highly significantp = 0.005
L-Arginine-Related Biomarkers in Relation to Chronic Airflow Obstruction (CAO) There was a highly significant difference in SDMA serum concentration between participants with and without CAO (0.518 [0.461–0.616] vs. 0.494 [0.441–0.565] μmol/L; p = 0.005), but no significant difference in ADMA concentration (0.516 [0.447–0.594] vs. 0.505 [0.447–0.557] μmol/L; p = 0.20) ( Table 3 and Figure 4 a).