Modeling the effects of obstructive sleep apnea and hypertension in Vietnam veterans with PTSD

Abstract

Purpose: The present work aimed to extend models suggesting that obstructive sleep apnea (OSA) is associated with worse cognitive performance in community-dwelling older adults. We hypothesized that in addition to indices of OSA severity, hypertension is associated with worse cognitive performance in such adults. Methods: The PTSD Apnea Clinical Study recruited 120 community-dwelling, male veterans diagnosed with PTSD, ages 55 and older. The Rey Auditory Verbal Learning Test (RAVLT) and Color-Word Interference Test (CWIT) were measures of auditory verbal memory and executive function, respectively. Apnea-hypopnea index (AHI), minimum and mean pulse oximeter oxygen saturation (min SpO2, mean SpO2) indicators were determined during standard overnight polysomnography. Multivariate linear regression and receiver operating characteristic (ROC) curve analyses were performed. Results: In regression models, AHI (β = -4.099; p < 0.01) and hypertension (β = -4.500; p < 0.05) predicted RAVLT; hypertension alone (β = 9.146; p < 0.01) predicted CWIT. ROC analyses selected min SpO2 cut-points of 85% for RAVLT (κ = 0.27; χ = 8.23, p < 0.01) and 80% for CWIT (κ = 0.25; χ = 12.65, p < 0.01). Min SpO2 cut-points and hypertension were significant when added simultaneously in a regression model for RAVLT (min SpO2, β = 4.452; p < 0.05; hypertension, β = -4.332; p < 0.05), and in separate models for CWIT (min SpO2, β = -8.286; p < 0.05; hypertension, β = -8.993; p < 0.01). Conclusions: OSA severity and presence of self-reported hypertension are associated with poor auditory verbal memory and executive function in older adults. © 2011 Springer-Verlag.