Background: Home sleep apnea testing (HSAT) underestimates obstructive sleep apnea (OSA) severity. Overnight oxygen desaturation has been shown to be a strong predictor of incident stroke, and may be helpful in determining which patients with lower apnea-hypopnea indices (AHIs) should be offered treatment.
Objectives: To examine whether a modified definition for OSA that uses oxygen desaturation (i.e., AHI 5-14.9 per hour and lowest O2 desaturation ≤88%), as compared to an AHI ≥ 15 per hour, would impact: (1) changes in Epworth Sleepiness Scale scores post-continuous positive airway pressure (CPAP) initiation; (2) CPAP compliance rates; and (3) the accuracy of automated versus manual scoring of HSAT.
Methods: One hundred and six patients with a prior stroke or transient ischemic attack (TIA) underwent HSAT. Epworth Sleepiness Scale and CPAP compliance were measured at baseline and 3-6 months.
Results: Median age was 67.5 years, 57.5% male, and 76.4% presented with stroke. Fifty-nine patients were diagnosed with OSA; of these 54.2% met criteria for the "modified definition" for OSA (AHI 5-14.9 per hour with oxygen desaturation) and 45.8% met criteria for the "classic definition" for OSA (AHI ≥15). The modified (versus classic) definition had: (1) a greater decrease in ESS (P = .05) post-CPAP initiation; (2) comparable CPAP compliance rates; and (3) comparable automatically versus manually scored AHIs (Spearman's rho = .96, Cohen's Kappa ≥ .75 for both definitions, P < .001).
Conclusions: Using a modified definition of OSA that uses a lower AHI cutoff and includes an oxygen desaturation cutoff in the setting of HSAT for stroke or transient ischemic attack (TIA) patients may improve daytime sleepiness post-CPAP initiation, while not significantly affecting CPAP compliance rates nor the accuracy of automated scoring.
Keywords: Home sleep apnea testing; definitions; obstructive sleep apnea; stroke; transient ischemic attack.
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