Incidence and severity of hypoglycaemia in type 2 diabetes by treatment regimen: a UK multi-site 12-month prospective observational study

AIMS: To determine the incidence and severity of self-reported hypoglycaemia in a primary care population with type 2 diabetes. The study also aimed to compare incidence by treatment regimen. MATERIALS AND METHODS: A prospective observational study in 17 centres throughout the UK. Recruitment was based on treatment regimen (metformin, sulfonylurea, insulin or incretin-based therapy). Participants were asked to keep a blood glucose diary and self-report hypoglycaemia episodes (non-severe (self-treated) and severe (requiring external help), over a 12-month period. RESULTS: 325 participants were enrolled, of whom 274 (84%) returned ≥1 monthly diary. Overall, 39% reported experiencing hypoglycaemia; 32% recorded ≥1 symptomatic episode, 36% ≥1 non-severe and 7% ≥1 severe. By treatment, incidence (events per person/year) for any hypoglycaemia type was 4.39 for insulin, 2.34 sulfonylurea, 0.76 metformin and 0.56 incretin-based. Compared to metformin, risk of non-severe hypoglycaemia was around three times higher for participants on sulfonylureas and over five times higher for those on insulin (IRR 3.02 [1.76- 5.18], p<0.001, and IRR 5.96 [3.48-10.2], p<0.001, respectively). For severe episodes, the incidence for sulfonylurea (0.09) was similar to metformin (0.07) and incretin-based (0.07); for insulin the risk remained almost five times higher than metformin (incidence 0.32; IRR 4.55 [1.28-16.20], p=0.019). CONCLUSIONS: Hypoglycaemia represents a substantial burden for people with type 2 diabetes. Sulfonylureas and insulin are both associated with a risk of reported non-severe hypoglycaemia, but only insulin with severe episodes. This suggests the importance of the continued use of sulfonylureas in appropriate patients with type 2 diabetes.