Does the type of insulin used in hospital matter? An audit of inpatient glycaemic control in patients with insulin-treated Type 2 diabetes

Background: The importance of inpatient glycaemic control has gained prominence in recent times. How to achieve such control and with which insulin regime is controversial. Methods: Successive acute medical inpatients with a co-existing diagnosis of insulin-treated Type 2 diabetes were studied. Exclusion criteria were admission due to a direct complication of diabetes or to intensive care. Days on intravenous insulin were not included for analysis (except for length of stay). Data were collected from inpatient glycaemic charts for Capillary Glucose (CG) readings and type of insulin used. Results: 96 patients were studied (age 65.2 7 12.8 (SD) years), comprising 679 inpatient days. Median length of stay was 6 days (IQR 3 to 10). Mean glucose on days 1, 2 and 3 were 11.1 7 4.5, 10.4 7 3.6 and 9.9 7 3.6 mmol/l respectively. Insulin type was: basal alone n 5 16, rapid only n 5 7, basal bolus n 5 35, mixed n 5 37, other n 5 1. The mean daily glucose concentrations; 9am; pre- dinner; and bedtime glucose were no different in any of the insulin treatment groups. Hypoglycaemia (o4 mmol/l) occurred on 72 days (11%). There were 233 (34%) ‘good’ glycaemic days (4 readings; no CG o4, no more than one value 411 mmol/l). Hypoglycaemia did not occur more frequently on days with hyperglycaemia suggesting no ‘swinging’ of glycaemia. Conclusions: None of the insulin types had an advantage of better glycaemic control in medical inpatients with Type 2 diabetes. Glycaemic control was suboptimal in all the groups and the lack of swinging glycaemia suggests that attention should focus on optimising the insulin dose, rather than changing the insulin regime.