Neutrophil-to-lymphocyte ratio as an independent inflammatory indicator of poor prognosis in IgA nephropathy.

Abstract Background IgA nephropathy (IgAN) is a chronic immuno-inflammatory progressive disease. Several systemic inflammatory indicators, mainly the neutrophil-to-lymphocyte ratio (NLR), are regarded as valuable markers for many diseases, such as IgA vasculitis and chronic kidney disease. Here, we investigated multiple peripheral blood indicators in a large IgAN registry with regular follow-up to evaluate their effects on IgAN phenotypes and progression. Methods Totally, 1151 IgAN patients with regular follow-up, and 251 healthy volunteers were enrolled. Complete blood count test results, including counts of white blood cells (WBC), neutrophils (NE), lymphocyte (LY), and platelets (PLT), were collected from medical records. Then, NLR and PLR were calculated. Results IgAN patients presented with increased WBC, NE, NLR and PLR levels and decreased LY levels compared with controls. In univariate survival analysis, WBC, NE and NLR showed significant associations with IgAN progression, and NLR had a higher area under the ROC curves than NE and WBC. When adjusted for well-known risk factors, NLR remained an independent risk factor for poor renal outcome in IgAN patients and performed better than NE. By using NLR 2.40 as cutoff point, IgAN patients were divided into two groups. IgAN patients in the high NLR group presented with lower eGFR, higher proteinuria, higher incidence of hypertension, and more severe pathological lesions, as well as lower event-free renal survival rate. Conclusions We found patients with IgAN had elevated NLR levels than healthy controls, and the easily available NLR in clinical practice could serve as an independent risk factor for IgAN progression.