Anemia Increases Risk of End-Stage Kidney Disease in IgA Nephropathy

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An analysis from the 61st European Renal Association Congress is shedding light on the prevalence of anemia at biopsy and its impact on prognosis among patients with IgA nephropathy.

An analysis of more than 800 patients receiving care over nearly 2 decades, results of the study suggest reduced hemoglobin (Hb) was present in approximately 20% of patients with IgA nephropathy, with further analysis indicating presence was associated with an increased likelihood of having reduced serum albumin and reduced eGFR as well as a greater risk of progressing to end-stage kidney disease (ESKD).¹

“A low Hb level at the time of biopsy, even if subclinical, was an independent risk factor for the development of ESKD in patients with [IgA nephropathy]. Therefore, it is necessary to monitor Hb levels at the time of diagnosis and take proactive measures to reduce the risk of disease progression,” investigators wrote.¹

Although the community saw its first full approval for IgA nephropathy in late 2023, optimal management strategies for the rare nephrotic syndrome still represent a major research need within the field of nephrology. With this in mind, investigators from the Kyungpook National University Hospital, sought to clarify better the prevalence of anemia and its effect on prognosis among patients with IgA nephropathy.^1,2

The retrospective cohort study launched by investigators pooled data from patients with biopsy-proven IgA nephropathy who received care at the Kyungpook National University Hospital between January 2002 and December 2021. From the electronic medical record system, investigators obtained data on comorbidities, demographic variables, and laboratory indicators at the time of kidney biopsy.¹

The investigators initial inquiry yielded 952 patients, but 71 were eliminated because they were less than 17 years of age, 18 underwent a graft kidney biopsy, and 8 received a diagnosis of cancer prior to biopsy. In total, 855 patients were included in the study.¹

For the purpose of analysis, this cohort was stratified according to presence of anemia, which was defined as a Hb level of less than 13 g/dL in males and less than 12 g/dL in females. Among the 855 patients, 214 were classified as having anemia and 641 were classified as not having anemia.¹

The primary outcome of interest for the study were to evaluate the risk factors for anemia and to estimate the effects of anemia on the development of ESKD. Of note, risk factors for anemia were assessed using univariate and multivariate logistic regression analyses, whereas estimates of association with ESKD were estimated using Cox proportional hazard model.¹

Initial analysis revealed patients with anemia at biopsy had a significantly greater UPCR, reduced serum albumin levels, reduced eGFR, more severe interstitial fibrosis, and greater tubular atrophy than their counterparts without anemia. Further analysis revealed a Kaplan-Meier survival curve suggesting patients with anemia had worse renal survival than those without anemia.¹

Additionally, multivariable Cox analysis adjusted for age, eGFR, serum albumin, and UPCR showed that anemia was an independent risk for the progression to ESKD (Hazard Ratio [HR] 2.86, confidence interval [CI], 1.58 to 5.17; P = .001). In sex-specific analyses, only female patients with anemia experienced a significant increase in risk for ESKD (HR, 4.07; 95% CI, 1.53 to 10.8; P = .005).¹

References:

1. Kim KY, Park SH, Yoo J, et al. Anemia in patients with IgA nephropathy: an impact on the prognosis of IgA nephropathy. Abstract presented at 61st European Renal Association Congress. Stockholm, Sweden. May 23-26, 2024.
2. Brooks A. FDA awards full approval to Budesonide (Tarpeyo) in treatment of IGA nephropathy. HCP Live. December 20, 2023. Accessed May 27, 2024. https://www.hcplive.com/view/fda-awards-full-approval-to-budesonide-tarpeyo-in-treatment-of-iga-nephropathy.