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

ABSTRACT Objectives To determine the minimum required recording time (RRT) for in‐lab Type 1 polysomnography (PSG1) and home sleep apnea test with Type 3 portable monitoring (HSAT) that consistently reflects the full‐night apnea‐hypopnea index (AHI) in patients with and without positional obstructive sleep apnea (OSA). Methods This prospective randomized crossover trial with 54 consecutive patients with suspected OSA involved PSG1 and HSAT no more than 7 days apart (108 exams). Each test was analyzed in 60‐min intervals. Minimum RRT was the point the test achieved and maintained an AHI difference < 5 events/h from end‐test AHI. Patients were grouped into non‐positional and positional OSA, and by severity subgroups. Results Minimum RRT in PSG1/HSAT was 4 h/2 h for the entire cohort, 5 h/3 h for non‐positional OSA and 6 h/2 h for positional OSA, respectively. Patients with AHI < 15 events/h showed minimum RRT of 2 h in both exams and a clinically irrelevant AHI difference (below 5 events/h) between PSG1 and HSAT after 4 h. Conversely, patients with AHI ≥ 15 events/h presented minimum RRT of 6 h/4 h in PSG1/HSAT, respectively. By adopting an AHI difference threshold of < 10 events/h, minimum RRT in this latter group was 4 h/2 h in PSG1/HSAT. Conclusion To account for the influence of positional and non‐positional OSA, the minimum required recording times for PSG1 and HSAT that safely reflect the end‐test AHI are 6 and 3 h, respectively. Unlike HSAT, positional OSA hinders PSG1's ability to adequately anticipate end‐test AHI until the exam is nearly complete. Level of Evidence 2.