Found this last week at Diabetes In Control
Lede paragraph reads:
A new study showed that changes in the position of a conventional insulin pump, relative to its infusion set, can significantly impact expected insulin delivery rates. The rates depending on how the insulin pump was worn varied from 74.5% of the expected delivery upward to 123.3% of expected delivery rates.
The issue is one of gravity: whether the site is above the pump, and it has to fight gravity to send the insulin through the tubing, or whether it is below the pump and the flow of insulin is aided by gravity.
All-in-one pump designs – such as the OmniPod – are affected by the position of the reservoir relative to the body, but the difference in insulin delivery is more like 1.5% than 25% difference.
The link above should bring you directly to the article in question.
Please note that the study was supported by a grant from Insulet Corporation (Nasdaq: PODD) of Bedford, MA. Insulet manufactures OmniPod and has a vested interest in showing their devices to be more accurate than competitors’ devices.