Objective: To assess the accuracy of a wrist-worn device (Watch-PAT 200) in the diagnosis of obstructive sleep apnea syndrome (OSAHS).
Methods: Forty-three adult subjects with suspected OSAHS simultaneously had a standard in-laboratory polysomnogram (PSG) and wore the Watch-PAT 200 during a full-night recording. PSG sleep and respiratory events were scored according to standard criteria. The PSG recordings were blindly manually analyzed, while Watch-PAT data were scored automatically based on the algorithm developed previously.
Results: The mean age of the subjects was (42.2 ± 12.2) years (x(-) ± s), and mean body mass index was (28.0 ± 3.9) kg/m(2). Mean PSG apnea hypopnea index (AHI) was (34.9 ± 29.9) events per hour, and mean PAT-AHI was (36.0 ± 29.2) events per hour. There was a significant correlation between PAT AHI and AHI by PSG (r = 0.931, P < 0.01). A Bland-Altman plot of PAT AHI and PSG AHI was also used to assess the accuracy of Watch-PAT 200. At lower levels of AHI, PAT tended to overestimate disease severity, while at higher levels of AHI, Watch-PAT underestimated severity. To assess sensitivity and specificity of Watch-PAT, constructed receiver operator characteristic curves using a variety of AHI threshold values (5, 15 and 30 events per hour). For AHI ≥ 5 events per hour as threshold value, the Watch-PAT diagnosing rate was 93%, and sensitivity as well as specificity were 94.7% and 80.0%. The misdiagnosis rate and missed diagnosis rate were 20.0% and 5.3%. Optimal combinations of sensitivity and specificity for the AHI threshold values (15 and 30 events per hour) were 82.6% and 100.0%, 95.0% and 95.7% respectively.
Conclusion: The Watch-PAT 200 may offer an accurate, robust, and reliable ambulatory method for the detection of OSAHS, with minimal patient discomfort.