Real-World Evaluation of a Near-Infrared Spectroscopy–based Noninvasive Glucose Monitoring Device in Adults With Type 2 Diabetes

BACKGROUND: Self-monitoring of blood glucose remains widely used in many individuals with type 2 diabetes (T2D), although the burden of capillary testing often limits the frequency of measurements. Noninvasive technologies may improve glucose monitoring. This study evaluated the analytical performance and applicability of a near-infrared spectroscopy-based noninvasive glucose monitoring device. METHODS: In this prospective, open-label clinical investigation, 52 adults with T2D performed 4 daily paired glucose measurements for more than 21 days using the investigational device and a reference capillary glucometer (Ascensia Contour Next). Following individualized calibration (10 paired measurements), post-calibration measurements within the 70 to 400 mg/dL range were included in the primary analysis. Accuracy was assessed using a combined mean absolute difference/mean absolute relative difference (MAD/MARD) metric, Parkes consensus error grid (CEG), and DTS error grid analyses. RESULTS: Forty-eight participants were included in the primary analysis, contributing 2,616 paired post-calibration measurements. The mean age was 58.0 ± 9.9 years, and 31.3% were female. The overall combined MAD/MARD value was 16.3, calculated by applying MAD to paired measurements with reference glucose values <100 mg/dL and MARD to paired measurements with reference glucose values ≥100 mg/dL. Overall, 69.8%, 86.3%, and 94.5% of measurements were within ±20%, ±30%, and ±40% of reference values, respectively. Parkes CEG analysis classified 69.9% of measurements in zone A, 29.1% in zone B, 1.0% in zone C, and none in zones D or E. Accuracy improved after the first week. No device-related adverse events were reported. CONCLUSION: The device demonstrated a favorable clinical risk profile, stable analytical performance, and good safety under real-world conditions. Although analytical precision remains lower than current continuous glucose monitoring systems, its fully noninvasive design supports further development as a complementary monitoring strategy for individuals with T2D unwilling or unable to use invasive monitoring technologies. TRIAL REGISTRATION: ClinicalTrials.gov (NCT07075796).