The role of the lactate dehydrogenase-to-albumin ratio in predicting renal prognosis in Chinese IgA nephropathy patients: a retrospective cohort study

Background Immunoglobulin A nephropathy (IgAN) is one of the most common types of primary glomerulonephritis and is an important cause of end-stage renal disease (ESRD) worldwide. Inflammation has been shown to be associated with its basic pathogenesis. The lactate dehydrogenase-to-albumin ratio (LAR), a novel marker of inflammation and nutritional status, has been studied in various diseases. However, whether the LAR also plays a critical role in Chinese patients with IgAN remains unknown. Thus, we conducted this retrospective study to evaluate the role of the LAR in predicting clinicopathologic changes and disease prognosis in IgAN patients. Methods A total of 1,276 patients with biopsy-proven IgAN were enrolled in this study. The patients were grouped into a high LAR group (LAR ≥4.05, n = 738) and a low LAR group (LAR <4.05, n = 538) based on the cutoff value of the LAR with regard to the Youden index. The study endpoint was a composite endpoint that referred to ESRD and/or an estimated glomerular filtration rate (eGFR) that decreased by more than 50% compared with baseline. The predictive value was determined by the area under the receiver operating characteristic curve (AUROC). Kaplan–Meier and Cox proportional hazards analyses were performed to evaluate the value of the LAR in predicting renal progression and patient prognosis. Results IgAN patients with a high LAR had an increased incidence of anemia and increased levels of proteinuria, serum creatinine, and serum lipids. Multivariate Cox regression analysis indicated that a high LAR was an independent risk factor for IgAN even after adjustment for important clinicopathological parameters (HR = 1.844, 95% CI = 1.138–2.988, p = 0.013). Kaplan–Meier analysis revealed that a high LAR was significantly associated with a poor renal prognosis in patients with IgAN ( p < 0.001). According to subgroup analysis stratified by sex, renal function, treatment, anemia status, or proteinuria level, a high LAR was consistently related to a worse renal outcome. Conclusion An elevated LAR affects renal progression and prognosis in patients with IgAN and could be a novel marker for the management of IgAN patients in the future.