[Introduction of a smart insulin pen in an elderly patient with type 1 diabetes mellitus].

In elderly diabetes patients with an impaired cognitive function and activities of daily living, multiple daily insulin injection (MDI) therapy is associated with poor injection rates. However, patients with insulin-dependent conditions, such as type 1 diabetes, need to continue insulin therapy. Intermittently scanned continuous glucose monitoring (isCGM) and smart insulin pens have recently emerged as devices for blood glucose management. Smart insulin pens are devices that automatically record the insulin injection time and injection units of insulin and wirelessly transfer the data to a smartphone application. We herein report an elderly patient with type 1 diabetes who was treated with a smart insulin pen.An 84-year-old woman was diagnosed with type 1 diabetes at 45 years old and had been receiving MDI therapy. She had frequent unconscious hypoglycemia and thus had isCGM introduced at 80 years old. Her Mini-Mental State Examination score was 20 points, indicating mild cognitive decline, and isCGM revealed repeated hyperglycemia due to forgetting her insulin injection and hypoglycemia due to over-dose of insulin. When she was hospitalized for diabetic ketosis at 84 years old, a smart insulin pen was introduced. Following this introduction, her family and medical staff checked her insulin records and encouraged her to perform injections. She subsequently no longer experienced hyperglycemic crisis or severe hypoglycemia.Elderly patients with type 1 diabetes often have difficulty with self-management of MDI therapy. Smart insulin pens are expected to reduce the rate of forgetting insulin injections and improve injection rates.