Lipohypertrophy (LH) is a common diabetes problem associated with exogenous insulin exposure in the subcutaneous tissue. LH can attenuate insulin absorption, increasing glucose variability (GV). LH conveys hazards for both: excess hyperglycaemia leading to diabetes complications; and severe hypoglycaemia, when insulin is injected into an LH free area.
Aim
To assess the impact of LH nodules on glucose variability in adults with Type 1 diabetes (T1DM).
A case-crossover study of 27 participants with T1DM and LH was conducted. LH was characterised with ultrasound. GV was assessed in two conditions using blind continuous glucose monitoring (CGM): Condition 1, usual insulin injecting behaviour; and Condition 2, injecting in LH free areas.
A total of 27 participants were enrolled, of which 15 completed the study. The median age of the participants was 32 (IQR, 35) years (range 20-71 years), with a median duration of T1DM of 14 (IQR, 13) years. In terms of the impact of LH on GV, one third of the participants demonstrated improvement in variability of >10% of time in range (4-10mmol/l), while the remainder showed no improvement, or in two cases a worsening of their GV. The findings also showed reductions in the total daily insulin dose (mean±SD -4±8.5, range -25 - +4) and increases in the number of effective bolus injections by 16.1% in Condition 2.
The interaction between LH and GV is complex and mediated by patient behaviour. In addition, the study provides data on the utility of ultrasound as a method for detecting LH.