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 was conducted. Recruitment was based on treatment regimen (metformin alone, sulphonylurea-, 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 Three hundred and twenty-five participants were enrolled, of whom 274 (84%) returned >= 1 monthly diaries. Overall, 39% reported experiencing hypoglycaemia; 32% recorded >= 1 symptomatic, 36% >= 1 non-severe, and 7% >= 1 severe episodes. By treatment, incidence (events per person/year) for any hypoglycaemia type was 4.39 for insulin, 2.34 for sulphonylurea, 0.76 for metformin, and 0.56 for incretin-based therapy. Compared with metformin, risk of non-severe hypoglycaemia was 3 times higher for participants on sulphonylureas and > 5 times higher for those on insulin [incidence rate ratio (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 sulphonylurea (0.09) was similar to metformin (0.07) and incretin-based therapy (0.07); for insulin the risk remained almost 5 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. Sulphonylureas 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 sulphonylureas in appropriate patients with type 2 diabetes.