0520 Relationship Between ESS and AHI in PSG vs. HSAT: Possible Modulation by Sex

Abstract Introduction Excessive daytime sleepiness is a major symptom of OSA. However, the relationship between Epworth Sleepiness Scale (ESS) and apnea-hypopnea index (AHI) is tenuous and may depend on whether the AHI is derived from an in-lab or at-home study. We analyzed ESS as a function of demographic variables and AHI in a group of patients evaluated with type 3 home sleep apnea test (HSAT) or in-the lab PSG. Methods A group of 83 HSAT patients (40 women) were matched with 83 PSG patients by race and sex. Additionally, age was matched within a decade (20-29, 30-39, etc.), and BMI was matched within ±2.5 units. ESS was regressed onto age, BMI, sex, AHI, and AHI-by-sex, AHI-by-HSAT/PSG and AHI-by-sex-by-HSAT/PSG interactions in a backward regression model. Results The mean AHI=18.0±20.0, 119 patients had AHI≥5.0, OSA severity was equally represented on HSAT and PSG studies (chi-square=0.51, p=0.92). ESS was negatively related to AHI (B=-0.58, SE=0.25, p=0.022); however, all three interaction terms were significant: AHI-by-sex (B=0.30, SE=0.14, p=0.030), AHI-by-HSAT/PSG (B=0.37, SE=0.14, p=0.009) and AHI-by-sex-by-HSAT/PSG (B=0.20, SE=0.08, p=0.013). Analyzing men and women separately, women evidenced a negative relationship between ESS and AHI (B=-0.29, SE=0.13, p=0.023) and a significant AHI-by-HSAT/PSG interaction (B=0.18, SE=0.07, p=0.009). Among men, no explanatory variables or interaction terms were significantly related to ESS. Conclusion As suggested by this limited sample, the relationship between AHI and self-reported daytime sleepiness may depend on the type of test used to evaluate the respiratory status and may also be modulated by the patient’s sex. Future studies are required to elucidate the interaction between sex, AHI and the type of apnea test in the effects of these variables on subjective daytime sleepiness. Support (if any) none