0618 Can Ventilatory Burden or Hypoxic Burden Predict Improvement in Short-Term Sleepiness in Response to CPAP Treatment in OSA Patients?

Abstract Introduction Hypoxic burden (HB) and ventilatory burden (VB) were developed as alternatives to AHI in predicting OSA outcomes. The abilities of HB and VB to predict long-term outcomes have been explored extensively, yet each’s ability to predict short-term outcomes is unknown. Methods This is a secondary analysis of the APPLES study that investigated the neurocognitive effects of CPAP therapy on OSA patients. This analysis explored how HB and VB were associated with short-term sleepiness measures. Sleepiness was measured subjectively with the Epworth Sleepiness Scale (ESS), and objectively with lapses on psychomotor vigilance test (PVT). Using the SpO2 signal, HB was calculated as the area under the desaturation curve during all desaturation events (sustained >3% dip in SpO2). VB represents the proportion of overnight breaths with less than 50% normalized amplitude. Results There was a statistically significant decline in both ESS (x ̅=-2.82,p= <.001) and PVT (x ̅=-0.20,p= .005) in the treated group; the clinical significance of the difference is unknown. Correcting for age, gender, and BMI, HB significantly predicted a decline in ESS (p<.001, R^2adj.=.285). After adjusting for baseline ESS, HB was a significant, but weaker, predictor of ESS (p=.044, R^2adj.=.045). HB significantly predicted a decrease in PVT (p=.002, R^2adj.=.0429). A much weaker association between HB and PVT was found after adjusting for baseline PVT (p=.099, R^2adj.=.374). AHI significantly predicted changes in PVT and ESS, but this association disappeared after correcting for baseline measurements. VB wasn’t associated with PVT or ESS. Conclusion HB weakly predicted both subjective (ESS) and objective (PVT) measures of sleepiness after correcting for covariates and baseline measures. VB was not associated with any changes in sleepiness. Most models had an adjusted R^2< 5%, indicating that the models were good fits for the data even if the covariates were not significant. Since the clinical significance of the changes in sleepiness is unknown for this study, and the original study didn’t find improvements in cognition post-treatment, it is not surprising that VB and HB were poor correlates of change in sleepiness in this dataset. Further studies may want to examine these associations with clinically meaningful changes in sleepiness. Support (if any) R01HL171813, K25HL151912