Symmetric dimethylarginine (SDMA) outperforms asymmetric dimethylarginine (ADMA) and other methylarginines as predictor of renal and cardiovascular outcome in non-dialysis chronic kidney disease

Background Chronic kidney disease (CKD) is associated with increased risk of renal and cardiovascular events. It has been claimed that endogenous methylarginines, asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA), are contributing factors. However, earlier studies were partly contradictory and mainly focused on prevalent dialysis patients. Moreover, the potential contribution of degradation products, such as acetylated ADMA and SDMA (AcADMA and AcSDMA) and other methylarginines including L-N-G-monomethylarginine (LNMMA) remains unknown. To better understand their potential pathophysiological contribution to renal and cardiovascular events, we aimed to provide a comprehensive analysis of methylarginines in a cohort of patients with non-dialysis CKD. Methods Blood samples of 528 patients with CKD KDIGO G2 to G4 were obtained from the CARE FOR HOMe study. Baseline plasma levels of ADMA, SDMA, AcADMA, AcSDMA, and LNMMA were measured by liquid chromatography-tandem mass spectrometry. All patients were followed annually for CKD progression and for incident atherosclerotic cardiovascular events. Results During 5.1 +/- 2.1 years follow-up, 80 patients displayed CKD progression and 145 patients developed incident atherosclerotic cardiovascular events. In univariate Cox regression analyses, elevated plasma levels of all five metabolites were associated with both CKD progression and atherosclerotic cardiovascular disease. However, adjustment for confounders attenuated the prognostic implications of ADMA, LNMMA, AcADMA and AcSDMA. In contrast, patients in the highest tertile of plasma SDMA remained at highest risk for CKD progression and incident atherosclerotic cardiovascular events in fully adjusted Cox regression analyses. Conclusion Our results underline a potential pathophysiological role of SDMA in CKD progression and atherosclerotic cardiovascular disease among non-dialysis CKD patients. SDMA predicts CKD progression and future atherosclerotic cardiovascular events more consistently than other methylarginines. Future experimental and clinical studies should therefore focus upon SDMA rather than upon ADMA.