Lipohypertrophy in Young Patients With Type 1 Diabetes

Abnormal injection sites may complicate insulin treatment in type 1 diabetic patients, leading to delayed insulin absorption (1). The aim of this study was to document the prevalence of lipohypertrophy in young patients treated with modern insulin regimens and devices and to assess parameters influencing its development.

The injection sites of 282 children and adolescents (160 boys and 122 girls, median age 12.3 years [range 2.1–23.8]) with diabetes (duration 3.7 years [0.1–18.8]) were prospectively evaluated during outpatient clinic visits between 1 January and 31 March 2001. Findings were graded as followed: grade 0=no changes; grade 1=visible hypertrophy of fat tissue but palpably normal consistency; grade 2=massive thickening of fat tissue with higher consistency; and grade 3=lipoatrophy. HbA_1c, needle length, use of syringes, pen, or pump, number of daily injections, and insulin preparations were documented. All patients received human insulin from diabetes onset. They were taught and asked to rotate their injection sites after every injection according to a scheme (left, right thigh and/or left, right abdominal area). Data were analyzed using the Statistical Package for the Social Sciences (SPSS 9.0). Differences between the groups were calculated by the χ² test for categorical variables and the Mann-Whitney U test or Kruskal-Wallis test for two or more continuous variables, respectively. Data are presented as median (range).

A total of 135 (47.8%) of 282 patients had lipohypertrophy, 147 had no lipohypertrophy, and none had lipoatrophy at their insulin injection sites. Eighty-three patients (29.4%) had changes according to grade 1, and fifty-two (18.4%) had massive lipohypertrophy (grade 2). Patients with lipohypertrophy had significantly higher HbA_1c values (8.5% [5.1–13.3] vs. 8.7% [5.7–14.3] vs. 9.3% [5.3–16.1], P < 0.05, grade 0 vs. grade 1 vs. grade 2, respectively), more daily insulin injections (three [2–5] vs. four [2–6] vs. four [2–5], P < 0.001), and longer diabetes duration (3.0 years [0.1–18.8] vs. 4.1 years [0.3–17.3] vs. 4.3 years [0.5–13.9], P < 0.001) than those without abnormalities at injection sites. Pen usage was associated with lipohypertrophy (P=0.003). However, there was no association between lipohypertrophy at injection sites and length of needle (≤6, 8, or 12.7 mm) used by the patients (P=0.176).

These data extend previous findings in adults (2) and underline that lipohypertrophy is a very frequent problem in young patients with diabetes associated with poor glycemic control. Although a cause for these lesions is not known, the predisposing conditions are trauma to the skin and subcutaneous tissue repeated over time in the presence of insulin. Because modern insulin treatments require numerous daily injections, the results of this study highlight the need of repeated and intensive education of patients about adequate injection techniques and the necessity for routine change of the injection sites.