A79-06 Intermittent Hypoxia in Patients Undergoing Home Sleep Testing for OSA With Correlation to Their Lung Function

Abstract Introduction Obstructive sleep apnea (OSA) is characterized by recurrent episodes of partial or complete upper airway collapse during sleep, resulting in chronic intermittent hypoxia (IH). Apnea-Hypopnea Index (AHI) reflects only the frequency of obstructive events per hour of sleep, without accounting for their duration or the degree of oxygen desaturation, providing an incomplete picture of disease severity. Oxygen desaturation index or percentage of total sleep time spent with saturation below 88% are stronger predictors of morbidity and mortality than AHI alone. Abnormal pulmonary function tests markedly increase susceptibility to nocturnal oxygen desaturation and intermittent hypoxia during sleep studies. This study aimed to evaluate the extent of intermittent hypoxia in patients undergoing home sleep testing (HST) for suspected OSA and its correlation with pulmonary function. Methods We conducted a retrospective study of adults who underwent ≥4 hours of HST between January 2023 and June 2025, with concurrent pulmonary function testing (PFT) within six months before or after the sleep study. IH was defined as a reduction in saturation of 88% for ≥60 seconds. Inclusion criteria comprised baseline SpO2≥90% and average SpO2 ≥88%. Patients with shorter recording times, baseline hypoxemia, or missing PFTs were excluded. Logistic regression models were employed to assess associations between PFT indices and IH outcomes, adjusting for age, sex, body mass index (BMI), and smoking history. Results A total of 243 patients met the inclusion criteria, of whom 66% (n = 162)demonstrated significant IH. There was a significant association between the duration of hypoxia and the severity of forced vital capacity (FVC) (odds ratioOR 1.02, 95% CI: 1.01-1.04, p=0.01) and diffusing capacity for carbon monoxide (DLCO) (OR 1.02, 95% CI: 1.01-1.03, p=0.04) . FEV1 and FEV1/FVC ratio did not reach statistical significance. Patients with obstructive (OR 2.3, 95% CI:1.26-4.2,p=0.001) or restrictive lung disease (OR 2.1, 95% CI:1.3-3.3, p = 0.02)demonstrated prolonged duration of intermittent hypoxia compared to those with normal pulmonary function. Across the dataset, AHI ≥5 consistently correlated with an increased risk of intermittent hypoxia. Conclusion In this cohort of patients undergoing sleep testing for suspected OSA, impaired pulmonary function emerged as an independent determinant of intermittent hypoxia severity. These results emphasize the need to include comprehensive pulmonary function testing when assessing patients with OSA, as this may help detect individuals at heightened risk for significant nocturnal desaturation and related cardiopulmonary morbidity. This abstract is funded by: None