“Screen-and-Treat” Ineffective Against Type 2 Diabetes

Because prediabetes screening tests are often inaccurate, individual treatment interventions offered only to patients identified as high risk are unlikely to have a substantial impact on the worsening epidemic of type 2 diabetes, according to a study published in The BMJ.

For effective diabetes prevention, such “screen-and-treat” policies should be combined with population-wide public health approaches that target everyone, researchers concluded.

Their findings stem from a meta-analysis of 99 studies: 49 focused on the diagnostic accuracy of prediabetes screening tests and 50 dealt with the effectiveness of interventions in preventing type 2 diabetes onset in people with prediabetes. 

Local policymakers, researchers explained, commissioned the work. They wanted to pinpoint an effective screen-and-treat approach to prevent diabetes in an area where it is prevalent. 

“A screen-and-treat policy will be effective only if a test exists that correctly identifies those at high risk (sensitivity) while also excluding those at low risk (specificity); and an intervention exists that is acceptable to, and also efficacious in, those at high risk,” the researchers wrote.

However, according to their analysis, the diagnostic accuracy of prediabetes tests is low. Fasting glucose is specific but not sensitive, and HbA1c is neither specific nor sensitive, researchers reported. Consequently, the finding suggests large numbers of patients will be unnecessarily treated or falsely reassured and not offered intervention. 

Interventions do have some efficacy in preventing or delaying type 2 diabetes onset, according to the study. Lifestyle interventions that lasted 3 to 6 years showed a 37% drop in relative risk of type 2 diabetes, although the effect dropped to 20% in follow-up studies. Metformin reduced relative risk 26% while patients were on the drug.

A linked editorial by Norman Waugh, a professor at Warwick Medical School, agreed with the need for balance between a screen-and-treat medical model and population-wide public health approaches. However, adherence to lifestyle advice remains poor, he continued.

“Preventing or delaying type 2 diabetes requires effective measures to motivate the general population to protect their own health,” he concluded.—Jolynn Tumolo