Smartwatch-based detection of moderate-to-severe and high-risk obstructive sleep apnea.

PURPOSE: Obstructive sleep apnea (OSA) is a prevalent condition associated with long-term consequences, such as cardiovascular and neurocognitive diseases, yet many cases remain undiagnosed and therefore untreated due to the cost and limited access to traditional in-lab overnight polysomnography (PSG). The ubiquity of consumer wearable technology offers a practical way to mitigate these limitations, enabling more accessible, large-scale screening. However, the clinical validity of these devices requires further testing.

METHODS

In this novel prospective study, we rigorously evaluated the diagnostic performance of the Samsung Galaxy Watch for detecting moderate-to-severe OSA (apnea-hypopnea index, AHI ≥ 15 events/h) compared to in-lab PSG using the AHI, and "high-risk" OSA subjects using the PSG-derived hypoxic burden (HB) criteria. We enrolled 152 adults aged 22 years or older with a prior diagnosis of moderate-to-severe OSA or a high pre-test likelihood of having it (STOP-Bang score ≥ 3), who wore the smartwatch during two in-lab PSG nights (147 completed both nights; total 1,850 h of in-lab PSG sleep): an initial in-lab PSG night, followed by ≥ 3 watch-only at-home nights, and then a second in-lab PSG night. In addition to AHI, we evaluated Galaxy Watch performance across PSG-derived HB-defined risk strata (low- vs. high-risk OSA) as HB integrates the depth, duration, and frequency of oxygen desaturations and has been shown to better reflect cardiometabolic risk and disease severity than AHI.

RESULTS

In our cohort, the Galaxy Watch achieved an area under the receiver operating characteristic (AUROC) curve of 0.94 (95% CI 0.889-0.980) for detecting moderate-to-severe OSA. With the default estimated AHI (eAHI) threshold of 15, the device yielded a sensitivity of 94.1% (95% CI 84.1-98%) and a specificity of 66.7% (95% CI 51-79.4%), while with the cohort-optimized eAHI threshold of 25.95, sensitivity was 82.4% (95% CI 69.7-90.4%) and specificity was 94.9% (95% CI 83.1-98.6%). Notably, within the HB defined high-risk OSA group, the Galaxy Watch achieved 100% sensitivity and 100% specificity using the default threshold, indicating robust discrimination between HB-defined low- and high-risk OSA categories.

CONCLUSION

Overall, these findings highlight the substantial potential of consumer-grade wearables to accurately detect moderate-to-severe sleep apnea using both AHI- and HB-defined risk strata across controlled and real-world settings.

REGISTRATION: ClinicalTrials.gov ID: NCT06603441; First posted: 2024-09-19.

CURRENT KNOWLEDGE/STUDY RATIONALE: Obstructive sleep apnea (OSA) remains substantially underdiagnosed because definitive testing with polysomnography (PSG) is resource-intensive and not readily accessible to all patients. Although consumer smartwatches offer a promising approach for large-scale OSA screening, prospective validation against PSG and evaluation using physiologically meaningful measures such as hypoxic burden have been limited.

STUDY IMPACT: In this prospective study of 152 adults undergoing repeated PSG and smartwatch assessment, the Galaxy Watch demonstrated high accuracy for detecting moderate-to-severe OSA and showed excellent performance for identifying individuals with high hypoxic burden, a subgroup at elevated cardiometabolic risk. These findings support the use of consumer-grade wearable technology as a scalable, accessible screening tool to improve OSA risk identification, triage, and referral for definitive diagnostic evaluation.