Aspartate aminotransferase to alanine aminotransferase ratio and the risk of diabetic nephropathy progression in patients with type 2 diabetes mellitus: A biopsy-based study

Purpose: To study the relationship between baseline serum aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio (AAR) in both clinicopathological features and renal outcome among type 2 diabetes mellitus (T2DM) patients with biopsy-confirmed diabetic nephropathy (DN).

Methods: As a retrospective cohort study, we included 253 patients with T2DM and biopsy-confirmed DN. For receiver operating characteristic (ROC) curve showed that the optimal cut-off for AAR to predict end stage renal disease (ESRD) was 1.22. So, patients were divided into two groups according to their AAR at the time of renal biopsy: high AAR Group (those with AAR > 1.22); low AAR Group (those with AAR ≤1.22). Association between AAR and clinicopathological features as well as renal outcome were analyzed.

Results: Patients with higher AAR presented elder, more hypertensive, more insulin use, higher serum cholesterol, more proteinuria and lower estimated glomerular filtration rate (eGFR). Compared with low AAR group, patients with high AAR had more severe glomerular pathological lesions and interstitial fibrosis and tubular atrophy. For prognostic analysis, high AAR Group was associated with a higher risk of progression to ESRD in univariate analysis. No matter treated with continuous or categorical variate, higher AAR remained an independent predictor for ESRD after adjusted for various confounding factors: gender, age, the duration of diabetes, serum glucose level, hypertension, serum lipid level, smoking, insulin use, eGFR and proteinuria.

Conclusion: High AAR was associated with more severe renal pathologic lesions and worse renal function in patients with T2DM and DN, which might be a novel noninvasive predictor for ESRD.

Clinical relevance: To our knowledge, there was no biopsy-based cohort study. In our study, high AAR was associated with more severe renal pathologic lesions and worse renal function in patients with T2DM and DN, which might be a novel noninvasive predictor of ESRD for patients with DN.