Use of the new guidelines on an earlier age threshold of 35 years for diabetes screening can identify an additional 6.3 million undiagnosed individuals with diabetes and 72.3 million individuals with prediabetes among Chinese adults: An analysis of a nationally representative survey

Background: Young-onset diabetes has been increasingly prevalent in China and most of the young patients with diabetes remain undiagnosed. Recently, the American Diabetes Association (ADA) updated their screening criteria and turned down the age threshold of diabetes screening from 45 years to 35 years, which highlighted the importance of identifying young individuals with diabetes. Herein, we aimed to evaluate the clinical relevance of updated ADA screening recommendations in Chinese adults and the metabolic features and risk factor profiles of these newly diagnosed individuals.

Study design and methods: Using a complex, multistage, probability sampling design, we analyzed data from a nationally representative sample of 98,658 Chinese adults in 2010. Participants without previously diagnosed diabetes were included into the present study. We calculated the proportion of individuals with diabetes eligible for screening and the number needed to screen (NNS) to identify one patient with diabetes by age groups.

Results: Setting an earlier age threshold of diabetes screening can identify additional 6.3 million patients with diabetes and 72.3 million individuals with prediabetes, and the proportion of identified individuals increased more in rural, underdeveloped, and central areas. The NNS in Chinese adults dropped significantly from 28 in 30-34 age group to 15 in 35-45 years of age and remained low afterwards. The undiagnosed patients with diabetes who met the new screening age threshold of ADA recommendation were characterized by younger age, lower blood pressure and blood lipids, but higher proportion of overweight and higher level of insulin resistance, and tended to have an unhealthy diet habit, including low intake of fruits and vegetables and high intake of sugar-sweetened beverages, compared to those aged over 45 years.

Conclusions: The new age threshold of 35 years for diabetes screening would reduce the proportion of undiagnosed diabetes with high cost-effectiveness, given the NNS for a positive test result was much lower in 35-45 age group comparing to the lower age group in Chinese adults.