Glycaemic control with continuous subcutaneous insulin infusion compared with intensive insulin injections in patients with type 1 diabetes: meta-analysis of randomised controlled trials

Objective To compare glycaemic control and insulin dosage in people with type 1 diabetes treated by continuous subcutaneous insulin infusion (insulin infusion pump therapy) or optimised insulin injections. Design Meta-analysis of 12 randomised controlled trials. Participants 301 people with type I diabetes allocated to insulin infusion and 299 allocated to insulin injections for between 2.5 and 24 months. Main outcome measures Glycaemic control measured by mean blood glucose concentration and percentage of glycated haemoglobin. Total daily insulin dose. Results Mean blood glucose concentration was lower in people receiving continuous subcutaneous insulin infusion compared with those receiving insulin injections (standardised mean difference 0.56, 95% confidence interval 0.35 to 0.77), equivalent to a difference of 1.0 mmol/l. The percentage of glycated haemoglobin was also lower in people receiving insulin infusion (0.44. 0.20 to 0.69), equivalent to a difference of 0.5%. Blood glucose concentrations were less variable during insulin infusion. This improved control during insulin infusion was achieved with an average reduction of 14% in insulin dose (difference in total daily insulin dose 0.58, 0,34 to 0.83), equivalent to 7.58 units/day. Conclusions Glycaemic control is better during continuous subcutaneous insulin infusion compared with optimised injection therapy, and less insulin is needed to achieve this level of strict control. The difference in control between die two methods is small but should reduce the risk of microvascular complications.