Nightly Variability of Sleep‐Disordered Breathing Measured over 3 Nights

OBJECTIVE: To examine the nightly variability of sleep-disordered breathing (SDB) as measured by the apnea-hypopnea index (AHI). STUDY DESIGN AND SETTING: Retrospective comparison of 3 sequential nights of testing performed in the home in 1091 patients who were referred for diagnostic testing of SDB. RESULTS: The Pearson and Intraclass correlation coefficients ranged between 0.88 and 0.90 for each pair of nights. Based on night 1, approximately 90% of patients were classified consistently with "AHI-high" (the highest AHI measured across the 3 nights) using an AHI threshold of 5. However, 10% were misclassified on night 1 relative to the highest AHI level. CONCLUSION AND SIGNIFICANCE: These findings suggest that (1) 1 night of diagnostic testing for SDB is not sufficient to diagnosis SDB in approximately 1 of every 10 cases, and (2) there is little, if any, significant nightly change in SDB in the home environment. EBM RATING: D.