0053 Effect of Changes in Intracellular Adhesion Molecule-1 on Measures of Sleepiness and 24-hour Ambulatory Blood Pressure After 4 Months of Continuous Positive Airway Pressure

Abstract

Introduction: Previous studies have shown that continuous positive airway pressure (CPAP) therapy of adults with obstructive sleep apnea (OSA) reduces circulating levels of intercellular adhesion molecule 1 (ICAM-1). ICAM-1 levels may affect daytime sleepiness and elevated blood pressure associated with OSA. Our goals were to explore associations between changes in ICAM-1 and objective and subjective measures of sleepiness, as well as 24-hour ambulatory blood pressure monitor (ABPM) parameters in adults with OSA following 4 months of CPAP treatment. Methods: We identified 140 adults with newly diagnosed OSA in the Penn Icelandic Sleep Apnea (PISA) Study, with a mean (±SD) body mass index (BMI) of 31.5±4.2 kg/m2 and apnea-hypopnea index (AHI) of 36.8±15.3 events/hour; 83.3% were males. Plasma ICAM-1 levels, 24-hour ABPM, Epworth Sleepiness Scale (ESS), and Psychomotor Vigilance Task (PVT) measures were obtained at baseline and after 4 months of CPAP treatment. Associations between changes in natural log ICAM-1 and both sleepiness and 24-hour mean arterial blood pressure (MAP) were assessed using multivariate regression models, controlling for a priori baseline covariates of age, sex, BMI, race, site, smoking status, physical activity, use of antihypertensive medications, AHI and hours/night of CPAP usage. Results: Overall, there was no significant change in ICAM-1 from baseline to follow-up among all participants after 4 months (0.027 ng/ml, p=0.52). There were no statistically significant associations between the change in ICAM-1 and change in sleepiness measures (all p>0.05) or 24-hour MAP (1.124 mm Hg, p=0.07). A nominal association between increased ICAM-1 and increased daytime MAP after 4 months was observed (1.39 mm Hg, p=0.033), although this result was not significant after correction for multiple comparisons. Conclusion: Our results do not support changes in ICAM-1 as the biological pathway linking changes in sleepiness or ABPM following CPAP treatment of adults with OSA.