Smart Ring in Clinical Medicine: A Systematic Review

Area of Science:

• Wearable technology
• Biomedical engineering
• Digital health

Background:

• Smart rings offer continuous physiological monitoring via finger-worn sensors.
• Their clinical utility beyond sleep tracking is not well-established.
• Growing consumer adoption necessitates evaluation of clinical applications.

Purpose of the Study:

• To systematically review smart ring applications in clinical medicine.
• To assess the accuracy of smart ring measurements.
• To evaluate the impact of smart rings on clinical outcomes.

Main Methods:

• Comprehensive literature search across major databases (PubMed, Embase, Cochrane, Web of Science) up to July 2025.
• Independent study screening and data extraction by two reviewers.
• Risk of bias assessment using ROBINS-I and RoB 2.0 tools.

Main Results:

• 107 studies involving ~100,000 participants were included, split between sleep and non-sleep applications.
• High accuracy reported for heart rate (r²=0.996), heart rate variability (r²=0.980), and sleep detection (93-96% sensitivity).
• Early disease detection capabilities demonstrated for COVID-19 (2.75 days prior), IBD flares (7 weeks prior), and bipolar episodes (3-7 days prior).

Conclusions:

• Smart rings show potential as clinical tools for early disease detection.
• Algorithmic opacity, limited population diversity, and declining adherence are significant limitations.
• Further research and development are needed for widespread clinical implementation.