Low homoarginine/SDMA ratio is associated with poor short- and long-term outcome after stroke in two prospective studies

Background Guanidino compounds, including asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and L-homoarginine (hArg), have been associated with cardio- and cerebrovascular events and risk. We aimed to study if low hArg/ADMA and hArg/SDMA ratios are associated with mortality and outcome after stroke. Methods In two prospective cohorts of acute stroke patients from Germany and the UK, we analyzed hArg, ADMA, and SDMA to determine hArg/ADMA and hArg/SDMA ratios. The guanidino compound levels were associated with mortality, adverse events, and neurological impairment, i.e., National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS). Results During 7.4 years, high hArg/ADMA and hArg/SDMA ratios were both associated with a reduction in all-cause mortality in patients with ischemic stroke in a UK stroke cohort (hArg/ADMA: hazard ratio (HR) 0.75 [95% confidence interval (CI) 0.62–0.92]; n = 394; P = 0.006; hArg/SDMA: HR 0.68 [0.54–0.85]; n = 394; P = 0.001). In a German stroke cohort, patients with high hArg/SDMA ratio experienced fewer adverse events compared with those with low hArg/SDMA ratios within 30 days after stroke (HR 0.73 [0.57–0.92]; n = 135; P = 0.009), whereas hArg/ADMA was not predictive. Furthermore, hArg/SDMA ratios inversely correlated with the degree of neurological impairment (NIHSS) ( r = − 0.27; P = 0.001; n = 138). Lower hArg/SDMA ratios were also found in dependent (mRS 3-6) compared with independent patients (mRS < 3; P = 0.007; n = 138), whereas hArg/ADMA did not. Conclusion These results from two prospective stroke studies reveal that hArg/SDMA ratio could prove a valuable blood-based biomarker to discriminate patients with poor short- and long-term outcome, increased neurological impairment, and severe disability after stroke.