Prediabetes is a wide label, and your test, age and history decide what it means

Key takeaways

• In a study of 3,412 adults averaging almost 76, people flagged by A1C were more likely to die (19%) or return to normal (13%) than to develop diabetes (9%) over about five years¹.
• More than 2 in 5 U.S. adults qualify for prediabetes by CDC estimates, yet in 2017 to 2020 only 17.4% of people with it said a health professional had told them²³.
• In the Diabetes Prevention Program, the lifestyle group still had 24% less diabetes after 21 years, though major heart and stroke events didn’t fall⁹¹¹.
• Medicare covers a year-long prevention program with no cost-sharing in Original Medicare, but from 2018 to early 2024 only 9,015 of an estimated 16 million eligible older adults enrolled¹³¹⁵.
• The American Diabetes Association suggests considering metformin mainly for high-risk groups, such as adults 25 to 59 with a BMI of 35 or more; the drug isn’t FDA-approved for this use⁵⁸.

Between 2011 and 2013, researchers tested the blood sugar of 3,412 older adults in the long-running Atherosclerosis Risk in Communities (ARIC) study. None had diabetes, and their average age was 75.6¹.

By at least one standard definition, 73% of them had prediabetes, meaning blood sugar above normal but below the diabetes range¹.

About five years later, the team looked again. Among people flagged by an A1C test, 9% had developed diabetes. More of them, 13%, had drifted back to normal, and 19% had died¹. Among those flagged by a fasting glucose test, 44% were back in the normal range¹.

The authors concluded that in older age prediabetes “may not be a strong diagnostic entity”¹.

That’s one side of a real debate. The other side has strong evidence too: in younger, higher-risk adults, a structured lifestyle program still showed a benefit two decades later⁹. Which side fits you depends mostly on which test flagged you, how old you are and your health history.

More than 2 in 5 adults qualify: where the line sits explains a lot

The CDC now estimates that 42.6% of U.S. adults have prediabetes. Nearly 1 in 5 adolescents ages 12 to 18 and 1 in 4 young adults ages 19 to 34 have it too².

Few know it. In CDC survey data from 2017 to 2020, only 17.4% of adults with prediabetes said a health professional had told them, though that was up from 6.5% in 2005 to 2008³.

Part of the reason the numbers run so high is where the line is drawn, and groups draw it differently:

• American diabetes association (ADA): fasting glucose 100 to 125 mg/dL, A1C 5.7% to 6.4%, or a two-hour glucose tolerance result of 140 to 199⁵.
• World health organization (WHO): a high-risk fasting range of 110 to 125⁴.
• International expert committee (2009): a high-risk A1C range of 6.0% to 6.4%⁴.
• Medicare’s prevention program: a fasting range of 110 to 125 to qualify, along with the ADA’s A1C and two-hour ranges¹³.

These lines moved over time. The ADA lowered its fasting cutoff from 110 to 100 in 2003, and by 2011 it started its A1C range at 5.7%, below the expert committee’s 6.0%⁴.

The ARIC study shows how much that matters. By the ADA’s A1C range, 44% of the older adults had prediabetes; by the expert committee’s range, 15% did. By the ADA’s fasting range, 59% did; by WHO’s, 23%¹. Same blood, very different counts.

The case against the label, and the case for it

In a 2014 BMJ analysis, John Yudkin of University College London and Victor Montori of the Mayo Clinic argued that the label had been stretched too far⁷. Widening the definitions raised prevalence two- to threefold, they wrote, and would label more than half of adults in China as having prediabetes⁷.

Their other points:

• Fasting glucose and A1C predict diabetes less well than the older two-hour glucose test⁷.
• No studies had tested lifestyle or drug treatment in the newly added groups⁷.
• The label can carry costs: worry about self-image, insurance and jobs, health care bills and drug side effects⁷.

A chapter in the federal reference book Diabetes in America adds that diabetes risk rises smoothly, starting at fasting levels as low as about 80, so any cutoff is somewhat arbitrary. It also warns that “prediabetes” can wrongly suggest diabetes is inevitable⁴.

The case for the label is also real. The U.S. Preventive Services Task Force found that, across 23 trials, lifestyle programs lowered progression to diabetes, with a pooled risk ratio of 0.78, or about 22% lower risk⁸. Screening trials found no meaningful rise in anxiety or depression, apart from possible short-term anxiety in people newly diagnosed with diabetes. The Task Force judged the harms of screening and treatment to be small⁸.

