Rate of Undiagnosed Diabetes in the United States

The percentage of adults with undiagnosed diabetes in the United States is lower than previously estimated, according to a cross-sectional study published in the Annals of Internal Medicine.¹

The common belief that up to one-third of all diabetes cases remain undiagnosed may be overestimated due to epidemiological studies that do not use confirmatory testing.^2-7 Researchers reviewed data from the Third National Health and Nutrition Examination Survey conducted from 1988 to 1994 (n=7385) and 4-year survey cycles from 1999 to 2014 (n=17,045) to calculate estimates of undiagnosed diabetes in the United States. Elevated levels of fasting glucose (≥7.0 mmol/L [≥126 mg/dL]) and hemoglobin HbA_1C (≥6.5%) in people without diagnosed diabetes was used to define cases of confirmed undiagnosed diabetes.

The percentage of total diabetes cases that were undiagnosed decreased from 16.3% in 1988-1994 to 10.9% in 2011-2014, while the prevalence of total (diagnosed and confirmed undiagnosed) diabetes increased from 5.5% (9.7 million adults) to 10.8% (25.5 million adults) in these two time periods, respectively.

Overweight or obese adults, older adults, racial/ethnic minorities (including Asian Americans), and adults without health insurance or access to health care were more likely to have undiagnosed diabetes.

The percentage of undiagnosed diabetes cases is a critical public health indicator of efforts related to diabetes screening and diagnosis. This study demonstrated that, overall, most cases of diabetes are being identified through current screening and diagnostic practices.

“Our study demonstrates the importance of using a definition of undiagnosed diabetes in epidemiologic studies that is more consistent with clinical practice to derive accurate population estimates of the burden of undiagnosed diabetes,” concluded the researchers. 

References

1. Selvin E, Wang D, Lee AK, Bergenstal RM, Coresh J. Identifying trends in undiagnosed diabetes in U.S. adults by using a confirmatory definition: a cross-sectional study [published online October 24, 2017]. Ann Intern Med. doi: 10.7326/M17-1272.
2. Centers for Disease Control and Prevention. 2014 National Diabetes Statistics Report. www.thefdha.org/pdf/diabetes.pdf. Accessed October 31, 2017.
3. Centers for Disease Control and Prevention (CDC). National Diabetes Statistics Report, 2017. Accessed October 31, 2017.
4. Menke A, Casagrande S, Avilés-Santa ML, Cowie CC. Factors associated with being unaware of having diabetes. Diabetes Care. 2017;40:e55-e56.
5. Selvin E, Zhu H, Brancati FL. Elevated A1C in adults without a history of diabetes in the U.S. Diabetes Care. 2009;32:828-833.
6. Selvin E, Parrinello CM, Sacks DB, Coresh J. Trends in prevalence and control of diabetes in the United States, 1988-1994 and 1999-2010. Ann Intern Med. 2014;160:517-525.
7. Menke A, Casagrande S, Geiss L, Cowie CC. Prevalence of and trends in diabetes among adults in the United States, 1988-2012. JAMA. 2015;314:1021-1029.