Premixed insulin preparations and glycaemic control in type 1 diabetes mellitus

The role of premixed insulin preparations in Type 1 DM remains unresolved. The degree of glycaemic control achieved with the use of premixed insulin p reparations in an unselected group of subjects with Type 1 DM has not previ ously been reported. We abstracted and reviewed data on 600 subjects with T ype 1 diabetes mellitus in our computer data base. 134 (23%) were taking tw o injections of premixed insulin daily. In these subjects glycaemic control as assessed by the most recent HbA1c measurement was 7.6 +/- 0.1% vs 7.4 /- 0.1% in those subjects on separate insulins, p=N.S. In those subjects aged <35 years, 62/220 (28%) used premixed insulin. HbA1c was higher in those on premixed insulin 7.8 +/- 0.2% and 7.2 +/- 0.1%, p<0 .05. This difference in HbA1c was seen only in those subjects with diabetes duration of 3 to 8 years (n=78) where HbA1c was higher in those subjects o n premixed insulin, 8.4 +/- 0.5% versus 6.9 +/- 0.2%, p<0.01. In subjects a ged >35 years, 74/318 (23%) used premixed insulin. HbA1c did not differ bet ween those using premixed insulin and those using separate insulin preparat ions, 7.5 +/- 0.2% and 7.5 +/- 0.1% respectively. We conclude that use of premixed insulin preparations achieved a similar le vel of glycaemic control as use of individual insulin preparations with the exception of patients aged less than 35 years who were 3 to 8 years follow ing diagnosis. The relatively good glycaemic control achieved may make thes e preparations a useful alternative to multiple injection therapy for many patients with Type 1 DM.