There are long-term hints, too. In China’s Da Qing study, 45.7% of people in the lifestyle groups had died after 30 years, versus 56.3% of controls⁸. By our math, that’s about 11 fewer deaths per 100 people. The Task Force cautions that the groups differed at the start in ways that may favor the lifestyle arms⁸.

The fair reading: prediabetes isn’t a disease, and it isn’t meaningless. It’s a wide net that catches people at very different levels of risk.

Who tends to progress, and who doesn’t

The Task Force notes that estimates of progression “vary widely,” partly because prediabetes is defined in different ways⁸. A few patterns stand out.

The two-hour glucose test predicts diabetes better than fasting glucose or A1C⁴⁷. In studies summarized in Diabetes in America, an abnormal two-hour result raised diabetes risk about 6-fold, an abnormal fasting result about 5-fold, and both together about 12-fold⁴. Yet up to 39% of people with an abnormal two-hour test were normal when retested two to six weeks later⁴.

Two abnormal tests also mean more than one. In the ARIC older adults with both a high A1C and a high fasting glucose, about 26.5 people per 1,000 developed diabetes each year, roughly three times the rate in people with normal results¹. By our math, that’s about 2.7 people per 100 a year.

What my prediabetes result means

This tool is our own summary of the sources. It describes groups, not your personal fate.

Your pattern	What studies found	What the evidence supports	Your next step
Age 70 or older, one borderline test	Over about 5 years, 8% to 9% got diabetes, while 13% (A1C) to 44% (fasting) returned to normal1	The study authors suggest heart health and overall survival may deserve more focus1	Ask about blood pressure, cholesterol and activity; recheck yearly5
Both A1C and fasting glucose high	About 2.7 new cases per 100 people a year in older adults, three times normal1	Lifestyle programs lower progression8	Ask about a CDC-recognized program12
Two-hour test 140 to 199	The strongest predictor, but often normal on retest4	Because results often change, a repeat test can clarify4	Ask whether to repeat the test
Fasting 110 to 125 or A1C 6.0% or higher	Ranges WHO and the expert committee also call high risk4	ADA lists these among groups to consider metformin5	Discuss a program, and whether metformin fits
Under 60 with a BMI of 35 or more	Later analyses found metformin’s benefit mainly in people under 60 or with a BMI of 35 or more8	Lifestyle first; metformin is an option5	Talk through both with your clinician
Past gestational diabetes	A higher-risk group in every guideline we checked58	ADA advises testing every 1 to 3 years for life5	Keep up testing; ask about a program

What works: a year-long program with a 21-year record

The proven option is a structured lifestyle program, not a supplement or a cleanse. The CDC-recognized National Diabetes Prevention Program lasts a year and follows an approved curriculum led by a trained lifestyle coach. It teaches healthier eating, more activity and coping skills, working toward at least 150 minutes of activity a week¹². More than 900,000 adults had taken part as of April 2026².

The ADA’s 2026 Standards set the weight goal at 5% to 7% for people with overweight or obesity. They also say certified programs delivered by smartphone, web app or telehealth should be considered, and they advise prescribing a proven eating pattern, naming Mediterranean and low-carbohydrate eating as examples⁵.

The program’s goals come from the Diabetes Prevention Program trial, which cut new diabetes cases by 58% in about three years (our article on realistic goals tells that story)⁹. The follow-up is the bigger news. After 21 years, published in 2025, diabetes rates were 24% lower in the lifestyle group and 17% lower with metformin, compared with placebo⁹. The lifestyle group’s median time without diabetes stretched by 3.5 years⁹.

Volunteers started at an average age of 51 in 1996, and 45% came from racial and ethnic minority groups. The benefits held across groups⁹.

The limits are real. Over a median of 21 years, neither lifestyle nor metformin reduced major cardiovascular events such as heart attacks and strokes¹¹. The researchers point to heavy use of cholesterol, blood pressure and diabetes drugs outside the study, which likely made any benefit harder to detect¹¹.

