Sleep Apnea Biomarkers and Adherence to Continuous Positive Airway Pressure

Impact of Obstructive Sleep Apnea Biomarkers on Adherence to Continuous Positive Airway Pressure: Role of Pulse Wave Amplitude Drop Index, Hypoxic Burden, and Heart Rate Variability

Obstructive sleep apnea (OSA) is commonly assessed using the apnea-hypopnea index, although this measure does not fully reflect cardiovascular risk or the physiological impact of the disease. Emerging biomarkers, including sleep apnea-specific hypoxic burden, pulse wave amplitude drop index, and heart rate response, may provide additional information on cardiovascular vulnerability.

This prospective multicenter observational study will investigate the association between these biomarkers, measured from the diagnostic sleep study, and adherence to continuous positive airway pressure (CPAP) therapy after three months. Symptoms, quality of life, clinical characteristics, and changes in biomarkers under continuous positive airway pressure will also be evaluated.

This is a prospective, longitudinal, multicenter observational cohort study involving adults with newly diagnosed obstructive sleep apnea for whom continuous positive airway pressure therapy is indicated as part of routine clinical care.

At baseline, demographic and clinical characteristics, medical history, current treatments, symptom questionnaires, and results from diagnostic respiratory polygraphy or polysomnography will be collected. Hypoxic burden, pulse wave amplitude drop index, and heart rate response will be calculated from the initial sleep recording. Continuous positive airway pressure will be prescribed according to standard clinical practice.

At 12 weeks, with a permitted window of plus or minus four weeks, adherence data will be obtained from the continuous positive airway pressure device. Clinical information and questionnaires will be collected again. Participants requiring a follow-up sleep study as part of routine care may undergo respiratory polygraphy or polysomnography while receiving continuous positive airway pressure, allowing assessment of biomarker changes under treatment.

The principal analysis will examine associations between baseline biomarkers and continuous positive airway pressure adherence. Secondary analyses will assess biomarker distributions according to clinical characteristics, associations with symptoms and quality of life, and changes in biomarkers during treatment.

Inclusion Criteria:

• Newly diagnosed obstructive sleep apnea with an indication for continuous positive airway pressure therapy
• Age older than 18 years
• Written informed consent obtained

Exclusion Criteria:

• Continuous positive airway pressure treatment during the preceding 3 months
• Medical contraindication to continuous positive airway pressure therapy
• Concomitant condition likely to affect adherence to continuous positive airway pressure, including severe cognitive impairment or an unstable psychiatric disorder