Two experts from the Beth Israel Deaconess Medical Center in Boston debated the benefits and harms of screening patients for type 2 diabetes at the institution’s Department of Medicine Grand Rounds conference.
“The prevalence of diabetes in the United States has increased over recent decades and has paralleled the increase in obesity rates. At present, 12% of U.S. adults have diabetes mellitus and another 37% have impaired fasting glucose (IFG) or impaired glucose tolerance (IGT),” Gerald W. Smetana, MD, also from the Beth Israel Deaconess Medical Center and Harvard Medical School, wrote in a “Beyond the Guidelines” paper based on the discussion.
The U.S. Preventive Services Task Force (USPSTF) recommends that overweight or obese patients aged 40 to 70 years without symptoms of diabetes undergo blood glucose screening every 3 years, according to Smetana.
Martin J. Abrahamson, MB, ChB, in favor of screening, and David M. Rind, MD, against screening, debated their viewpoints at the conference.
According to Abrahamson, 25% of patients with diabetes have never been diagnosed. Diabetes often goes undetected due to a prolonged asymptomatic stage, he said.
“People with diabetes have a high prevalence of depression, absenteeism from work and decreased productivity, all of which add to the morbidity of the disease,” he said. “We cannot wait for symptoms of diabetes to develop before diagnosing this condition—we need to intervene beforehand.”
Abrahamson noted that the screening tests are easy to administer, provide reliable results and do not have any adverse consequences.
In opposition, Rind pointed out that the USPSTF’s recommendation is to screen for abnormal blood glucose “as a part of cardiovascular (CV) risk assessment” which does not suggest that the purpose of the screening is to identify and prevent diabetes. Rather, he claims that improving the CV risk estimate is the focal point of the guideline.
Rind defined “diabetes” as a surrogate outcome for patients who meet laboratory criteria for type 2 diabetes but are asymptomatic.
“Screening for ‘diabetes’ is unlikely to be helpful in patients at low risk for diabetes or who are at either low or high CV risk, since finding ‘diabetes’ is unlikely to change management or improve outcomes,” Rind argued.
However, Abrahamson argued that diabetes is not a surrogate outcome because interventions during this phase reduce the risk for complications over time.
According to Abrahamson, progression to diabetes can be reduced by identifying prediabetes in asymptomatic overweight or obese patients and enrolling those patients in a lifestyle modification program to increase exercise and weight loss. Lifestyle interventions can improve outcomes and reduce the risk for progression to type 2 diabetes.
“There is evidence that lifestyle intervention reduces the risk for type 2 diabetes in individuals with IFG and IGT (prediabetes) by 58%,” he said. However, he noted that a lifestyle intervention may not influence the risk of mortality or CV disease during a brief period though possible benefits may be seen after many years.
Abrahamson added that patients with prediabetes may also be treated with metformin which reduces the risk for type 2 diabetes by 31%.
Rind argues that these lifestyle interventions are general recommendations for any patient who is overweight or obese. He said, metformin can be administered to patients with prediabetes to prevent progression to diabetes; however, lifestyle changes are more effective and “metformin has not been shown to reduce the risk that patients with prediabetes will develop micro- or macro-vascular complications.”
Rind cited the results from a meta-analysis of 10 randomized trials which discovered that “while interventions reduce progression to ‘diabetes,’ they had no effect on all-cause mortality or CV mortality.” He added, “Interventions that reduce ‘diabetes’ do not actually appear to improve patient-important outcomes.”
Abrahamson stressed the importance of screening for type 2 diabetes because of its underlying morbidity as well as the preventive measures such as lifestyle interventions that can be enforced to reduce and prevent the risk of progression of the disease. Rind argued that screening all patients would be ineffective and suggested a more individualized approach — to screen patients who would be more inclined to make lifestyle changes given the results of testing. – by Alaina Tedesco
Disclosure: Rind reports receiving personal fees from UpToDate outside of the submitted work. Abrahamson reports having served on Advisory Boards for Novo Nordisk, Inc.