0619 Hypoxic Burden in Negative Home Sleep Studies: Risk Stratification and Prediction of Later OSA Detection

Introduction There is promise in analyzing Hypoxic Burden (HB) to potentially identify high-risk patients even when AHI is below the diagnostic threshold. After analyzing 4,197 patients with multi-night HSAT testing using both 3% and 4% desaturation criteria, patients with night-1 negative results (sAHI < 5) were isolated. Subset analysis was performed on available HB data. Prevalence of high-risk HB (>20% minute/hour) was identified in initially negative patients. Using both desaturation criteria, we assessed HB’s predictive value to later detect OSA (AHI ≥5 on subsequent nights). Methods After analyzing 4,197 patients with multi-night HSAT testing using both 3% and 4% desaturation criteria, patients with night-1 negative results (sAHI < 5) were isolated. Subset analysis was performed on available HB data. Prevalence of high-risk HB (>20% minute/hour) was identified in initially negative patients. Using both desaturation criteria, we assessed HB’s predictive value to later detect OSA (AHI ≥5 on subsequent nights). Results Using the 3% criterion, 109 patients had a night-1 negative study (sAHI < 5), and none exhibited high-risk hypoxic burden (HB >20%). Despite this, 56 patients (51.4%) were later diagnosed with OSA (AHI ≥5) on subsequent nights. In contrast, with the 4% criterion, 332 patients tested negative on night 1, of whom 48 (14.5%) showed high-risk HB despite normal AHI, and 99 (29.8%) later demonstrated OSA. The 4% threshold identified a subgroup with elevated HB despite negative AHI. Overall, HB’s predictive value varied by desaturation criterion, with higher subsequent OSA detection in the 4% negative group. Conclusion Using 4% desaturation criteria, hypoxic burden can identify high-risk patients even when conventional AHI is negative. Among initially negative patients, approximately 15% had HB >20%, indicating significant nocturnal hypoxemia despite AHI < 5. Furthermore, 29.8% of these patients were later diagnosed with OSA, suggesting that HB may help flag individuals who would benefit from repeat testing. Incorporating multi-night HSAT with HB assessment could improve risk stratification and reduce false negatives. These findings support HB as a complementary metric for detecting patients at risk for sleep-disordered breathing and its associated cardiovascular consequences. Support (if any)