Table 2.
Variable | Model 1 (Unadjusted) |
Model 2 (Model 1 + Age, Sex, and BMI) |
Model 3 (Model 2 + Sleep Factors)* |
Model 4 (Model 3 + Comorbidities)† |
||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
β (SE) | β SD | P Value | β (SE) | β SD | P Value | β (SE) | β SD | P Value | β (SE) | β SD | P Value | |
Time, mo | −0.012 (0.005) | −0.037 | 0.019 | −0.012 (0.005) | −0.037 | 0.019 | −0.012 (0.005) | −0.037 | 0.019 | −0.014 (0.005) | −0.043 | 0.007 |
ArTH, %Ve | 0.026 (0.010) | 0.299 | 0.008 | 0.026 (0.010) | 0.300 | 0.007 | 0.025 (0.010) | 0.291 | 0.010 | 0.023 (0.010) | 0.263 | 0.021 |
Loop gain | −0.496 (1.098) | −0.033 | 0.652 | −0.521 (1.141) | −0.035 | 0.649 | −0.078 (1.197) | −0.005 | 0.948 | −0.212 (1.191) | −0.014 | 0.859 |
Vpassive, %Ve | 0.019 (0.011) | 0.167 | 0.079 | 0.021 (0.011) | 0.184 | 0.056 | 0.019 (0.012) | 0.167 | 0.109 | 0.020 (0.012) | 0.169 | 0.105 |
Vcomp, %Ve | −0.007 (0.009) | −0.059 | 0.430 | −0.007 (0.009) | −0.060 | 0.425 | −0.008 (0.019) | −0.063 | 0.399 | −0.009 (0.009) | −0.076 | 0.312 |
Vcomp2 | −4.75 × 10−4 (1.67 × 10−4) | −0.223 | 0.005 | −4.71 × 10−4 (1.70 × 10−4) | −0.221 | 0.006 | −4.58 × 10−4 (1.69 × 10−4) | −0.215 | 0.007 | −4.49 × 10−4 (1.68 × 10−4) | −0.214 | 0.008 |
Definition of abbreviations: AHI = apnea–hypopnea index; ArTH = arousal threshold; BMI = body mass index; CAD = coronary artery disease; CPAP = continuous positive airway pressure; ESS = Epworth Sleepiness Scale; Vcomp = pharyngeal muscle compensation (higher value represents higher compensation); Ve = eupneic ventilation; Vpassive = 1/pharyngeal collapsibility (higher value represents lower collapsibility). The model contains four main trait effects and interaction terms with a P value of <0.20 in exploratory analyses. Trait values were subtracted from the mean before terms were generated and applied to the model (see Measurement of Physiological Traits in the online supplement). “β SD” describes the number of SDs of change in CPAP adherence per each SD increase in each term. This enables the comparison of effect sizes among physiological traits. The mean values of the physiological traits before mean subtraction are as follows: Vpassive = 80.9 ± 26.2%, Vpassive transformed = 63.0 ± 23.4%, loop gain = 0.67 ± 0.18, Vcomp = 0.43 ± 23.8%, ArTH = 128.5 ± 37.5%, and ArTH transformed = 143.5 ± 31.6%. Bold indicates P < 0.05.
Sleep factors: ESS score and AHI.
Comorbidities: anxiety, depression, history of atrial fibrillation, and history of acute myocardial infarction (present vs. absent).