Influences of renal anemia on the pathology of IgA nephropathy: a study based on propensity score matching

Objective This study aims to investigate the influences of renal anemia on the pathogenesis of IgA nephropathy using propensity score matching (PSM). Methods Renal biopsies from 462 patients with IgA nephropathy were enrolled in this study. PSM was used to balance intergroup covariates, and matching results were verified using a dot-plot of standardized mean differences and histograms of the propensity score distribution and distance distribution. The matched data were used to analyze the impact of renal anemia on the pathological indicators of IgA nephropathy by logistic regression. Results A total of 132 pairs of patients from the renal anemia group and the non-renal anemia group were matched by PSM; after matching, the standard deviations of 13 covariates were within 0.25. Multivariate logistic regression results suggested that the CKD4-5 stage of IgA nephropathy and tubular atrophy/interstitial fibrosis >50% were independent risk factors for renal anemia. Conclusions Via PSM, we demonstrated that decreased eGFR and severe tubular atrophy/interstitial fibrosis are correlated with renal anemia in IgA nephropathy. In clinical practice, renal anemia in patients with IgA nephropathy of CKD3 stage or above should be closely monitored and managed.