Approach	What the evidence shows	Rating
CDC-recognized lifestyle program	Delays type 2 diabetes in high-risk adults; benefit lasts 21 years89	Strong evidence
Metformin	Lowers progression about 27% across three trials; not FDA-approved for this use8	Strong evidence for delaying diabetes
Lifestyle program to prevent heart disease or death	No drop in heart events in the DPP; Da Qing favored lifestyle but had baseline imbalances811	Promising but early
A borderline result in your late 70s means diabetes is coming	Most people didn’t progress over five years1	Evidence says no, or unsafe

Supplements marketed for blood sugar get their own article later in this series.

Medicare pays for the program, but almost no one uses it

Medicare covers its own version, the Medicare Diabetes Prevention Program¹³. You qualify if you have Part B or a Medicare Advantage plan, no diabetes diagnosis other than past gestational diabetes, no end-stage kidney disease, and both of these¹³:

• a BMI of 25 or higher, or 23 or higher if you identify as Asian, and
• within the past 12 months, an A1C of 5.7% to 6.4%, a fasting glucose of 110 to 125, or a two-hour result of 140 to 199.

No referral is needed, and Original Medicare charges no copay; Advantage plans may differ¹³. The program has 16 weekly sessions over about six months, then six monthly ones¹³.

Uptake has been tiny. An evaluation for Medicare found that an estimated 16 million Americans 65 and older are eligible, yet suppliers enrolled 9,015 people from April 2018 through March 2024¹⁵. By our math, that’s about 6 in every 10,000 eligible people. Only 414 suppliers had joined by April 2024¹⁵.

Those who took part did fairly well. They lost 4.9% of their weight on average, and 53% reached the 5% goal¹⁵.

Two 2026 changes may help. A law signed February 3, 2026, lifted the old once-per-lifetime limit, so people who finished the program can enroll again once their year of services ends. CMS lists the change as running from 2026 through 2029⁶¹³.

And from January 1, 2026, through December 31, 2029, Medicare covers fully online versions that you complete on your own schedule. You can’t mix online with in-person or live remote sessions¹³.

Metformin is an option for some groups, not for everyone

Metformin, a diabetes pill, also delays diabetes in people with prediabetes. Across three trials, it lowered progression by about 27%⁸. But it isn’t FDA-approved for this use, and it causes more stomach and bowel side effects. A rare but serious reaction called lactic acidosis occurs mainly in people with significant kidney problems⁸.

The ADA’s 2026 Standards suggest considering it for high-risk adults, especially those 25 to 59 with a BMI of 35 or more, a fasting glucose of 110 or higher, an A1C of 6.0% or higher, or a history of gestational diabetes⁵. Long-term users should have vitamin B12 checked from time to time⁵.

In the DPP, lifestyle beat metformin, 24% versus 17% at 21 years, and metformin pushed back the median start of diabetes by about 2.5 years⁹. Whether it fits you is a decision to make with your clinician.

The Task Force and the ADA draw the screening line differently

The Task Force’s 2021 recommendation, still the one posted on its site, gives a “B” grade to screening adults 35 to 70 who have overweight or obesity⁸. It suggests earlier screening for people with a family history of diabetes, past gestational diabetes or polycystic ovary syndrome, and for American Indian, Alaska Native, Asian American, Black, Hispanic or Latino, and Native Hawaiian or Pacific Islander adults. For Asian Americans, it says a BMI cutoff of 23 may fit better⁸.

The ADA casts a wider net. It advises testing adults of any age who have overweight or obesity plus a risk factor, and testing everyone else starting at 35⁵. Both groups suggest repeating normal tests about every three years⁵⁸. Once you have prediabetes, the ADA advises checking at least yearly⁵.

A label you can use on your own terms

Many natural-health readers distrust labels that seem to turn ordinary people into patients. That instinct has support here: in older adults especially, a single borderline number often goes nowhere¹.

The best-proven response to prediabetes also fits natural-health values. It’s food, movement, coping skills and a trained coach, with modest weight loss as the goal rather than a crash diet⁵¹². You can take the useful part of the label, an early nudge, and leave the fear.

Apply the same skepticism to anyone selling a quick fix for blood sugar, whether it comes from a drug company or a supplement brand.

