USPSTF diabetes screening misses most people

A study looked at the sensitivity/specificity of the current USPSTF guidelines for diabetes screening in a community setting, finding over half the cases are missed (see dm a1c USPSTF misses half PLoS2016, or http://journals.plos.org/plosmedicine/article/asset?id=10.1371%2Fjournal.pmed.1002074.PDF​ ). The USPSTF in 2015 recommended diabetes screening for those aged 40-70 and who are overweight/obese. details:

--retrospective analysis of electronic health record data of 50,515 adult primary care patients seen between 2008-2010 in 6 health centers in the Midwest and Southwest, followed for up to 3 years (median 1.9). [this screening was prior to the 2015 USPSTF guidelines]

​--18,846 (37%) were >40 yo; 33,537 (66%) were overweight or obese; 39,061 (77%) were racial/ethnic minorities (35% Black, 334% Hispanic, 9% other)

--they excluded patients with dysglycemia (glucose intolerance or diabetes) at baseline

--they then compared the actual findings of dysglycemia (by the usual fasting or post-prandial sugar/A1c) criteria with who would have not been screened if adhering to the later-published 2015 USPSTF guidelines

--results:

    --29,946 (59%) had a glycemic test within 3 y of follow-up

    --8,478 of them developed dysglycemia (78% by using the A1C criteria)

    --12,679 (25%) of the 50,515 patients overall would have been eligible for screening per the 2015 USPSTF guidelines

        --overall sensitivity of the guidelines was 45.0% (43.9-46.1%)

        --overall specificity was 71.9% (71.3-72.5%)

        --PPV was 38.8% and NPV was 76.8%

        --subgroup analysis:

            --compared to normal weight: overweight people had 31% more dysglycemia; obese 145% increase

-- PCOS 124% increase

--dramatic increases in dysglycemia in those with increasing number of diabetes risk factors (the Am Diabetes Assn risk factors as noted below)

   --on multivariate analysis, significant associations with the development of dysglycemia: age >40, overweight/obese, nonwhite race/ethnicity, hypertension, PCOS, history of gestational diabetes, family history of diabetes

   --dysglycemia cases in racial/ethnic minorities were significantly less likely to be eligible for USPSTF-guideline based screening, though they had higher odds for developing dysglycemia (OR for Black patients 1.24; Hispanic 1.46). the sensitivity for different racial/ethnic groups was:

        --white: 54.5%

        --Black: 50.3%

        ​--Hispanic/Latino: 37.7%

        --and the lower sensitivity in racial/ethnic minorities reflects the greater proportion of patients who developed dysglycemia at a normal weight and under 40 yo (eg, 20% of Hispanic/Latino patients of normal weight developed dysglycemia, as well as 31% of those <40yo)

commentary:

--diabetes is really common: from the USPSTF document: “approximately 86 million Americans aged 20 years or older have IFG or IGT. Approximately 15% to 30% of these persons will develop type 2 diabetes within 5 years if they do not implement lifestyle changes to improve their health”

--many studies over the last several decades in several different countries show that intensive lifestyle interventions can prevent or at least delay the development of diabetes, with reasonable argument that this would significantly decreased the associated micro- and macrovascular morbidity. This strongly supports the likely utility of screening/potential for earlier intervention.

--it should be noted that the Am Diabetes Assn has much more expansive guidelines (see http://care.diabetesjournals.org/content/suppl/2015/12/21/39.Supplement_1.DC2/2016-Standards-of-Care.pdf , p16) for testing asymptomatic adults:

    --all overweight (BMI >25, or >23 in Asian-Americans) with at least one additional risk factor: physical inactivity, first-degree relative with diabetes, members of high-risk ethnic group (African American, Latino, Native American, Pacific Islander), women who had baby >9 # or had gestational diabetes, hypertension, HDL <35 or triglyceride >250, other clinical condition associated with diabetes (eg acanthosis nigricans), history of CVD

    --in absence of above, everyone at age 45

--the NICE guidelines in the UK focus on those at high diabetes risk, independent of obesity (see https://www.diabetes.org.uk/Documents/About%20Us/What%20we%20say/Position%20Statement%20-%20Early%20identification%20of%20people%20with%20Type%202%20diabetes%20(Nov%202015).pdf​ )

--there are clear limitations of this study. this was not a prospective study of all-comers to assess the prevalence of dysglycemia, along with individual risk factors. and even in the PLoS analysis, they do not disaggregate the issues of age<40 and normal weight (ie, it is not entirely clear if normal weight people who also are <40 yo have a significant incidence of dysglycemia). [On my brief search, I was quite surprised at how little epidemiological data was available on the prevalence of glucose intolerance in the US population, including different ethnicities/other subgroups.]

--my experience absolutely reflects the results of the PLoS study: we find many people who have either glucose intolerance or diabetes who would not qualify under the current USPSTF guidelines (I have been using the Am Diabetic Assn guidelines, though I should add that in our health center, a very large % of our patients under age 40 do qualify for testing by these guidelines). however, though this study is not definitive, it really raises the ante: it seems that a fair number of patients under 40yo or with normal weight have dysglycemia. And it seems to me that the benefits (early reinforcement of intensive lifestyle changes) far outweigh the risks….​