Changes in the glycaemia risk index and its association with other continuous glucose monitoring metrics after initiation of an automated insulin delivery system in adults with Type 1 Diabetes

Abstract

Aim: To evaluate the glycaemia risk index (GRI) and its association with other continuous glucose monitoring (CGM) metrics after initiation of an automated insulin delivery (AID) system in patients with type 1 diabetes (T1D). Materials and Methods: Up to 90 days of CGM data before and after initiation of an AID system from 185 CGM users with T1D were collected. GRI and other CGM metrics were calculated using cgmanalysis R software and were analysed for 24 hours, for both night-time and daytime. GRI values were assigned to five GRI zones: zone A (0-20), B (21-40), C (41-60), D (61-80) and E (81-100). Results: Compared with baseline, GRI and its components decreased significantly after AID initiation ( GRI: 48.7 +/- 21.8 vs. 29 +/- 13; hypoglycaemia component: 2.7 +/- 2.8 vs. 1.6 +/- 1.7; hyperglycaemia component: 25.3 +/- 14.5 vs. 15 +/- 8.5; P <.001 for all). The GRI was inversely correlated with time in range before (r = similar to 0.962) and after (r = similar to 0.961) AID initiation (P <.001 for both). GRI was correlated with time above range (before: r = 0.906; after = 0.910; P <.001 for both), but not with time below range (P >.05). All CGM metrics improved after AID initiation during 24 hours, for both daytime and night-time (P <.001 for all). Metrics improved significantly more during night-time than daytime (P <.01). Conclusions: GRI was highly correlated with various CGM metrics above, but not below target range, both before and after AID initiation.