When to get help:

• Get tested soon if you have symptoms such as heavy thirst and frequent urination, rather than waiting for a screening date¹⁰.
• Test 4 to 12 weeks after giving birth if you had gestational diabetes, the ADA advises⁵.
• Plan changes with your prescriber if you already take insulin or a sulfonylurea, since those drugs can push blood sugar too low⁵.
• Talk with a clinician before chasing a weight goal if dieting has ever pulled you toward disordered eating. The National Alliance for Eating Disorders runs a weekday helpline staffed by licensed therapists at 1-866-662-1235; it offers support and referrals, not crisis care¹⁴.

Questions readers ask

The bottom line

Prediabetes is a wide label. For many older adults with one borderline test, it predicts little. For people with two abnormal tests, a high two-hour result, past gestational diabetes or other strong risk factors, it’s a real warning with a proven response.

That response is a year-long lifestyle program, now available online and through Medicare at no cost in Original Medicare. Metformin is a reasonable option for some higher-risk groups, chosen with your clinician.

Keep exploring: blood glucose levels and heart screening tests.

Related reading

• How your body guards the roughly 4 grams of glucose in your bloodstream
• Modest goals cut diabetes risk 58% in a landmark trial, and yours can be just as small
• Your family tree and free risk calculators can show you where to start
• Eight healthy eating patterns faced a 30-year test and mostly agreed
• A 22% risk cut can mean helping 2 or 3 people in 1,000

Sources

1. Rooney MR, Rawlings AM, Pankow JS, et al. “Risk of Progression to Diabetes Among Older Adults With Prediabetes.” JAMA Internal Medicine, 2021;181(4):511–519 (full text hosted by the University of Nebraska Medical Center).
2. Centers for Disease Control and Prevention. “Health and Economic Benefits of Diabetes Interventions.” CDC, May 26, 2026. cdc.gov
3. Centers for Disease Control and Prevention. “Prediabetes.” Diabetes Report Card 2021 (archived), reviewed May 17, 2022. archive.cdc.gov
4. Genuth SM, Palmer JP, Nathan DM. “Classification and Diagnosis of Diabetes.” Diabetes in America, 3rd edition, Chapter 1. NIDDK, 2018. niddk.nih.gov
5. Guideline Central. “2026 ADA Diabetes Standards of Medical Care Clinical Guideline Summary” (summary of American Diabetes Association, Standards of Care in Diabetes—2026). Published December 8, 2025; updated September 16, 2026. guidelinecentral.com
6. Centers for Medicare & Medicaid Services. “Removal of the MDPP Once-Per-Lifetime Limit” (webinar slides). CMS Innovation Center, 2026. cms.gov
7. Yudkin JS, Montori VM. “The epidemic of pre-diabetes: the medicine and the politics.” BMJ, 2014;349:g4485. pubmed.ncbi.nlm.nih.gov
8. U.S. Preventive Services Task Force. “Prediabetes and Type 2 Diabetes: Screening.” Final recommendation statement, August 24, 2021. uspreventiveservicestaskforce.org
9. George Washington University Milken Institute School of Public Health. “Long-term Benefits of Lifestyle and Metformin Interventions in Reducing Type 2 Diabetes over 21 Years in the US Diabetes Prevention Program Study” (on Diabetes Prevention Program Research Group, Lancet Diabetes & Endocrinology, April 2025). April 29, 2025. publichealth.gwu.edu
10. National Institute of Diabetes and Digestive and Kidney Diseases. “Diabetes Tests & Diagnosis.” NIH, reviewed July 2022. niddk.nih.gov
11. American College of Cardiology. “Effects of Metformin and Lifestyle Interventions on CV Events From the Diabetes Prevention Program and Its Outcome Study” (summary of Goldberg RB, et al., Circulation, 2022;145:1632–1641). July 11, 2022. acc.org
12. Centers for Disease Control and Prevention. “What Is the National DPP?” CDC, May 15, 2024. cdc.gov
13. Centers for Medicare & Medicaid Services. “Medicare Diabetes Prevention Program Expanded Model.” MLN booklet MLN34893002, February 2026. cms.gov
14. National Alliance for Eating Disorders. “What Is an Eating Disorder Helpline?” April 14, 2023, accessed October 23, 2026. allianceforeatingdisorders.com
15. Centers for Medicare & Medicaid Services (prepared by RTI International). “Findings at a Glance: Medicare Diabetes Prevention Program (MDPP) Expanded Model, Final Evaluation.” CMS, 2025. cms.gov