Intermittently scanned continuous glucose monitoring in adults with type 1 diabetes: A subgroup analysis from the FLASH-UK study.

Abstract

BACKGROUND: The FLASH-UK trial showed lower HbA1c with intermittently-scanned continuous glucose monitoring (isCGM), as compared with self-monitoring of blood glucose (SMBG), in adults with type 1 diabetes and HbA1c ≥58 mmol/mol. (≥ 7.5%). Here we present results from the pre-specified subgroup analysis for the 24-week HbA1c (primary outcome) and selected sensor-based secondary outcomes. METHODS: This was a multicentre, parallel-design, randomised controlled trial. The difference in treatment effect between subgroups (baseline HbA1c (≤75 vs >75 mmol/mol (≤9.0 vs > 9.0%), treatment modality (pump vs injections), prior participation in structured education, age, educational level, impaired awareness of hypoglycaemia, deprivation index quintile sex, ethnic group, and Patient Health Questionnaire-9 (PHQ-9) detected depression category) were evaluated. RESULTS: One hundred fifty-six participants [females 44%, mean (SD) baseline HbA1c 71 (9) mmol/mol 8.6(0.8%), age 44 (15)] were randomly assigned, in a 1:1 ratio to isCGM (n=78) or SMBG (n=78). The mean (SD) baseline HbA1c (%) was 8.7 (0.9) in the isCGM group and 8.5 (0.8) in the SMBG group, lowering to 7.9 (0.8) vs 8.3 (0.9) respectively at 24 weeks (adjusted mean difference -0.5, 95% confidence interval[CI] -0.7 to -0.3; p<0.001]. For HbA1c, there was no impact of treatment modality, prior participation in structured education, deprivation index quintile, sex or baseline depression category. The between-group difference in HbA1c was larger for younger people [a reduction of 2.7 (95%CI 0.3 to 5.0; p=0.028) mmol/mol for every additional 15 years of age]. Those with HbA1c 76-97 mmol/mol (>9.0-11.0%) had a marginally non-significant higher reduction in HbA1c of 8.4 mmol/mol (3.3 to 13.5) compared to 3.1 (0.3 to 6.0) in those with HbA1c 58-75mmol/mol (p=0.08). For "Time in range" (% 3.9 to 10 mmol/l), the difference was larger for those with at least a bachelor's degree. For "Time below range" (% <3.9 mmol/l), the difference was larger for those using injections, older people, and those with less than bachelor's degree. CONCLUSIONS: Intermittently-scanned continuous glucose monitoring is generally effective across a range of baseline characteristics.