Clinical and pathological factors of renal anaemia in patients with IgA nephropathy in Chinese adults: a cross-sectional study

Abstract

Objective: Few studies with large sample populations concerning renal anaemia and IgA nephropathy have been reported worldwide. The purpose of this cross-sectional study was to examine the clinical and pathological characteristics and influencing factors associated with renal anaemia in patients with IgA nephropathy, which is the most common aetiology of chronic kidney disease.

Methods: A total of 462 hospitalised patients with IgA nephropathy confirmed by renal biopsy who met the inclusion criteria were consecutively recruited from January 2014 to January 2016. Their general information, routine blood test results, blood chemistries, estimated glomerular filtration rates (eGFRs) and renal pathologies were collected. The Oxford classification was used to characterise the renal pathologies. Univariable and multivariate logistic regression models were used to analyse the influencing factors of anaemia associated with IgA nephropathy.

Results: The incidence of renal anaemia was 28.5% (132/462 patients) in our study (21.3% in males and 38.9% in females). The anaemia type was primarily normocytic and normochromic. The rate of anaemia in patients with eGFR values of 30-59 mL/min/1.73 m² was higher than that in patients with an eGFR >60 mL/min/1.73 m² (42.9% vs 17.8%, p<0.001). Notably, in the group with eGFR values <15 mL/min/1.73 m², the anaemia rate was 100%. Logistic regression analysis showed that factors affecting anaemia in patients with IgA nephropathy included being female (OR 3.02, 95% CI 1.76 to 5.17), low albumin levels (OR 0.87, 95% CI 0.82 to 0.93), reduced eGFR values (OR 0.98, 95% CI 0.97 to 0.99) and renal tubulointerstitial lesions >50% (OR 2.57, 95% CI 1.22 to 5.40).

Conclusions: The female sex, hypoalbuminaemia, reduced eGFR levels and severe renal tubulointerstitial lesions were correlated with renal anaemia in patients with IgA nephropathy. These results provide new insight into our understanding of anaemia in IgA nephropathy and may improve the management and treatment of clinical renal anaemia.

Keywords: iga nephropathy; renal anaemia; renal tubulointerstitial lesions.

Figure 1

Flow chart showing the study design. AKI, acute kidney injury; BMI, body mass index.

Figure 2

The rate of anaemia and non-anaemia in patients with different eGFR levels. Comparison of the rate of anaemia at different eGFR levels: *P<0.05 compared with anaemic patients with an eGFR >60 mL/min/1.73 m²; ^#P<0.05 compared with anaemic patients with an eGFR of 30–59 mL/min/1.73 m². eGFR, estimated glomerular filtration rate.