Comparative Analysis of Apnea-Hypopnea Duration and Oxidative Stress Markers for Diagnosis and Classification of Obstructive Sleep Apnea

Background/Objectives: Obstructive sleep apnea (OSA) diagnosis relies primarily on the apnea-hypopnea index (AHI), which measures event frequency but not duration. This study aimed to evaluate the diagnostic and classificatory potential of apnea and hypopnea duration (AHD) and oxidative stress markers in OSA. Methods: This case-control study included 47 patients with newly diagnosed OSA and 12 healthy controls. Participants underwent polysomnography and oxidative stress assessment through measurement of total-thiol, native-thiol, disulfide, myeloperoxidase, paraoxonase, catalase, malate dehydrogenase, total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI). The patient group was classified and compared based on OSA severity. Results: Total AHD of the severe OSA group was significantly longer than both other groups (p < 0.001). TAS levels of both OSA groups were significantly lower compared to controls (p = 0.006). TAS demonstrated moderate correlations with polysomnography parameters. A total AHD value of >12 min discriminated OSA with 100% sensitivity and specificity. A total AHD value of >80 min distinguished severe OSA with 100% sensitivity and 97.22% specificity. Conclusions: Total AHD is a valuable parameter for OSA diagnosis and severity classification, demonstrating superior discriminatory performance compared to the widely-used AHI. Although TAS was associated with OSA presence, oxidative stress parameters have limited utility for assessing OSA severity.