To determine factors that are associated with OSA therapy outcomes with auto-titrating positive airway pressure (APAP).

We sequentially grouped patients from a retrospective cohort based on APAP efficacy (sufficiently vs. insufficiently treated; insufficiently treatment defined as residual AHI of ≥ 5), therapy adherence (adherent vs. non-adherent, non-adherence defined as < 70% usage for ≥ 4 h/night), and therapy outcomes (optimal vs. non-optimal and non-optimal outcomes defined as non-adherent and/or insufficiently treated). We subsequently compared each group.

The insufficiently treated were older (68.4 ± 12.5 vs. 60.4 ± 13.1 years, p < 0.01) and had lower BMI (31.9 ± 6.3 vs. 37.9 ± 9.1 kg/m², p < 0.01). They had higher baseline central apnea indices (CAI), longer leaks, higher peak pressures, and were less compliant. The non-adherent were younger (61.1 ± 12.6 vs. 65.5 ± 13.2 years, p = 0.03) and comprised more females (56.1 vs. 43.9%, p = 0.04). The leak duration per usage hour was higher in the non-compliant (median: 1.5; IQR 7.9 vs. median: 0.3; IQR 1.9 min/h; p < 0.01). The non-optimally treated had lower BMI, longer leaks, and less nightly usage. Multivariate analyses showed that leak duration was the common factor associated with treatment effectiveness and optimal therapy outcomes.

Various demographic and clinical factors were associated with treatment efficacy and adherence. However, leak duration was the common factor related to treatment efficacy and overall optimal therapy outcomes.