- Ketan Dhatariya, consultant in diabetes and endocrinology
- 1Elsie Bertram Diabetes Centre, Norfolk and Norwich University Hospitals NHS Foundation Trust, Norwich NR4 7UY, UK
- Correspondence to: K Dhatariya
- Accepted 20 December 2012
Two large scale randomised controlled trials in the 1990s were the first such trials to show that the control of blood glucose helped to prevent long term complications in people with types 1 and 2 diabetes.1 2 Glucose concentrations can rise not only in people with pre-existing diabetes, but also, for short periods, in people without the condition—in particular, during times of acute illness, when it is called stress hyperglycaemia.3 As discussed below, data show that raised blood glucose concentrations in people with and without a previous diagnosis of diabetes are associated with short term harm. However, whereas the benefits of good glycaemic control over a long period in people with diabetes are well established, uncertainty remains about whether treating transient hyperglycaemia, in particular in hospital inpatients, makes any difference to short term outcomes.
Sometimes the question is moot and treating hyperglycaemia is crucial—for example, in diabetic ketoacidosis or hyperosmolar hyperglycaemic states4 or in patients who are symptomatic from their hyperglycaemia. This article does not discuss these states.
What is the evidence of the uncertainty?
I searched PubMed, the Cochrane Library, and Clinical Evidence to identify publications that concerned the outcomes of hyperglycaemia in hospital inpatients and those that dealt with treating the hyperglycaemia. Since the two trials in the 1990s,1 2 other studies have also shown that hyperglycaemia in inpatients with and without pre-existing diabetes is associated with poor outcomes. However, most trials were observational, with only a few randomised controlled trials. A meta-analysis of 34 randomised control trials assessing perioperative insulin infusion in 2192 surgical patients concluded that “perioperative insulin infusion may reduce mortality but increases hypoglycaemia in patients who are undergoing surgery.”5 However, only 14 of these studies included patients with diabetes, with 13 studies excluding them and …