Examining the association between CT-defined low tongue posture and CPAP adherence

Area of Science:

• Medical Imaging
• Sleep Medicine
• Respiratory Medicine

Background:

• Continuous Positive Airway Pressure (CPAP) therapy is a primary treatment for Obstructive Sleep Apnea (OSA).
• Patient adherence to CPAP therapy remains a significant clinical challenge, impacting treatment efficacy.
• Low tongue posture (LTP) is a potential anatomical factor influencing OSA severity and treatment response.

Purpose of the Study:

• To investigate the association between CT-defined low tongue posture (LTP) and adherence to CPAP therapy in adults with OSA.
• To determine if a visible tongue-palate air gap on sagittal CT scans predicts CPAP adherence.
• To evaluate LTP as a potential biomarker for predicting CPAP treatment outcomes.

Main Methods:

• Retrospective analysis of 430 adult OSA patients (AHI ≥ 20) with polysomnography (PSG), CT imaging, and CPAP initiation.
• CT-defined LTP was identified by assessing the tongue-palate air gap on mid-sagittal CT images.
• CPAP adherence at 3 months was objectively measured using device-recorded data, with good adherence defined as ≥ 70% and ≥ 50% of nights with ≥ 4 hours of use.

Main Results:

• CT-defined low tongue posture (LTP) was present in 26.7% of the study cohort (115 patients).
• Patients with LTP exhibited significantly lower average CPAP adherence (39.6%) compared to those without LTP (54.1%, p < 0.001).
• Multivariate analysis revealed that LTP was independently associated with lower odds of achieving good CPAP adherence at both 70% (aOR 0.447) and 50% (aOR 0.496) thresholds.

Conclusions:

• CT-defined low tongue posture is significantly associated with poorer CPAP adherence in patients with obstructive sleep apnea.
• The current CT definition of LTP lacks standardization and demonstrates limited specificity, particularly at higher adherence thresholds (70%).
• LTP should be considered an adjunctive risk marker for predicting CPAP adherence challenges, rather than a standalone diagnostic or screening tool.