Nutritional Scores May Aid ESRD Risk Stratification in IgA Nephropathy

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Nutritional indexes may be useful tools for determining IgA nephropathy (IgAN) severity and identifying individuals at risk of progressing to end-stage renal disease (ESRD), according to findings from a recent study.¹

Results suggest a notable correlation between controlling nutritional status (CONUT) score, geriatric nutritional risk index (GNRI), and prognostic nutritional index (PNI) with the severity of crescents in patients with IgAN. Although PNI and GNRI were significantly reduced in patients with IgAN who developed ESRD, only GNRI emerged as a predictor of ESRD in multivariable analysis.¹

“Assessing nutritional status has become a focal point in enhancing disease management, particularly in renal diseases,” Mindan Sun, a professor in the department of nephrology at Jilin University in China, and colleagues wrote.¹ “Despite this, a unanimous standard for nutritional evaluation in renal conditions is lacking.”

A leading cause of glomerulonephritis and renal failure, IgAN typically progresses gradually, but estimates project between 20% and 50% of affected patients develop ESRD within 20 years of diagnosis. The clinical course of IgAN varies from patient to patient, presenting a notable difficulty in disease management and underscoring the need for prognostic tools to identify patients at the greatest risk of progressing to kidney failure.²

To assess the association between nutritional indexes and renal function in patients with IgAN, investigators conducted a retrospective review of adults who underwent renal biopsy at the First Hospital of Jilin University between January 2010 and October 2022 and were diagnosed with IgAN. Out of an initial 1077 patients, 341 were excluded due to eGFR (CKD-EPI) <15 mL/min/1.73 m2; the presence of autoimmune diseases; secondary IgAN conditions; acute infectious diseases or cancer; and incomplete or absent follow-up data.¹

In total, 736 patients were enrolled in the study. Among the cohort, the median age was 36 years and the majority (50.14%) of participants were male.¹

Investigators reviewed patients’ clinical and laboratory data and calculated 4 nutritional indexes: CONUT score, GNRI, body mass index (BMI), and PNI. The CONUT score was derived using a formula based on total cholesterol score, lymphocyte count score, and serum albumin score. GNRI was computed as (1.519 × serum albumin (g/dL)) + (41.7 × weight (kg)/ideal body weight (kg)), where the ideal weight was calculated as [height (m)]2 multiplied by 22. BMI was determined by weight (kg) divided by height (m) squared, while PNI was calculated as serum albumin (g/L) + 0.005 × blood lymphocyte count (/mm3).¹

During a median follow-up of 26 months, 80 (10.87%) patients were identified as having ESRD. Investigators called attention to significant disparities in nutritional indexes between the groups, particularly reflected in markedly reduced values of PNI (median 41.90 vs 46.30; P <.001) and GNRI (median 91.84 vs. 98.94; P <.001) among patients with ESRD.¹

Comparison of the 4 nutritional indexes across the MEST-C classification showed similar trends between PNI, GNRI, and CONUT scores for cellular/fibro cellular crescent classification. Specifically, investigators noted patients classified as C2 exhibited lower PNI and GNRI scores compared to those in C0 and C1, whereas the CONUT score showed the opposite trend.¹

Among the 4 nutritional indexes analyzed, PNI (AUC, 0.627; sensitivity 71.6%, specificity 57.5; 95% CI, 0.560–0.693; P <.001), GNRI (AUC, 0.629; sensitivity 73.2%, specificity 52.5; 95% CI, 0.563–0.694; P <.001), and CONUT (AUC, 0.614; sensitivity 73.8%, specificity 50.6; 95% CI, 0.320–0.452; P <.001) demonstrated potential in predicting ESRD. Optimal cutoff values for predicting ESRD in the study analysis were PNI ≤ 42.78, GNRI ≤ 92.03, and CONUT ≥ 1.50, which investigators deemed to be key thresholds indicating a heightened risk of ESRD development.¹

Further analysis identified GNRI as an independent predictor of ESRD (hazard ratio, 0.963; 95% CI, 0.940–0.979; P <.001), along with platelet count, serum creatinine, eGFR (CKD-EPI), and triglyceride levels.¹

Investigators acknowledged multiple limitations to these findings, including inherent biases stemming from selection biases and missing data as well as the scarcity of patients with IgAN and M0 lesions in the present biopsy cohort.¹

“Our findings underscore the utility of GNRI, PNI, and COUNT score as markers reflecting crescentic proportions in patients with IgAN, with implications for ESRD risk stratification,” investigators concluded.¹ “Notably, GNRI emerges as a potentially valuable tool for identifying high-risk patients with IgAN warranting closer monitoring for ESRD progression.”

References

1. ^{Qian C, Li H, Hou Y, et al. Clinical implications of four different nutritional indexes in patients with IgA nephropathy. Front. Nutr. 11:1431910. doi: 10.3389/fnut.2024.1431910}
2. ^{Rout P, Limaiem F, Hashmi MF. IgA Nephropathy (Berger Disease). StatPearls. April 22, 2024. https://www.ncbi.nlm.nih.gov/books/NBK538214/}