Severe hypoglycaemia is associated with increased risk of adverse cardiovascular complications in adults with type 1 diabetes: risk mitigation using intermittently scanned continuous glucose monitoring

AIMS/HYPOTHESIS: It has been proposed that severe hypoglycaemia events (SHE) may increase the risk of adverse CVD complications in adults with type 1 diabetes. The aim of this study was to evaluate the risk of CVD complications following SHE in a large cohort of adults with type 1 diabetes, and to compare the risk of post-SHE CVD complications for users of intermittently scanned continuous glucose monitoring (isCGM) vs users of blood glucose monitoring (BGM). METHODS: This comparative retrospective cohort study used data from the Swedish National Diabetes Register and the Swedish National Patient Register. We identified people with type 1 diabetes who had a hospitalisation for CVD complications. Rates of hospitalisation were compared between those with an index SHE and those without, and within isCGM or BGM subgroups. The study baseline was date of the first SHE prior to the isCGM index date. RESULTS: We identified 14,829 adults with type 1 diabetes with up to 2 years of follow-up, of which 1313 had an index SHE. In the full cohort, the relative rate of hospitalisations for CVD complications was 2.06-fold (95% CI 1.48, 2.85) in those with prior SHE. Of these 1313 participants with prior SHE, 970 were using isCGM and 343 were using BGM. Hospitalisations for post-SHE CVD complications were significantly lower for isCGM users (5.40 per 100 person-years of follow-up; 95% CI 4.59, 6.31) compared with BGM control participants (14.23 per 100 person-years of follow-up; 95% CI 11.95, 16.82), which represents a 78% relative reduction in rates of post-SHE CVD complications for isCGM users (relative rate 0.22; 95% CI 0.11, 0.43; p<0.001), after adjustment for confounders. CONCLUSIONS/INTERPRETATION: In adults with type 1 diabetes, SHE is associated with an increased risk of hospitalisation for adverse CVD complications. This risk is significantly reduced in isCGM users compared with BGM control participants.