The clinical value of metabolic indicators in immunoglobulin A nephropathy

Immunoglobulin A nephropathy (IgAN) is a leading cause of end-stage renal disease (ESRD). There is a critical need for sensitive biomarkers to predict disease progression, as traditional indicators like serum creatinine (Scr) have limitations. This study investigates the association of routine metabolic indicators with renal function, pathology, and hospitalization expenses in IgAN patients. In this cross-sectional study, lactate dehydrogenase (LDH) levels were significantly correlated with mesangial hypercellularity (M) and tubular atrophy/interstitial fibrosis (T) in the MEST-C score in the Oxford classification. Furthermore, LDH levels showed a consistent association with estimated glomerular filtration rate (eGFR) and total hospitalization expenses in unadjusted and multivariable-adjusted analyses. Serum uric acid (SUA) levels also demonstrated a strong relationship with renal function. In lipid metabolism, high-density lipoprotein cholesterol was significantly associated with eGFR after multivariable adjustment, whereas triglycerides (TGs) showed correlations with eGFR only in the unadjusted analysis. Serum total protein (TP) levels exhibited a linear positive correlation with eGFR in the unadjusted analysis and emerged as a robust predictor of M, segmental glomerulosclerosis (S), and T lesions in the Oxford Classification. After false discovery rate correction for multiple comparisons, TP was found to be significantly associated with T lesions, which was the most crucial finding of our study, whereas associations involving LDH and other markers were exploratory. Importantly, S and T lesions were strongly associated with a decline in renal function and M1 lesions were found to respond favorably to corticosteroid therapy, whereas T2 lesions signaled an increased risk of progression to ESRD. These hypothesis-generating findings suggest that the strict control of lipid and SUA levels is essential for patients with IgAN in clinical practice. Elevated LDH and decreased TP levels may alert clinicians to the risks of renal function deterioration and ESRD. Moreover, such patients may respond favorably to corticosteroid therapy, which should be considered within the framework of KDIGO 2025 guidelines based on comprehensive risk assessment.