INS and diabetes mellitus: IAH develops in approximately 20%–40% of individuals with type 1 diabetes mellitus and 15%–20% of insulin-treated individuals with type 2 diabetes, and lower intensity of symptoms and higher prevalence of IAH increase with longer duration of diabetes.3–5 Earlier studies showed that IAH is associated with an increased risk of asymptomatic and severe hypoglycemia6–9 and has a strong negative impact on quality of life.2 10 Furthermore, cognitive impairment, seizure, coma and even death may occur.11–13