Study objectives: This study investigated the minimum recording time needed during out-of-center sleep testing (OCST) to accurately diagnose the presence and severity of obstructive sleep apnea (OSA).
Design and setting: A retrospective analysis was conducted of OCSTs performed from October 2009 to May 2012 at the Mayo Clinic Center of Sleep Medicine using the portable Embletta™ system.
Patients or participants: Demographic information was collected for patients who underwent OCSTs during the study period, including presenting symptoms, examination findings, and comorbidities.
Intervention: Each study was divided into 60-, 120-, 180-, 240-, 300-, 360-, and 420-min intervals beginning at the recording start time to determine the respiratory event index (REI) for each of these time intervals. These interval values were then compared to the original REI derived from the total recording time (REITRT) by a paired t-test and concordance correlation coefficient (CCC).
Measurements and results: There were significant differences between the REITRT and the REI from the 60-min (P < 0.0001), 120-min (0.0001), 180-min (0.003) and 240-min (0.006) intervals with a lack of concordance, suggesting these intervals are poor diagnostic correlates for the REITRT. REIs determined at 300, 360, and 420 min were not significantly different from the REITRT and had highly significant CCCs, 0.963, 0.987, and 0.995, respectively.
Conclusions: The results suggest that at least 300 min recording time during out-of-center sleep testing is needed for accurate diagnosis of obstructive sleep apnea and determination of obstructive sleep apnea severity.
Keywords: home sleep test; obstructive sleep apnea; out-of-center sleep test.