Comprehensive Positive Airway Pressure Titration Parameters as Predictors of Therapeutic Adherence in Obstructive Sleep Apnea

Background: Whether the physiological response during positive airway pressure (PAP) titration predicts adherence independently of baseline severity is unclear. Methods: In 304 patients who underwent manual PAP titration at a tertiary university hospital between 2020 and 2022, adherence was defined by Korean reimbursement criteria (≥4 h/night on ≥70% of nights within any consecutive 30-day period during the initial 90 days). Titration parameters were compared using tests appropriate to each distribution and entered into logistic regression adjusted for age, sex, body mass index and baseline apnea–hypopnea index (AHI), with bootstrap validation. Results: Adherent (n = 238) and non-adherent (n = 66) groups had comparable baseline severity. Three titration parameters differed: AHI reduction rate (p = 0.033), lowest oxygen saturation (SpO2; p = 0.010) and rapid eye movement-sleep proportion (p = 0.021). Adding these parameters to a confounder-only model raised the area under the curve from 0.566 to 0.683 (p < 0.001; optimism-corrected, 0.632). Adjusted for confounders alone, all three were significant, but with mutual adjustment only the lowest SpO2 remained independent (odds ratio, 1.117 per 1%; 95% CI, 1.028–1.214). Conclusions: Among the physiological parameters recorded during PAP titration, the lowest SpO2 was the most robust predictor of short-term adherence, independent of both baseline disease severity and baseline hypoxemia. Prospective validation is required.