# Impact of continuous glucose monitoring on glycaemic risk index in adults with type 1 diabetes using multiple daily insulin injections in the GOLD trial

## TL;DR

Switching from blood glucose monitoring to continuous glucose monitoring significantly improves overall glycaemic risk in adults with type 1 diabetes.

## Contribution

The study demonstrates that GRI is more responsive to treatment changes than TIR and highlights its potential as a clinical endpoint.

## Key findings

- Transitioning to CGM reduced GRI by 9.8 units, with significant decreases in both hypoglycaemia and hyperglycaemia.
- GRI improved or remained stable in 85.4% of participants and showed stronger treatment response than TIR.
- Psychosocial traits like thoroughness correlated with better hypoglycaemia risk reduction.

## Abstract

Continuous glucose monitoring (CGM) has significantly improved glycaemic management in individuals with diabetes. The Glycaemia Risk Index (GRI) is a composite metric based on CGM data that provides a comprehensive evaluation of glycaemic quality, incorporating both hypoglycaemia and hyperglycaemia. This study evaluated the impact of transitioning from self-monitoring of blood glucose (SMBG) to CGM on GRI in adults with type 1 diabetes (T1D) using multiple daily injection (MDI) insulin therapy.

Secondary analyses were conducted in 125 adults with T1D from the randomised GOLD trial. Participants alternated between CGM and SMBG for two 26-week periods, separated by a 17-week wash-out. The GRI was calculated on a 0–100 scale from CGM data and categorised into five risk zones. Associations between baseline characteristics and participant-reported outcomes such as diabetes-related behaviours, lifestyle, psychological characteristics, and changes in GRI were also explored.

Transitioning from SMBG to CGM significantly reduced the overall GRI by 9.8 units (95% CI −13.3, −6.3), with decreases in both hypoglycaemia (–1.8, 95% CI −2.4, −1.2) and hyperglycaemia (–2.8, 95% CI −5.3, −0.4) components. GRI zone classification was maintained or improved in 85.4% (105/123, P <.001) of participants. The GRI correlated moderately with TIR (r = –0.47, 95% CI −0.60, −0.32), but standardised effect sizes were larger for GRI than for TIR (–0.5 [95% CI –0.72, –0.34] vs. 0.2 [95% CI 0.00, 0.37]). Exploratory analyses suggested that self-reported psychosocial traits influenced GRI changes: thoroughness was linked to greater reductions in hypoglycaemia risk, whereas distractibility, self-described laziness, and carbohydrate counting training were associated with smaller improvements.

Switching from SMBG to CGM significantly improved GRI in adults with T1D on MDI therapy. Compared with TIR, GRI demonstrated greater responsiveness to treatment-related changes. As a composite metric that integrates both hypo- and hyperglycaemia, GRI may serve as a valuable endpoint for evaluating interventions and as a complementary measure in clinical practice.