Type 1 diabetic mellitus (T1DM) patients and approximately one-third of those with type 2 diabetes mellitus (T2DM) require exogenous insulin treatment. Lipohypertrophy (LH) is the most prevalent and well-recognized local cutaneous complication associated with insulin therapy (1, 2). The prevalence of LH in various studies ranged from 14.5 to 88% (median: 56.6%), with higher frequencies reported in subjects who repeatedly inject insulin in restricted areas (3).

Previous studies primarily focused on the associated risks and clinical impacts of LH. Several factors have been reported to affect LH development, including the period of insulin usage, rotation of insulin injection sites, frequency of needle reuse, and recurrent tissue trauma (4–6). The clinical significance of this complication is not simply cosmetic; it might also influence insulin absorption, leading to poor glycemic control (4, 7–10). Additionally, this complication may result in increased daily insulin doses and higher healthcare costs (4, 11).

Concern regarding LH development has increased among diabetes nurse educators. Insulin delivery recommendations were recently published that underscore the importance of examining injection sites for LH and the need to educate patients to inspect their own injection sites (12). Similar concepts have been stressed in Chinese national guidelines. Despite the release of injection technique guidelines and increased education, the prevalence of LH remains high. Various factors might preclude adherence to these recommendations. Few studies have focused on physicians' insights regarding LH. Physicians play central roles in diabetes management, so it is important that healthcare professionals are adequately aware of the risks of LH.

We developed a questionnaire to survey physicians in Jiangsu Province, China, to assess their insights regarding LH with regard to three aspects: awareness, knowledge, and behaviors in clinical practice.

Our survey demonstrated that LH insights of three aspects (awareness, knowledge, and behavior) were inadequate among physicians in China. Most physicians claimed to be aware of LH; however, the level differed among professional titles and hospital grades. Most physicians claimed that LH could be identified by inspection and palpation, and only half of physicians recognized the usefulness of ultrasound screening (a new screening method for LH). Although physicians had an inadequate understanding of the associated risk factors and clinical hazards of LH, it differed according to the region and hospital level. Although a management process was established at most hospitals and most physicians reported regularly inspecting insulin injection sites and educating patients about LH, these protocols appear to be insufficient at primary hospitals.

LH occurs in patients with both T1DM and T2DM and is characterized by the development of a thickened, “rubbery” lesion in the subcutaneous tissue following multiple injections performed at the same site (13). In our survey, most physicians claimed that they recognized LH as a local complication of insulin therapy. However, the results demonstrated the continued existence of insufficient LH awareness.

First, despite the increased importance of LH, no standard methods exist for defining the presence and extension of lipohypertrophic areas, which are not simple processes. Inspection and palpation are common clinical practices used to identify LH (12), but its presence can be underestimated when only these techniques are used. The reliability of this method is potentially low, with high levels of inter-clinician variation recently demonstrated by Gentile et al. (14). Ultrasound scans were recently shown to successfully identify LH with significantly increased frequency compared with inspection or palpation (15). This method can better define the extension of lipohypertrophic areas and identify the nature and severity of LH with greater detail than palpation, enabling more accurate LH grading (size, distribution, and elasticity) (16). Ultrasound is a potentially more objective diagnostic method. In our survey, only half of the physicians recognized the clinical use of ultrasound assessment for LH.

Second, previous studies have described altered insulin absorption rates at LH sites, and LH has been associated with increased glucose variability, poor metabolic control, and increased hypoglycemic episodes (1, 7–10). These outcomes have additional negative impacts on long-term outcomes, including increased daily insulin doses and higher healthcare costs (4, 11), which can have dramatic clinical, social, and economic effects. In our survey, most physicians recognized the clinical harm of LH, but approximately one-third of physicians ignored social and economic costs including increasing healthcare costs, cosmetic effects, and serious psychological burden.

Third, although the cause of LH has not been fully established, known risk factors associated with its development include high BMI, frequent needle reuse, failure to effectively rotate insulin injection sites, and the duration of insulin exposure (2, 5, 6, 10, 17). Indeed, the relationship between BMI and LH is inconsistent. Some studies indicated that higher BMI was a potential risk factor for LH (17, 18), whereas others argued that BMI was not correlated with LH occurrence (2, 10), and a few reported that lower BMI might be an LH risk factor (19). Our previous study also identified higher BMI as a risk factor (20). In our survey, most physicians recognized the associated risk factors, but only ~40% of physicians recognized all of them. Thus, physicians may have difficulty educating their patients to avoid all risk factors.

Hospitals in China are organized according to a three-tiered system (primary, secondary, or tertiary) that recognizes the abilities to provide medical care and education and conduct medical research (21). Primary hospitals are tasked with providing preventive care, minimal health care and rehabilitation services. Secondary hospitals tend to be affiliated with a medium size city, county or district. They are responsible for providing comprehensive health services, as well as medical education and conducting research on a regional basis. Tertiary hospitals are responsible for providing specialist health services, perform a bigger role with regard to medical education and scientific research and they serve as medical hubs providing care to multiple regions (22). Actually, many patients with diabetes and other chronic diseases who live in less-developed regions are treated by physicians from primary or secondary rather than tertiary hospitals. Thus, the professional skills and knowledge of internal medicine physicians should be improved in China. Our survey revealed significant variation in the awareness, knowledge, and behaviors regarding LH across different tiers. At primary hospitals, only 18.9% of physicians clearly recognized the clinical harms associated with LH, and only 54.7% of hospitals had implemented management processes. The proportions of physicians aware of LH and its diagnostic methods were significantly lower in primary hospitals than in the other tiers. Consequently, fewer physicians educated patients regarding the risks of LH. A lack of awareness of LH significance may exist among diabetes professionals at primary hospitals. Although the condition is not life-threatening, it can hamper diabetes management. Thus, increasing LH awareness among physicians; establishing standardized screening, diagnostic, treatment processes; and educating patients regularly are urgently needed at primary hospitals in China. More and more researchers pay much attention to this clinical problems of LH lesions and make efforts. Gentile et al. has demonstrated that structured education led to consistently improved metabolic results, a lower insulin requirement and decreased overall healthcare costs in insulin-treated people with type 2 diabtes (23). Furthermore, repeated refresher courses, at least at 6-month intervals, are needed (24). Thus, due to an inadequate understanding of LH, we should provided education sessions to physicians and investigate the effects.

The strengths of our study are the large sample size and the comprehensive set of questions regarding LH including diagnostic methods, clinical impacts, associated risk factors, and clinical practices. The study also has some limitations. First, the physicians' behaviors regarding LH were self-reported, so some problems could be underestimated due to the reluctance of participants to admit their errors. Second, this study only reports on the experience of Jiangsu Province, and these results cannot be generalized to patients in different regions.

Taken together, our results show that despite some improvements in recent years, LH awareness continues to be suboptimal among many physicians, highlighting the need for comprehensive and continuous education that covers all aspects associated with LH.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving human participants were reviewed and approved by the Institutional Review Board of the First Affiliated Hospital of Nanjing Medical University. The patients/participants provided their written informed consent to participate in this study.

MS initiated and led the project. YS, MS, and SZ analyzed the data. HF collected the questionnaires. JX and TY reviewed and edited the article. All authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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