Evaluating Sleep Apnea: In-Lab Versus at-Home Recording Time and the Impact of Positional Disease

Area of Science:

• Sleep Medicine
• Respiratory Physiology

Background:

• Obstructive sleep apnea (OSA) diagnosis relies on the apnea-hypopnea index (AHI).
• Positional OSA, where sleep position influences breathing events, can complicate AHI assessment.
• Standardizing recording durations for in-lab polysomnography (PSG1) and home sleep apnea tests (HSAT) is essential for diagnostic accuracy.

Purpose of the Study:

• To establish the minimum required recording time (RRT) for both PSG1 and HSAT.
• To determine if RRT differs between patients with and without positional OSA.
• To ensure consistent reflection of the full-night AHI across different diagnostic methods and patient subgroups.

Main Methods:

• A prospective randomized crossover trial involving 54 patients with suspected OSA.
• Comparison of PSG1 and HSAT conducted within 7 days of each other.
• Analysis of both tests in 60-minute intervals to identify the RRT achieving a stable AHI difference (<5 events/h) from the end-test AHI.

Main Results:

• Overall RRT was 4 hours for PSG1 and 2 hours for HSAT.
• For non-positional OSA, RRT was 5 hours (PSG1) and 3 hours (HSAT).
• For positional OSA, RRT was 6 hours (PSG1) and 2 hours (HSAT).
• Patients with AHI < 15 events/h required shorter RRT (2 hours for both tests).
• Patients with AHI ≥ 15 events/h required 6 hours (PSG1) and 4 hours (HSAT) for stable AHI, reducing to 4 hours (PSG1) and 2 hours (HSAT) with a <10 events/h difference threshold.

Conclusions:

• Recommended RRTs to accurately reflect AHI are 6 hours for PSG1 and 3 hours for HSAT, accounting for positional OSA.
• Positional OSA significantly impacts PSG1's ability to predict end-test AHI until near completion.
• HSAT demonstrates a more rapid stabilization of AHI compared to PSG1, particularly in positional OSA cases.