Prevalence of insulin injection-induced lipohypertrophy detected by ultrasound: a systematic review and meta-analysis

Subcutaneous LH (LH) is the most common complication in patients receiving insulin injections and can lead to poor blood glucose control. Ultrasound can accurately detect LH, which helps to reveal its true prevalence, thereby increasing the emphasis on interventions and preventing its occurrence and progression to the extent possible. This study aimed to systematically evaluate the overall prevalence of LH associated with insulin injection on the basis of ultrasound detection. A comprehensive systematic search was conducted across PubMed, EMBASE, Web of Science, the Cochrane Library, China National Knowledge Infrastructure, the Wanfang Database, the China Biomedical Literature Database, and the Chinese Medical Journal Full-text Database, from January 1, 2000, to April 30, 2025, to identify relevant literature on LH detection by ultrasound. Two independent reviewers performed literature screening, quality assessment, data extraction, and cross-verification, followed by meta-analysis using Stata 16.0 software. The analysis included 18 studies encompassing 7139 patients who received diabetic insulin injections. The meta-analysis revealed a 70.5% (I2 = 98.8%, P < 0.001) overall prevalence of insulin injection-induced LH detected by ultrasound. The prevalence was 76.8% in mainland China, whereas it was 64.5% in other countries. The prevalence of type 1 diabetes was 70.8%, while that of type 2 diabetes was 58.3%. Studies conducted before 2021 reported an overall LH prevalence of 69.8%, whereas those conducted during and after 2021 reported a prevalence of 70.9%. The prevalence of LH using ultrasonic diagnostic criterion 1 was 79.2%, that using criterion 2 was 47.9%, and that using criterion 4 was 75.7%. In recent years, LH has remained prevalent among patients receiving long-term insulin injections. Administrators, health care providers, and patients should recognize LH as a public health issue that demands a systematic response. To this end, it is crucial to implement systematic training and health education, alongside active screening, early intervention, and regular follow-up. Furthermore, health care administrators and researchers should unify the ultrasound diagnostic criteria and standardize operating procedures to accurately understand the true prevalence of LH.