Residual AHI Measurement from PAP Devices Versus Home Polygraphy: A Method Comparison Study Using Real World Data

Area of Science:

• Sleep Medicine
• Respiratory Medicine
• Medical Device Technology

Background:

• Positive airway pressure (PAP) therapy is a standard treatment for obstructive sleep apnoea (OSA).
• Device-derived residual apnoea hypopnoea index (AHI) from PAP downloads is commonly used to monitor treatment effectiveness.
• The real-world accuracy of PAP device-reported AHI compared to objective measurements remains under investigation.

Purpose of the Study:

• To evaluate the agreement between PAP device-derived AHI and AHI measured by home cardiorespiratory polygraphy (CRP).
• To assess the diagnostic accuracy of PAP device data for detecting inadequate OSA treatment.
• To examine the impact of interface leak on AHI underestimation by PAP devices.

Main Methods:

• Secondary analysis of the 3DPiPPIn randomised controlled trial involving adults with OSA (AHI ≥15 events/hr) naive to PAP therapy.
• Two-night home CRP was performed at three and six months post-initiation of PAP therapy.
• Residual AHI was obtained from Löwenstein PAP devices; agreement assessed using Bland-Altman analysis, ICC, and weighted Kappa.

Main Results:

• PAP device-derived AHI consistently underestimated CRP-derived AHI, with poor agreement (ICCs: 0.02 at 3 months, 0.16 at 6 months).
• Diagnostic agreement for inadequate control (AHI ≥7 events/hr) was low (Kappa < 0.10 at both time points).
• Higher interface leak was significantly associated with greater AHI underestimation by PAP devices (p < 0.0001).

Conclusions:

• PAP device downloads substantially underestimate residual AHI and show poor agreement with home CRP.
• Device-derived AHI has significant limitations in real-world OSA management, especially with interface leak.
• Confirmatory assessment with cardiorespiratory polygraphy is essential when treatment adequacy is uncertain.