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Original ArticleFree Preview
The members of the FLASH-UK Trial Study Group are listed in the Supplementary Appendix, available at NEJM.org.
In persons with type 1 diabetes and high glycated hemoglobin levels, the benefits of intermittently scanned continuous glucose monitoring with optional alarms for high and low blood glucose levels are uncertain.
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In a parallel-group, multicenter, randomized, controlled trial involving participants with type 1 diabetes and glycated hemoglobin levels between 7.5% and 11.0%, we investigated the efficacy of intermittently scanned continuous glucose monitoring as compared with participant monitoring of blood glucose levels with fingerstick testing. The primary outcome was the glycated hemoglobin level at 24 weeks, analyzed according to the intention-to-treat principle. Key secondary outcomes included sensor data, participant-reported outcome measures, and safety.
A total of 156 participants were randomly assigned, in a 1:1 ratio, to undergo intermittently scanned continuous glucose monitoring (the intervention group, 78 participants) or to monitor their own blood glucose levels with fingerstick testing (the usual-care group, 78 participants). At baseline, the mean (±SD) age of the participants was 44±15 years, and the mean duration of diabetes was 21±13 years; 44% of the participants were women. The mean baseline glycated hemoglobin level was 8.7±0.9% in the intervention group and 8.5±0.8% in the usual-care group; these levels decreased to 7.9±0.8% and 8.3±0.9%, respectively, at 24 weeks (adjusted mean between-group difference, −0.5 percentage points; 95% confidence interval [CI], −0.7 to −0.3; P<0.001). The time per day that the glucose level was in the target range was 9.0 percentage points (95% CI, 4.7 to 13.3) higher or 130 minutes (95% CI, 68 to 192) longer in the intervention group than in the usual-care group, and the time spent in a hypoglycemic state (blood glucose level, <70 mg per deciliter [<3.9 mmol per liter]) was 3.0 percentage points (95% CI, 1.4 to 4.5) lower or 43 minutes (95% CI, 20 to 65) shorter in the intervention group. Two participants in the usual-care group had an episode of severe hypoglycemia, and 1 participant in the intervention group had a skin reaction to the sensor.
Among participants with type 1 diabetes and high glycated hemoglobin levels, the use of intermittently scanned continuous glucose monitoring with optional alarms for high and low blood glucose levels resulted in significantly lower glycated hemoglobin levels than levels monitored by fingerstick testing. (Funded by Diabetes UK and others; FLASH-UK ClinicalTrials.gov number, NCT03815006.)
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Supported by a grant (18/0005836) from Diabetes UK; funding for the trial devices from the U.K. National Health Service (NHS); the Cambridge Biomedical Research Centre of the National Institute for Health and Care Research; and salary support (to Dr. Evans, University of Cambridge) from the NHS in the East of England through the Clinical Academic Reserve.
Disclosure forms provided by the authors are available with the full text of this article at NEJM.org.
This article was published on October 5, 2022, at NEJM.org.
A data sharing statement provided by the authors is available with the full text of this article at NEJM.org.
We thank the independent members of the trial steering committee (Drs. Rory McCrimmon, Irene Stratton, Khalida Ismail, Catrin Plumpton, Colin Green, and Raymond Agius, and Mr. Nick Cahm) and the independent data monitoring committee (Drs. Helen Murphy, Jan Bolinder, and Christina Campbell); the staff of the Manchester Clinical Trials Unit, University of Manchester, for their involvement; Dr. Ashma Krishan, Centre for Biostatistics, University of Manchester, for statistics input; Drs. Roman Hovorka and Malgorzata E. Wilinska, University of Cambridge, for allowing us to use GStat software for analysis of the sensor data and Mr. Navindu Leelarathna, University of Cambridge, for assistance with sensor-data file preparation; INPUT Patient Advocacy, Derby T1 Diabetes support group, Group for Research and Clinical Experience in Diabetes (Addenbrooke’s Hospital), and the patient and public involvement group, Manchester Diabetes Centre, for their input into the grant application; and Mr. Mohammed Majid Nazir, senior clinical trials coordinator, and the members of the Research and Innovation Department at Manchester University NHS Foundation Trust for their contribution to the trial conduct.
From the Diabetes, Endocrinology, and Metabolism Centre, Manchester Royal Infirmary, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre (L.L., W.M., N.K., M.C., H.T.), the Division of Diabetes, Endocrinology, and Gastroenterology, Faculty of Biology, Medicine, and Health (L.L., H.T.), and the Centre for Biostatistics (C.J.S., V.P.T.), the Manchester Centre for Health Economics (R.A.E., G.G.), and the Manchester Clinical Trials Unit (C.J.S., M.B.), Division of Population Health, Health Service Research and Primary Care, University of Manchester, Manchester, Wellcome Trust–Medical Research Council Institute of Metabolic Science, National Institute for Health and Care Research Cambridge Biomedical Research Centre, Cambridge University Hospitals and University of Cambridge, Cambridge (M.L.E.), Elsie Bertram Diabetes Centre, Norfolk (S.N.), Norwich University Hospitals NHS Foundation Trust, Norwich (S.N.), the Diabetes and Endocrine Centre, Ipswich Hospital, East Suffolk and North Essex NHS Foundation Trust, Ipswich (G.R.), the Adam Practice, Upton and Poole, Dorset (S.L.), the Academic Department of Diabetes and Endocrinology, Queen Alexandra Hospital, Cosham, Portsmouth (I.C.), the Institute of Immunology and Immunotherapy, College of Medical and Dental Sciences, University of Birmingham, and University Hospitals Birmingham NHS Foundation Trust, Birmingham (P.N.), Barnard Health, Barnard Health Research Limited, Portsmouth (K.B.-K.), University Hospitals of Derby and Burton NHS Foundation Trust, Royal Derby Hospital, Derby (E.G.W.), and the University of Nottingham, Nottingham (E.G.W.) — all in the United Kingdom.
Dr. Leelarathna can be contacted at [email protected] or at the Diabetes, Endocrinology, and Metabolism Centre, Peter Mount Bldg., Manchester Royal Infirmary, Oxford Rd., Manchester M13 9WL, United Kingdom.
The members of the FLASH-UK Trial Study Group are listed in the Supplementary Appendix, available at NEJM.org.
The members of the FLASH-UK Trial Study Group are listed in the Supplementary Appendix, available at NEJM.org.
October 20, 2022
N Engl J Med 2022; 387:1477-1487
DOI: 10.1056/NEJMoa2205650
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