Prediabetes Affects More than 97 Million Americans but 77 Million of Them Are Not Aware
The mildly elevated glycemia of prediabetes is a pathological condition with serious risks for those 77 million, says endocrinologist Samuel Dagogo-Jack, MD, DSc.
We need to raise awareness that prediabetes is not a benign condition. I was truly gratified by the large attendance at today's early morning session, which gives hope that physicians take this condition seriously.
Prediabetes affects an estimated 97.6 million adults in the US and 860 million people worldwide. But population awareness of prediabetes remains remarkably low, according to Samuel Dagogo-Jack, MD, DSc. Although awareness of the pathological condition has improved somewhat, from just 4%-7.7% in 2005-2006 to approximately 20% in 2020-2022, even the most current data suggest that 80% of the population living with prediabetes does not know it, leaving them vulnerable to progression to full blown type 2 diabetes.1
Dagogo-Jack, AC Mullins endowed professor of medicine and director of the division of endocrinology, diabetes, and metabolism at the University of Tennessee Health Science Center, in Memphis, TN, spoke to an auditorium filled with internal medicine physicians at the 2025 ACP Internal Medicine Meeting, April 3-5, in New Orleans. His presentation, Prediabetes for internal medicine physicians: approach to screening, diagnosis, and management,1 began at 7 a.m. He expressed both surprise at and gratitude for the nearly standing room only attendance. Patient Care© caught up with him for a short conversation after a lengthy question/answer period that eventually moved to the convention center corridors. The following is a transcript of the conversation, edited for clarity and length.
Patient Care: In your presentation, you mentioned that only about 20% of people with prediabetes are aware of their condition. What’s the most efficient screening approach for primary care physicians?
Samuel Dagogo-Jack, MD, MSc: There are 3 recommended tests for diagnosing prediabetes: fasting blood glucose, the oral glucose tolerance test (OGTT), and hemoglobin A1c (HbA1c). Both fasting glucose and OGTT require patients to fast for 8–12 hours, which can be impractical in a busy primary care setting. As a result, many clinicians prefer the HbA1c test. In general, a normal HbA1c is below 5.7%. A result between 5.7% and 6.4% indicates prediabetes.
PC: You mentioned that the concordance among these tests is quite low—just 4.1%. What should clinicians keep in mind when interpreting A1c results, especially across different ethnic groups?
Dagogo-Jack: That’s an important point. HbA1c reflects the average blood glucose level over the past three months. But this relationship can vary by ethnicity and other conditions. For instance, people with anemia or blood disorders like thalassemia or sickle cell disease may have unreliable HbA1c results. The same is true for patients on dialysis or pregnant women.
Moreover, studies have consistently shown that African Americans may have higher A1c levels than white patients, even at the same blood glucose levels. So, relying solely on HbA1c could lead to overdiagnosis in some groups. That’s why it's recommended to confirm borderline HbA1c results with actual blood glucose measurements. If those are normal, it may be more appropriate to hold off on labeling someone with prediabetes.
That said, HbA1c remains the gold standard for monitoring glucose control in patients who have already been diagnosed with diabetes. Regardless of background, if someone’s HbA1c drops from 9% to 7%, that’s a clear sign of improved control.
PC: You also shared findings from your PROP-ABC1 study about reversing prediabetes. What are the key takeaways for primary care clinicians?
Dagogo-Jack: his study was unique in that it enrolled individuals at high risk—people whose parents had type 2 diabetes—but who had normal blood sugar at baseline. We followed them closely every 3 months for 5 years. If someone’s glucose levels shifted into the prediabetes range, they were immediately offered intensive lifestyle intervention—no medication, just regular counseling on diet and exercise with face-to-face meetings with a clinician each month for the first 6 months and quarterly thereafter.
The results were striking: nearly half of those who received early intervention returned to normal glucose levels. The message here is that detecting prediabetes early and acting on it quickly—before it progresses to diabetes—can truly reverse the condition.
PC: Was that the same study that included a phase with only passive notification?
Dagogo-Jack: Yes. In the earlier phase, patients were simply notified of their elevated glucose levels. In the second phase, we actively provided lifestyle intervention, which had a much greater impact.
PC: You also pointed out that very few clinicians take action when a patient's glucose levels indicate prediabetes—less than 1%. Why is that, and what can be done?
Dagogo-Jack: Unfortunately, yes. Many physicians still view blood sugar in a binary way—either normal or diabetic. We need to change that mindset and recognize prediabetes as a legitimate pathological condition with real risks and is already the substrate for both micro- and macrovascular complications. It’s not a minor blip; it’s a warning sign.
One solution is to build prompts into the electronic health record that alert physicians when a patient has prediabetes and reminds them to address it. These don’t need to prompt a prescription; they could encourage lifestyle counseling, which is often enough to prevent progression. Most people with prediabetes don’t need medication—they need guidance on healthy eating and physical activity. The benefits are substantial.
PC: Do you believe American medicine is too quick to prescribe metformin for patients with mildly elevated glucose?
Dagogo-Jack: That does happen, partly because primary care clinicians are pressed for time. But counseling is powerful, especially when it comes from the physician. I make a point to counsel my patients personally—before referring them to a dietitian. As endocrinologists, we should be trained and prepared to "prescribe" diet and exercise, not just medications. Yes, it takes more time, but it also empowers the patient and reinforces that their actions—not just the prescription—matter most.
PC: On a final note, what do you see as the biggest challenges facing internal medicine in the next 3 to 5 years?
Dagogo-Jack: One major challenge is the talent pipeline: attracting and retaining young people in medicine. The long training, coupled with issues like burnout, reimbursement concerns, and a shift toward employment-based practice models, is discouraging. Many decisions about your workload or pay are made by people who aren’t even physicians. That erodes the sense of autonomy and purpose that brought many of us to medicine in the first place. We're losing brilliant minds to tech and business. We need to restore the appeal of medicine so that it continues to attract the best and brightest.
