Authors: Marcus Lind, Arndís F Ólafsdóttir, Irl B Hirsch, Jan Bolinder, Sofia Dahlqvist, Aldina Pivodic, Jarl Hellman, Magnus Wijkman, Erik Schwarcz, Henrik Albrektsson, Tim Heise, William Polonsky
Abstract
Objective: Continuous glucose monitoring (CGM) reduces HbA1c and time spent in hypoglycemia in people with type 1 diabetes (T1D) treated with multiple daily insulin injections (MDI) when evaluated over shorter time periods. It is unclear to what extent CGM improves and helps to maintain glucose control, treatment satisfaction, diabetes distress, hypoglycemic concerns, and overall well-being over longer periods of time.
Research design and methods: The GOLD trial was a randomized crossover trial performed over 16 months of CGM treatment in people with T1D treated with MDI. People completing the trial (n = 141) were invited to participate in the current SILVER extension study in which 107 patients continued CGM treatment over 1 year along with the support of a diabetes nurse every 3 months.
Results: The primary end point of the change in HbA1c over 1.0-1.5 years of CGM use compared with previous self-monitoring of blood glucose during GOLD showed a decrease in HbA1c of 0.35% (95% CI 0.19-0.50, P < 0.001). Time spent in hypoglycemia <3.0 mmol/L (54 mg/dL) and <4.0 mmol/L (72 mg/dL) decreased from 2.1% to 0.6% (P < 0.001) and from 5.4% to 2.9% (P < 0.001), respectively. Overall well-being (World Health Organization 5-item well-being index, P = 0.009), treatment satisfaction (Diabetes Treatment Satisfaction Questionnaire, P < 0.001), and hypoglycemic confidence (P < 0.001) increased, while hypoglycemic fear (Hypoglycemia Fear Survey-Worry, P = 0.016) decreased and diabetes distress tended to decrease (Problem Areas in Diabetes Scale, P = 0.06). From randomization and screening in GOLD, HbA1c was lowered by 0.45% (P < 0.001) and 0.68% (P < 0.001) after 2.3 and 2.5 years, respectively.
Conclusions: The SILVER study supports beneficial long-term effects from CGM on HbA1c, hypoglycemia, treatment satisfaction, well-being, and hypoglycemic confidence in people with T1D managed with MDI.