Insulin injection sites in diabetes--a neglected area?

Lipohypertrophy in China: Prevalence, Risk Factors, Insulin Consumption, and Clinical Impact

BACKGROUND

Lipohypertrophy (LH) is a complication of insulin therapy. We assessed LH prevalence, risk factors, insulin usage, and clinical and health economic effects in China.

METHODS

In four cities, 401 adult patients injecting insulin ≥1 year were surveyed for diabetes/insulin injection history and practices, pen needle reimbursement (PNR), and health resource utilization, followed by structured examination and HbA1c testing. Differences between those with and without LH were evaluated by Student's t-test or the Wilcoxon rank sum test. Insulin costs were calculated.

RESULTS

Patients were 59.6 ± 11.5 years old; 50% male; 93.5% type 2 diabetes. LH prevalence was 53.1%. Compared to those without LH, patients with LH had higher body mass index (BMI; 26 vs. 24.8 kg/m²) and HbA1c (8.2% vs. 7.7% [66 vs. 61 mmol/mol]), took 11 IU (0.13 IU/kg or 31.7%) more insulin costing $1.4 versus $1.0 (RMB 9.5 vs. 6.8) daily, reused PNs more times, and had less PNR (all P ≤ 0.003). LH patients correctly rotated injection sites less often (67.6% vs. 92.3%, P < 0.0001). By stepwise logistic regression, BMI, needle reuse frequency, and PNR remained modestly associated with LH prevalence (odds ratios [OR] <1.9; P ≤ 0.03); weight-adjusted insulin dose and incorrect site rotation showed ORs of nearly 7 and 8.4, respectively (P ≤ 0.001). Extrapolated to 9 million insulin-injecting patients in China and adjusted for therapy adherence, LH-related excess annual insulin consumption cost is estimated at nearly $297 million (RMB 2 billion).

CONCLUSIONS

LH is common in China and associated with worse glycemic control, despite nearly one-third greater insulin consumption, with large cost implications. Proper injection technique education may reduce LH prevalence.

Metabolic consequences of incorrect insulin administration techniques in aging subjects with diabetes

Only few insulin-treated (IT) people with diabetes mellitus (DM) reach the target due to poor compliance and/or to sedentary lifestyle and/or to inadequate treatment regimen. The latter may be also brought about by often overlooked factors including insulin injection into altered skin areas, often brought about by incorrect habits, namely needle reutilization or poor compliance to the suggestion to continuously rotate skin injection areas. The aim of our study was to evaluate the rate of skin lesions within the sites commonly used for insulin injection in our IT DM patients and to verify whether a short-acting insulin analogue yielded different metabolic effects when injected in altered vs. normal skin areas. One hundred and eighty well-trained IT people with type 1 and type 2 DM (64 ± 15 years of age) consecutively referring to our unit underwent a standard clinical examination involving an accurate skin inspection protocol meant at looking for any alterations eventually affecting all possible injection sites, including bruising, multiple needle pricks and lipodystrophic nodules (LN). They were also tested for HPLC HbA1c determination and asked to fill in a standard questionnaire on injection habits. Furthermore, seven male, T1DM glulisine-glargine basal-bolus-treated patients in this group were randomly injected 10 IU glulisine into either normal skin (NS) or an LN by a nurse before a standard, 405 kcal breakfast, for blood glucose and free insulin determination at 0, 30, 45, 60, 75, 90, 120 and 150 min. More lesions were found in people over sixty (P < 0.01) and in women (P < 0.05). A higher prevalence of HbA1c >7.5% was found in patients with lesions (with an O.R. of 3.74) and further confirmed by data obtained from head-to-head comparison of insulin injection into an LN and NS. In fact, injection into an LN proved to impair and slow down insulin absorption, resulting in a higher absolute value and a larger variability of blood glucose levels than those observed by utilizing NS. This suggests us to pay more attention to all aspects of patient-team relationship to try and obtain good metabolic control in all people with diabetes and even more in the elderly.

Diabetic lipohypertrophy treated with suction-assisted lipectomy

OBJECTIVES

To investigate the effectiveness of liposuction as treatment for lipohypertrophy in insulin-treated diabetic patients.

DESIGN

Open clinical study.

SETTING

Norwegian National Hospital, Oslo.

SUBJECTS

Five consecutive diabetic patients operated on for insulin-induced lipohypertrophy.

INTERVENTIONS

Syringe-assisted liposuction under local anaesthesia.

MAIN OUTCOME MEASURES

Change in contours assessed by pre- and postoperative photographs, and by the patients' and surgeon's evaluations according to a four-point graded scale.

RESULTS

Good or excellent results were obtained in all patients. Small surface irregularities were seen in two patients who had large volumes of fat removed from the proximal anterior thighs. Apart from this no side-effects or complications occurred.

CONCLUSIONS

Insulin-induced lipohypertrophy ('insulin tumours') can be treated successfully with liposuction.

Morphology of palpably abnormal injection sites and effects on absorption of isophane(NPH) insulin

The absorption of isophane(NPH) insulin (Human Insulatard) from palpably abnormal thigh insulin injection sites was determined in 10 C-peptide negative diabetic patients. Absorption was compared with a control day study when the insulin was injected into normal thigh. Standard meals were given 30 and 240 min after the injection. Within 2 weeks the tissue morphology and adipose tissue depths at both injection sites were assessed by ultrasound scanning. Absorption of isophane(NPH) insulin was markedly defective from the abnormal compared with the normal injection sites (area under the free insulin curve to 10 h 115 +/- 15 vs 188 +/- 21 mU l-1 h; p less than 0.01). The area under the blood glucose curve from 270 min to the end of the study at 600 min was significantly greater after injection into the palpably abnormal injection site compared with normal thigh (80.4 +/- 5.2 vs 61.2 +/- 7.0 mmol l-1 h; p less than 0.05) representing a 22% improvement in blood glucose control on the normal injection site afternoon. The depth of abnormal injection site tissue was significantly greater than the depth of adipose tissue at the control site (17 +/- 6 vs 5 +/- 4 mm; p less than 0.001) and considerable disruption of the normal anatomy observed. These results demonstrate defective absorption of isophane(NPH) insulin from palpably abnormal injection sites and describe the morphology of the abnormal tissue.

Lipohypertrophy and lipoatrophy complicating treatment with highly purified bovine and porcine insulins

Lipoatrophy and lipohypertrophy were the most frequently reported local complications of conventional insulin therapy. Early reports following the introduction of highly purified insulins suggested a reduction in the frequency of lipohypertrophy and lipoatrophy. Since highly purified insulins have been in common usage for 10 years, the present frequency of these complications was assessed in a study of 281 insulin treated diabetics. Lipohypertrophy was recorded in 76 (27.1%) patients including 3 with associated lipoatrophy. Lipoatrophy was found in 7 (2.5%) cases (3 porcine and 4 bovine insulin treated), 4 of which had only ever used highly purified insulins. Despite the introduction of highly purified insulins, lipohypertrophy and lipoatrophy remain prevalent in insulin treated patients. This common complication may be limited by routinely inspecting injection sites.

Paradoxical lipodystrophic changes due to conventional bovine and highly purified porcine/bovine insulins

A 78-year-old woman developed marked insulin lipoatrophy due to conventional bovine insulin injected into the upper limbs. Changing to a combination of highly purified porcine/bovine insulins injected into the lower limbs resulted in the opposite effect, namely insulin-induced lipohypertrophy. Use was then made of this effect by injecting the highly purified insulins into the atrophied upper limb injection sites with resultant improvement in these wasted areas over the next 10 months.