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Screen all adults 45 or over for abnormal glucose, says US panel

BMJ 2014; 349 doi: https://doi.org/10.1136/bmj.g6146 (Published 09 October 2014) Cite this as: BMJ 2014;349:g6146
  1. Michael McCarthy
  1. 1Seattle

All adults aged 45 or older should be screened for abnormal blood sugar concentrations, as well as adults under 45 who have risk factors for impaired fasting glucose, impaired glucose tolerance, or diabetes, say draft recommendations released 6 October by the US Preventive Services Task Force.1 The recommendations are open for public comment until 3 November.

Type 2 diabetes mellitus typically develops slowly, progressing from normal blood glucose to impaired fasting glucose or impaired glucose tolerance and to diabetes, a process that can take a decade or longer. Both impaired glucose tolerance and impaired fasting glucose are risk factors for diabetes, the task force noted.

If adopted, the new recommendation would update the task force’s 2008 guideline, which recommended screening for diabetes in adults with hypertension (sustained blood pressure >135/80 mm Hg). The task force’s assessment at that time found insufficient evidence to assess the balance of benefits and harms of screening adults without hypertension.

The task force is an independent panel commissioned by the US government to make recommendations on preventive care for patients who do not have signs or symptoms of the condition under review. Its recommendations are based on evidence of benefits and harms. It does not consider the costs of providing a service in its assessments.

Figures from the US Centers for Disease Control and Prevention show that 37% of Americans aged 20 years or older, about 86 million people, have impaired fasting glucose or impaired glucose tolerance and that 12%, or about 29 million, have diabetes, which has not been diagnosed in about eight million people.2 The increasing prevalence of abnormal glucose metabolism in the US population, which has risen from 5% in 1995 to 9% in 2012, prompted the re-examination of the benefits and harms of screening, the task force said.

Among those who are younger than 45 who should be screened because they at higher risk are those who are overweight or obese, those with a first degree relative with diabetes, and women with a history of gestational diabetes or polycystic ovarian syndrome, the task force concluded. Also at higher risk are members of certain racial and ethnic groups, the task force said, including African Americans, American Indians and Alaska Natives, Asian Americans, Hispanics and other Latinos, and Native Hawaiians and other Pacific Islanders. The age adjusted prevalence of diabetes is 13.9% among Mexican Americans in the United States and 15.9% among American Indians and Alaska Natives, for example, but 7.6% among non-Hispanic whites.

The task force did not endorse any particular risk assessment tool.

Screening can involve measurement of hemoglobin A1c or fasting plasma glucose or an oral glucose tolerance test, the task force said, though because hemoglobin A1c measurement did not require a fasting state it was the more convenient test, it added. Random blood glucose measurements should not be used for screening, the task force said.

Although noting that the evidence was limited, the task force concluded that adults at low risk should be screened every three years and those at high risk or those who have near abnormal test values should be screened annually. “Clinical trials and additional modeling studies are needed to better elucidate the optimal frequency of screening and the age at which to start screening,” the task force said.

Although the task force did not find adequate “direct evidence” that measuring blood glucose alone led to improvement in mortality and cardiovascular morbidity, it did find adequate evidence that screening adults at increased risk and treating those with impaired fasting glucose or impaired glucose tolerance with intensive lifestyle interventions had a moderate benefit in decreasing the risk of progression to diabetes and in lowering the incidence of cardiovascular and all cause mortality. These lifestyle modifications included improved nutrition, healthy eating behaviors, and increased physical activity.

As for harm, the task force found that although measuring blood glucose was associated with some short term anxiety it was not associated with long term psychological harm and that the harms of the lifestyle interventions were “small to none.”

The harms of drug treatment to prevent diabetes were “small to moderate,” depending on the drug and dosage used, the task force said. It concluded that, overall, screening would have a “moderate net benefit” in adults at risk of diabetes.

Victor M Montori of the Mayo Clinic, Rochester, Minnesota, who with John S Yudkin of University College London coauthored a recent article in The BMJ that voiced concerns that the overdiagnosis of “pre-diabetes” was unnecessarily turning healthy people into patients, said in an email that by making abnormal glucose concentrations a clinical problem the recommendations would make it more likely that abnormal levels would be dealt with through clinical interventions instead of a broader public health approach.

“Given that the percentage of people that qualify is so high, large amounts of resources will need to be dedicated to this program, including the use of medications of unclear value in this population,” Montori said. The approach recommended by the task force completely ignored the major role of social and environmental factors in the development of abnormal blood glucose concentrations, he said, “facilitating the ongoing growth of the numbers of those considered at risk.”

Notes

Cite this as: BMJ 2014;349:g6146

Footnotes

  • thebmj.com Analysis: The epidemic of pre-diabetes: the medicine and the politics (BMJ 2014;349:g4485, doi:10.1136/bmj.g4485).

References

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