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

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

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.

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).

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.