Diabetes patients do not absorb insulin effectively when injecting into lipohypertrophy, confirm new studies

Two new studies provide evidence for the first time that insulin is not absorbed effectively when injected into Lipohypertrophy (LH).

LH has long been associated with poor insulin absorption; in a 2013 study, 39.1% of participants with LH had unexplained hypoglycaemia, compared to 5.9% without, but this is the first time the link has been proven.

The Glucose ‘Clamp’ study was conducted by Famulla et al, who concluded that ‘Lipohypertrophy leads to blunted, more variable insulin absorption and action’. In this study, a clamp was used to maintain blood glucose concentration for 24 hours in all subjects, followed by regular insulin injections into LH or normal tissue. When injected into LH, the insulin concentration in the blood stream was 37% lower in the first four hours and the maximum insulin concentration was 34% lower. When injected into LH, there was a 27% reduction in Glucose Infusion Rate. These results show that insulin absorption and action from LH are considerably less reliable than from healthy tissue.

Conducted by Hövelmann et al, the Mixed Meal tolerance test study saw all participants given exactly the same food meals. Prior to eating, insulin was injected into normal tissue for one meal and into LH for the other to measure blood glucose concentration and insulin absorption. Insulin activity within the first five hours was reduced by 46% when injecting into LH. Post-meal blood glucose concentrations significantly increased when injecting insulin into LH, whereas injecting into normal tissue lead to a 25% post-meal glucose reduction. Maximum blood glucose concentration was also reached 15 minutes later when injecting into LH. The study authors concluded that insulin injection into LH impairs insulin absorption leading to deterioration in after meal blood glucose control.

People with diabetes can help to avoid lipohypertrophy through good injection technique; evidence suggests that those who suffer from LH tend to fail to rotate injection sites on a regular basis, inject into small injection zones and engage in needle re-use. These aspects of good injection technique, along with the use of 4mm pen needles, also help to reduce erratic insulin absorption and glycaemic variability.