Are you aware that type 2 diabetes mellitus (T2D) affects approximately 537 million adults worldwide, including 37.3 million in the USA? That is over 10% of the U.S. population! Approximately 79% of the people worldwide with T2D are underserved, underrepresented, impoverished, in lower socioeconomic communities, and in developing countries. Furthermore, the worldwide prevalence of T2D is expected to reach an astonishing 783 million by 2045.1–8
Even more shocking is that approximately 50% (232 million) of those people with T2D worldwide are unaware and undiagnosed! This is a major problem since, when T2D is finally detected, at the time of diagnosis, nearly one-half already have one or more irreversible complications resulting in an at least $966 billion global economic burden.
Also, a vast 81% with prediabetes (PreD), more than 77 million in the USA, are undiagnosed and unaware. However, in PreD, earlier lifestyle modifications reduce the risk of developing T2D by greater than 50%. These high numbers of undiagnosed people may be secondary to the lower accuracy of current screening methods in certain conditions and specific populations.
T2D leads to multiple costly serious end-organ complications, including being the leading cause of both end-stage renal disease and non-traumatic lower extremity amputations. Earlier detection is critical as earlier effective glycemic management reduces the risk of associated ophthalmologic, renal, and neurologic diseases by 40%. The urgency of this important matter has even prompted the United States Preventive Services Task Force to update guidelines in 2021 to help improve earlier T2D and PreD detection.1,3,4,9,10
Given its advantages over MRI, including low cost and portability, musculoskeletal (MSK) ultrasound (US) utilization, especially shoulder US, has significantly increased over the past few decades. Shoulder US is often performed on patients with T2D, given the high prevalence of T2D in society and the increased risk of rotator cuff pathology and adhesive capsulitis in individuals with T2D.9,10
As MSK US use increases, a unique opportunity arises for detecting T2D in those unaware, undiagnosed, and presenting for (seemingly) unrelated care. It is our experience and confirmed in our prior publications9,10 that the incidental detection of a hyperechoic deltoid muscle, on routine shoulder US (Figure 1), has on many occasions resulted in the incidental identification of undiagnosed T2D and even PreD. This abnormality was seen in those with and without obesity. Also, in those uncertain of their T2D status or told they were ‘borderline’, most were not treated, despite having this characteristic US deltoid muscle abnormality. Initial experiments also suggest that the hyperechoic deltoid muscle appearance may predate the elevation of HbA1c levels.
Skeletal muscle insulin resistance is thought to be the primary defect in T2D development, often occurring decades before β-cell failure and apparent metabolic dysfunction.11 Could this earlier-identified skeletal muscle US abnormality represent the noninvasive detection of early muscle insulin resistance and dysfunction, prior to clinically apparent metabolic dysfunction?
We continue to study this novel sonographic abnormality prospectively, including using histologic analyses. We expect our studies will help elucidate this US skeletal muscle abnormality, which could represent the earlier detection of muscle insulin resistance and dysfunction. This could initiate further studies on earlier noninvasive T2D detection, prevention, treatment, and targeted therapies for potential reversal.
1. International Diabetes Federation. IDF diabetes atlas [Internet]. 10th ed. Brussels, Belgium: International Diabetes Foundation; 2021 [cited October 17, 2023].
2. Centers for Disease Control and Prevention. National Diabetes Statistics Report website. [Internet]. Atlanta (GA): Centers for Disease Control and Prevention, U.S. Department of Health and Human Services; 2022 [updated June 29, 2022; cited October 17, 2023].
3. National Center for Chronic Disease Prevention and Health Promotion, Center for Disease Control and Prevention. Cost-effectiveness of diabetes interventions [Internet]. Atlanta (GA): Centers for Disease Control and Prevention; 2022 [updated December 1, 2022; cited October 17, 2023].
4. US Preventive Services Task Force, Davidson KW, Barry MJ, Mangione CM, et al. Screening for prediabetes and type 2 diabetes: US Preventive Services Task Force recommendation statement. JAMA 2021; 326:736–743. PMID: 34427594.
5. Boyle JP, Honeycutt AA, Narayan KM, et al. Projection of diabetes burden through 2050: impact of changing demography and disease prevalence in the U.S. Diabetes Care 2001; 24:1936–1940. PMID: 11679460.
6. Lin J, Thompson TJ, Cheng YJ, et al. Projection of the future diabetes burden in the United States through 2060. Popul Health Metr 2018; 16(1):9. PMID: 29903012; PMCID: PMC6003101.
7. Rowley WR, Bezold C, Arikan Y, Byrne E, Krohe S. Diabetes 2030: insights from yesterday, today, and future trends. Popul Health Manag 2017; 20(1):6–12. PMID: 27124621; PMCID: PMC5278808.
8. National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health. Diabetes [Internet]. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2021 [cited October 17, 2023].
9. Soliman SB, Rosen KA, Williams PC, et al. The hyperechoic appearance of the deltoid muscle on shoulder ultrasound imaging as a predictor of diabetes and prediabetes. J Ultrasound Med 2020; 39:323–329. PMID: 31423604. https://onlinelibrary.wiley.com/doi/10.1002/jum.15110.
10. Rosen KA, Thodge A, Tang A, Franz BM, Klochko CL, Soliman SB. The sonographic quantitative assessment of the deltoid muscle to detect type 2 diabetes mellitus: a potential noninvasive and sensitive screening method? BMC Endocr Disord 2022; 22(1):193. PMID: 35897066.
11. DeFronzo RA, Tripathy D. Skeletal muscle insulin resistance is the primary defect in type 2 diabetes. Diabetes Care 2009; 32(Suppl 2):S157–S163. PMID: 19875544; PMCID: PMC2811436.
Steven B. Soliman, DO, RMSK, FAOCR, is an associate professor and musculoskeletal radiologist at the University of Michigan.
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