower eGFR ( t=7.126, P<0.001). Multivariate logistic regression analysis showed that increasing hemoglobin level was an independent protective factor for reducing the risk of renal tubular atrophy/interstitial fibrosis ( OR=0.973, 95% CI 0.958-0.987, P<0.001). Smooth curve fitting analysis showed that there was a linear negative correlation between hemoglobin and tubular atrophy/interstitial fibrosis. The ROC curve suggested that the best threshold of hemoglobin was 120.5 g/L when renal tubular atrophy/interstitial fibrosis occurred. That was, when hemoglobin was above 120.5 g/L, the severity level of renal tubular atrophy interstitial fibrosis might be reduced. Conclusion:The incidence of renal tubular atrophy/interstitial fibrosis is higher in IgAN patients with anemia, and hemoglobin>120.5 g/L may reduce the risk of tubular atrophy/interstitial fibrosis.