Care recommendations
The arm as an injection site
Diabetes UK is aware that there is debate as to the suitability of using the arms as an injection site. This is based on the assumption that it is difficult to inject subcutaneously in this area, due to the relatively thin layer of subcutaneous adipose tissue, leading to a high number of intramuscular injections.
Intramuscular injections have been associated with a higher risk of hypoglycaemia* and the potential for less stable control.
This problem is avoided in other injection sites by the ‘pinch up’ technique, with the injection given at a 45 degree angle, if the person has little subcutaneous adipose tissue.
However, this is virtually impossible for an individual to achieve if injecting into the arm. However, with the development of shorter length needles, this problem can be reduced. Several studies have indicated that using 8mm, rather than 12.7 mm needles, can lead to an improved rate of subcutaneous injections in children with Type 1 diabetes** even when injecting into the arms. However, this certainly does not eradicate the problem as only 45.5 per cent of children, injecting into the arm with an 8mm needle, successfully injected subcutaneously rather than intramuscularly**. There is a presumption that using the shorter needles, now available, that the arms could be used more successfully.
Research into the depth of adipose tissue in the arms in adults suggests that the average thickness is 9mm in men and 15mm in women***. This would suggest that for the average adult, injecting into the arms with an 8mm needle would be successful. Lean adults would need to consider using a shorter needle or avoiding the arms.
In conclusion, Diabetes UK would suggest that the arms may be used as a site for injection provided the appropriate length of needle, and the correct technique for administration of insulin, is used. This should be individually assessed by the diabetes team. People using their arms should be encouraged to monitor their blood glucose control more regularly, to ensure that their technique is delivering the insulin appropriately. They should also be warned of the risk of hypoglycaemia following injection into the arm. Parents should be encouraged to use the ‘pinch up’ technique if using the arms as a site for their children and should use shorter needles.
*Vaag, A. et al. Intramuscular versus subcutaneous injection of unmodified insulin: consequences for blood glucose contrl in patients with Type 1 diabetes mellitus. Diabetic Medicine 7:335-342, 1990
**Tubiana-Rufi, N. et al. Short needles (8mm) reduce the risk of intramuscular injections in children with Type 1 diabetes. Diabetes Care 22:10, 1999
***Frid, A., Linden, B. Where do lean diabetics inject their insulin? A study using computed tomography. British Medical Journal 292:1638 1986