Systematic intensive therapy in addition to continuous glucose monitoring in adults with type 1 diabetes: a multicentre, open-label, randomised controlled trial.

Background: Although continuous glucose monitor/intermittent scanning continuous glucose monitor (CGM/isCGM) is widely used for glucose monitoring, many adults with type 1 diabetes (T1D) still fail to achieve recommended glycaemic targets. We aimed to evaluate whether digital distance counselling based on CGM data could improve glycaemic control in adults with T1D and suboptimal control. Methods: In this multicentre, open-label, randomised controlled trial, adults with T1D and HbA1c ≥58 mmol/mol, already using CGM/isCGM with insulin therapy (multiple daily injections or pump), were enrolled across eight sites in Sweden and Norway. Participants were allocated (1:1) via a minimisation algorithm to receive either systematic intensive therapy (SIT) or conventional therapy (CT). The SIT group received weekly distance counselling, including CGM interpretation, if mean glucose was ≥8·4 mmol/L, during an 18-week intervention period. The control group attended two clinical visits during this period. The primary outcome was change in HbA1c from baseline to 18 weeks. Adverse events of special interest (AESI; severe hypoglycaemia or diabetic ketoacidosis) were assessed in the safety population. This trial is registered at clinicaltrials.gov number NCT03474393. Findings: 117 participants were enrolled and randomised (59 SIT, 58 control). At 18 weeks, mean (SD) HbA1c decreased by -10·7 (9·4) mmol/mol (-0·98% [0·86]) in the SIT group compared with -2·4 (8·4) mmol/mol (-0·22% [0·77]) in CT, resulting in an adjusted mean difference of -8·3 mmol/mol (95% CI -11·2 to -5·5), equivalent to -0·76% (95% CI -1·02 to -0·50%; Interpretation: SIT improves glycaemic control in adults with T1D using CGM/isCGM who are not achieving recommended glycaemic targets, without evidence of safety concerns. These findings highlight the critical role of structured, individualised interventions in addressing persistent glycaemic management deficits and advancing clinical outcomes in this population. Funding: The study was supported by the Swedish state, Region Västra Götaland, and the Swedish Diabetes Foundation.