Accuracy of Continuous Glucose Monitoring in Adults with Type 1 Diabetes Admitted to Hospital: A Real-World Multicenter Observational Study.

Introduction: Continuous glucose monitoring (CGM) use in people with type 1 diabetes (T1D) is revolutionizing management. Use of CGM in hospital is poised to transform care, however routine use is not currently recommended due to lack of accuracy validation in acute care, including in people with T1D. We aimed to determine real-world CGM accuracy in hospitalized adults with T1D. Materials and Methods: In this multicenter retrospective observational study, we compared CGM interstitial fluid glucose with reference blood glucose (capillary/whole-blood point-of-care [POC], blood gas [GAS]) in adults with T1D requiring multiday admissions during 2020-2023 across three health services in Australia. Patients requiring dialysis or admitted under pediatric/obstetric/palliative care/psychiatry units were excluded. CGM accuracy was assessed by comparison with time-matched (±5 min) reference glucose measures, utilizing median absolute relative difference (ARD), mean ARD (MARD), and consensus error grid (CEG) analysis. Results: In total, 2,199 CGM-reference glucose pairs from 214 admissions (146 patients) were assessed. Overall, mean (SD) ARD was 12.8% (13.1) and median (IQR) ARD was 9.4% (3.7-17.7). MARD for CGM-POC pairs was 12.3%; MARD for CGM-GAS pairs was 14.3%. In CEG analysis, 99.3% of glucose pairs were within zones A/B. Accuracy was lower in critical care compared with noncritical care wards (MARD 16.1% vs. 12.0%, P < 0.001). Conclusions: In this real-world multicenter study, CGM glucose agreed well with reference blood glucose, suggesting modern CGM devices could be safely and effectively used in hospitalized adults with T1D. Further prospective studies of CGM accuracy with newer generation devices across different scenarios will further elucidate inpatient CGM accuracy and safety.