Insulin-Related Lipohypertrophy: Ultrasound Characteristics, Risk factors, and Impact of Glucose Fluctuations

BACKGROUND Lipohypertrophy (LHT) has been suggested as an outcome of the adipogenic effects of insulin injection-related tissue trauma. It commonly occurs in the clinical setting, but the current understanding of LHT by the medical staff and diabetes patients remains insufficient; moreover, it has not garnered attention as a research topic. OBJECTIVE To investigate the ultrasound characterization of LHT, to identify the factors associated with LHT development by assessing the prevalence of LHT and compare the accuracy of clinical palpation with that of ultrasonography in LHT detection, and to further evaluate the possible impact of LHT on patients' blood glucose fluctuations. METHOD A cross-sectional study was conducted in 120 patients with type 2 diabetes. Patients' general information were obtained using a questionnaire, and the patients were evaluated for LHT by ultrasonography and clinical palpation of the abdomen. The patients were instructed to inject equal amounts of insulin in tissues with LHT and in normal adipose tissues (NATs) in two non-consecutive d in a selected week; the possible effect of LHT on patients' blood glucose fluctuations was assessed using a continuous glucose monitoring system. RESULTS LHT has characteristic ultrasonic signs. We found a high rate of missed LHT detection on clinical palpation compared with that on ultrasonography (P < 0.05). The duration of insulin treatment, rotation of injection sites, frequency of needle reuse, and number of insulin injections per day were the primary factors influencing the development of LHT (P < 0.05). Compared with NATs, LHT tissues showed extremely elevated amplitude of glycemic excursion, mean blood glucose levels, standard deviation of blood glucose levels and postprandial glucose excursion, and large fluctuations in blood glucose levels (P < 0.05). CONCLUSION Ultrasonography can more accurately detect LHT than can clinical palpation. LHT development is associated with several factors and can lead to significant fluctuations in blood glucose levels; thus, sufficient attention should be paid to investigating the underlying mechanism of LHT.