Undiagnosed diabetes is declining in the US

National Health and Nutrition Examination Survey (NHANES) data show that undiagnosed diabetes has declined from 16% of total diabetes cases in the early 1990s to about 10% in 2013. Unrecognized diabetes was confirmed by either fasting glucose ≥ 126 mg/dL or A1c ≥ 6.5%. 

Authors found that undiagnosed diabetes was more prevalent in older, overweight and obese patients, as well as in ethnic minorities and those without health insurance.

Although DM prevalence has steadily increased in the United States this is still good news, as proper diagnosis can lead to early intervention and control.


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Annals of Internal Medicine


October 2017

Background: A common belief is that 1/4th – 1/3rd of all diabetes cases remain undiagnosed. However, such prevalence estimates may be overstated by epidemiologic studies that do not use confirmatory testing, as recommended by clinical diagnostic criteria.

Objective: To provide national estimates of undiagnosed diabetes by using a confirmatory testing strategy, in line with clinical practice guidelines.

Setting: National Health and Nutrition Examination Survey results from 1988-1994 and 1999-2014. Participants: U.S. adults aged 20 years and older.


Confirmed undiagnosed diabetes was defined as elevated levels of fasting glucose ≥126 mg/dL and hemoglobin A1c ≥6.5% in persons without diagnosed diabetes.


The prevalence of total (diagnosed plus confirmed undiagnosed) diabetes increased from 5.5% (9.7 million adults) in 1988-1994 to 10.8% (25.5 million adults) in 2011-2014. Confirmed undiagnosed diabetes increased during the past 2 decades (from 0.89% in 1988-1994 to 1.2% in 2011-2014) but has decreased over time as a proportion of total diabetes cases.

In 1988-1994, the percentage of total diabetes cases that were undiagnosed was 16.3%; by 2011-2014, this estimate had decreased to 10.9%.

Undiagnosed diabetes was more common in overweight or obese adults, older adults, racial/ethnic minorities (including Asian Americans), and persons lacking health insurance or access to health care.


Establishing the burden of undiagnosed diabetes is critical to monitoring public health efforts related to screening and diagnosis. When a confirmatory definition is used, undiagnosed diabetes is a relatively small fraction of the total diabetes population; most U.S. adults with diabetes (about 90%) have received a diagnosis of the condition.