Sleep apnea (SA) is traditionally diagnosed with a single night sleep study, however research suggest that most patients have variability in SA severity, placing them at risk for misdiagnosis. The purpose of this study was to examine the variability of SA severity in a diverse population that underwent repeated, longitudinal testing.
This study evaluated 149 adults across the United States, who used Wesper Lab, a home sleep test capable of repeat, longitudinal testing. A total of 1,184 tests were examined, with a mean of 7.9 (SD 6.9) tests per subject. Subjects that reported using any SA therapy during testing, or completed <2, tests were removed from analysis. Apnea/Hypopnea Index (AHI) was assessed to determine the presence and severity of SA. A subgroup of subjects with a previous diagnosis of SA, that reported their diagnosed SA severity, were evaluated for diagnostic accuracy.
Of the 149 subjects, 69.7% had AHI scores that varied in severity. 51% had scores within the normal (AHI <5) and abnormal (AHI >5) range. 21% had tests that included both normal and mild scores, 18.1% had both normal and moderate scores, and 6% had both normal and severe scores. The average AHI point increase across all tests was 12.4 (SEM 0.99). Reported SA severity in previously diagnosed subjects (N=65) was compared to the new test scores. 58.4% had at least one test that did not agree with their initial diagnosis. 26.1% had scores with a worse severity than their initial diagnosis. Of the subjects that reported having mild SA (N = 27), 11% had scores that placed them within the severe range. Of the subjects that reported having moderate SA (N=22), 338% had scores within the severe range.
Repeat testing in a diverse population confirmed high night-to-night variability of AHI in the majority of SA sufferers. Patients with mild to moderate SA were at high risk for being classified as normal, or diagnosed with the incorrect severity, which may unknowingly increase health risk and reduce the effectiveness of some therapies. Standardizing multi-night testing for sleep apnea will improve diagnostic accuracy and health outcomes.