Patient description: The patient is a 24-year-old man who has had type 1 diabetes for 11 years. He presents to the emergency room with hyperglycemia and concern for possible diabetic ketoacidosis after not taking his insulin for 3 days. The patient reports that he is currently homeless and has lost his supply of insulin, syringes, glucometer, and glucose testing supplies. The patient states that at the time of his initial diagnosis with type 1 diabetes he was hospitalized with a glucose value >1000 mg/dL. At the time, he was experiencing polyuria, polydipsia, and polyphagia. He reports that he has been on insulin since the time of his diagnosis, and he has never been prescribed oral agents for diabetes management. Most recently, he has been using insulin glargine 55 units once daily, and insulin aspart sliding scale 3 times daily. The patient has had previous episodes of diabetic ketoacidosis, for which he was hospitalized. With this episode of hyperglycemia, he is not experiencing any nausea, vomiting, or abdominal discomfort, and he appears well. His lab studies showed: A1c: 11.3% Creatinine: 0.9 mg/dL with eGFR >60 mL/min Aspartate aminotransferase (AST): 17 U/L Alanine aminotransferase (ALT): 14 U/L Beta-hydroxybutyrate: 0.1 mmol/L Bicarbonate: 25 mEq/L Anion

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Hyperglycemia Critical Illness Patients are eligible for in the study if ALL the following are met: 1. At time of the patient's admission to the ICU the treating ICU specialist expects the patient will require treatment in the ICU that extends beyond the calendar day following the day of admission. 2. Patient has an arterial line in situ or placement of an arterial line is imminent (within the next hour) as part of routine ICU management  Patients will be from the study if ONE or MORE of the following are present: 1. Age < 18 years. 2. Imminent death (cardiac standstill or brain death anticipated in less than 24 hours) and the treating clinicians are not committed to full supportive care. This should be confirmed by a documented treatment-limitation order that exceeds a "not-for-resuscitation" order. 3. Patients admitted to the ICU for treatment of diabetic ketoacidosis or hyperosmolar state. 4. Patient is expected to be eating before the end of the day following admission 5. Patients who have suffered hypoglycaemia without documented full neurological recovery. 6. Patient thought to be at abnormally high risk of suffering hypoglycaemia ( e.g. known insulin secreting tumour or history of unexplained or recurrent hypoglycaemia or fulminant hepatic failure) 7. If a patient has previously been enrolled in the NICE-SUGAR Study (patients cannot be enrolled in the NICE-SUGAR Study more than once). 8. If the patient can not provide prior informed consent, there is documented evidence that the patient has no legal surrogate decision maker and it appears unlikely that the patient will regain consciousness or sufficient ability to provide delayed informed consent 9. The patient has been in the study ICU or another ICU for longer than 24 hours for this admission. There is no upper age limit for into the study unless any of the specific are present. -