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Undiagnosed Diabetes Rates Decline

A lower percentage of type 2 diabetes cases are going undiagnosed than was the case in the past couple of decades, researchers found…. 

In an analysis of NHANES data, Elizabeth Selvin, PhD, MPH, of Johns Hopkins Bloomberg School of Public Health, and colleagues found that only 11% of the national burden of diabetes was attributable to undiagnosed cases, compared with 16% about 15 years earlier.

"Despite considerable increases in total diabetes cases over the past 2 decades, trends in undiagnosed diabetes have remained fairly stable," Selvin and colleagues wrote, which "probably reflects improvements in screening and diagnosis."

The researchers looked at data from the National Health and Nutrition Examination Survey (NHANES) 1988-1994 and 1999-2010, selecting about 43,500 patients who attended the clinical examination and had HbA1c data available.

Selvin and colleagues used calibrated HbA1c levels to define undiagnosed diabetes and prediabetes.

In 2010, about 21 million adults had confirmed diabetes, as defined by calibrated HbA1c of 6.5% and up, and the prevalence had increased during those study periods, from 6.2% in the earliest period to 9.9% by the latest. The prevalence of prediabetes also rose over course of the study, from about 6% to 12%, they reported. On the other hand, prevalence of undiagnosed diabetes remained stable during that time. Only 11% of total diabetes in 2005-2010 was undiagnosed diabetes, compared with 16% in 1988-1994.

"The proportion of undiagnosed diabetes cases decreased, suggesting improvements in screening and diagnosis," they wrote. But the prevalence of undiagnosed diabetes was higher among blacks and Mexican Americans than it was among whites, they noted.

Selvin E, et al "Trends in prevalence and control of diabetes in the United States, 1988 to 1994 and 1999 to 2010" Ann Intern Med 2014; DOI: 10.7326/M13-2411.:Middlebeek RJW, Abrahamson MJ "Diabetes, prediabetes, and glycemic control in the United States: Challenges and opportunities" Ann Intern Med 2014; 160: 572-573.