Relationship between serum asymmetric dimethylarginine level and obstructive sleep apnea syndrome severity

Aim: The repetitive hypoxemia can induce oxidative stress mechanisms. Oxidative stress increases serum asymmetric dimethylarginine (ADMA) levels in patients with obstructive sleep apnea syndrome (OSAS). To in- vestigate the relationship between serumlevels of ADMA and OSAS severity. Methods: 330 patient’s records, who underwent overnight polysomnogra- phy (PSG) were retrospectively examined. The patients who had an abnor- mal serum glucose, lipid, thyroid, renal and liver function tests levels, had excluded. 72 patients had participating criteria. Patients were categorized into five groups according to apnea/hipopnea index (AHI). Measurement of ADMA levels were performed by ELISA kit. Results: The mean age was 44,19 ± 14,24 years. 31,9 % of the patients were female. Patients in normal group, severe, medium, mild and posi- tional–REM dependent OSAS group were 26,4%, 25%, 6,9 %, 16,7% and 25%; respectively. A significant positive correlation was found between AHI and ADMA (r= 0,483; p<0,001). Appropriate cut-off criterion was set at 1,39 for ADMA. Sensitivity for this value was 73,58 % (95 % Confidence Interval (CI): 61,71- % 85,45 %) and specificity was 94,74 % (95 % CI: 84,70- % to 100%). Accuracy or correct classification rate was found to be 79,17 %. The positive predictive value was 97,5 % and negative predictive value was 56,25 %. The positive likelihood ratio (LR +) was 13,98 (LR + > 10) and the negative likelihood ratio was (LR-) 0,28 (R- <1). Conclusions: ADMA was found to be a strong and good diagnostic tool among patients with normal levels for glucose, lipid, TSH, creatinine and liver function tests.