Currently submitted to: Journal of Medical Internet Research
Date Submitted: Jan 20, 2026
Open Peer Review Period: Jan 21, 2026 - Mar 18, 2026
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Photoplethysmography in Healthcare: An Umbrella Review of Clinical Applications, Validation, and Evidence Gaps
ABSTRACT
Background:
Photoplethysmography (PPG) is widely used in consumer and clinical devices for heart rate, rhythm, sleep, respiratory, and hemodynamic monitoring. However, rapid expansion of applications has produced a fragmented evidence base with heterogeneous methods and variable validation quality.
Objective:
To synthesize and critically appraise systematic reviews evaluating PPG-based applications in healthcare, map major clinical domains and methodological practices, and identify limitations and priorities for future research.
Methods:
A protocolized umbrella review (PROSPERO CRD420251015845) was conducted across six databases. Systematic reviews and meta-analyses involving human PPG applications were included. Screening, extraction, and AMSTAR-2 quality assessment were performed in duplicate following PRISMA-S and PRIOR guidelines.
Results:
Fifty-nine systematic reviews were included. PPG showed consistent accuracy for resting heart-rate monitoring and strong performance for opportunistic atrial fibrillation screening when paired with confirmatory ECG. HRV estimation, stress monitoring, sleep assessment, neonatal and maternal monitoring, and metabolic applications showed emerging but heterogeneous evidence. Cuffless blood pressure estimation remains limited by calibration dependence, motion sensitivity, and poor generalizability. Remote PPG (rPPG) achieves good accuracy under controlled lighting but degrades with motion, light variability, and darker skin pigmentation. Across domains, performance was typically higher in controlled environments and attenuated in free-living settings. Common methodological limitations included small samples, inconsistent reporting of device and preprocessing details, lack of external validation, algorithm opacity, and underrepresentation of diverse populations.
Conclusions:
PPG is approaching clinical maturity for atrial fibrillation screening and resting heart-rate monitoring, while other applications remain earlier in development. Safe integration into practice requires confirmatory ECG for rhythm abnormalities, awareness of bias sources, and adherence to transparent reporting. Future progress depends on multicenter longitudinal studies, real-world validation, diverse benchmark datasets, standardized metrics, and improved reproducibility across devices and algorithms. PPG holds promise as a scalable component of digital health infrastructure when developed and evaluated with methodological rigor. Clinical Trial: PROSPERO Registration: CRD420251015845
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