Dose accuracy of SoloSTAR and FlexPen as assessed in a clinical setting

This study aimed to compare the accuracy of SoloSTAR(sanofi-aventis, Paris, France) and FlexPen (Novo Nordisk, Bagsvaerd, Denmark) to deliver doses of insulin when used by insulin/device-naive people attending a local healthcare practice.

For the determination of dose accuracy, SoloSTAR containing insulin glargine (lot 672) and FlexPen containing insulin aspart (lot SH70557) were used for all tests. The participants were given instruction by an independent monitor on how to use the pens. To be consistent, users were trained to hold the pens in situ for 10 s at the end of injection to ensure that the full dose was injected. Forty-eight subjects performed three dose deliveries of 20 units (into a sponge) with each pen type. The method of injecting into a sponge aimed to mimic real-life practice; this approach is commonly used to ensure the patient has a correct injection technique before the patient self-administers the injection.

The delivery (n = 144) of individual doses of 20 units was not statistically different (P = 0.187) between SoloSTAR (mean +/- SD, 19.75 +/- 0.30 units) and FlexPen (19.80 +/- 0.33 units). In total, 2% of doses from both devices were <19 units; 98% were within 19-21 units.

Both SoloSTAR and FlexPen were similarly accurate when used by device-naive subjects to deliver 20-unit doses of insulin. This is likely to have beneficial clinical effects in terms of glycemic control, as well as improved patient confidence that insulin pens accurately deliver doses of insulin.