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Prediabetes is a critical health condition that affects millions of people worldwide, characterized by blood sugar levels between 5.7% and 6.4% A1C, which are higher than normal but not yet high enough to be diagnosed as type 2 diabetes. Approximately 70% of people with prediabetes will go on to be diagnosed with diabetes mellitus, making early intervention essential. While lifestyle modifications remain the cornerstone of prediabetes management, medications play an important role in specific situations. Understanding when medications are necessary, which options are available, and how they work alongside lifestyle changes can empower individuals to take control of their health and prevent the progression to type 2 diabetes.
Understanding Prediabetes: A Critical Window for Intervention
The main cause of prediabetes is insulin resistance, which happens when cells in your muscles, fat and liver don’t respond as they should to insulin. This hormone is essential for regulating blood glucose levels throughout the body. When insulin resistance develops, the pancreas initially compensates by producing more insulin, but over time, this system becomes overwhelmed, leading to elevated blood sugar levels.
Prediabetes is a component of metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus, and people with prediabetes often have obesity (especially abdominal or visceral obesity), dyslipidemia with high triglycerides and/or low HDL cholesterol, and hypertension. It is also associated with increased risk for cardiovascular disease, making it more than just a precursor to diabetes—it’s a significant health concern in its own right.
Diagnostic Criteria for Prediabetes
Healthcare providers use several blood tests to diagnose prediabetes. Any of the following test results indicate prediabetes: Fasting blood glucose of 100 to 125 mg/dL (called impaired fasting glucose) or Blood glucose of 140 to 199 mg/dL 2 hours after taking 75 grams of glucose (called impaired glucose tolerance). Additionally, the A1C test measures your average blood sugar level for two to three months, with an A1C of 5.7% or less being normal and a prediabetes A1C between 5.7 and 6.4%.
Many people with prediabetes are unaware of their condition. More than 2 in 5 American adults have prediabetes, yet most people are unaware they have it. This is because prediabetes rarely causes symptoms, making routine screening essential for early detection and intervention.
Risk Factors for Developing Prediabetes
Several factors increase the likelihood of developing prediabetes. Major risk factors include overweight or obesity, physical inactivity, family history of diabetes, and a history of gestational diabetes. Other important risk factors include age over 45, having a parent or sibling with type 2 diabetes, and belonging to certain ethnic groups with higher diabetes risk, including African American, Hispanic/Latino, Asian, Pacific Islander, or Native American populations.
The American Diabetes Association (ADA) recommends normal testing repeated every three years and recommends a larger range of people get tested: anyone over the age of 45 regardless of risk; an adult of any age who is obese or overweight and has one or more risk factors. Early screening allows for timely intervention before prediabetes progresses to type 2 diabetes.
When Are Medications Recommended for Prediabetes?
While lifestyle modifications are always the first-line treatment for prediabetes, medications may be considered in specific circumstances. The American Diabetes Association draws its recommendations from the subgroups in the DPP in which metformin was as effective as lifestyle intervention, sharing that metformin should be considered in those with prediabetes, especially those with a BMI ≥35 kg/m2, younger individuals, and women with a history of gestational diabetes.
Specific Criteria for Medication Consideration
The American Diabetes Association recommends that prescription medications may be considered for those with prediabetes, including those in a specific subgroup who are more likely to have a greater benefit from medications and are at a higher risk of progressing to diabetes, including those with a BMI greater than 35, age less than 60, women with a history of gestational diabetes, a fasting plasma glucose greater than 110 or an A1c greater than 6%.
This may also be considered in patients for whom lifestyle therapy has failed, or is not sustainable, who are at high-risk for developing type 2 diabetes, or who prefer to take a medication. Medication is prescribed to prediabetes patients who have one or more of the following risk factors: failure to adjust diet and lifestyle over a long period, low HDL cholesterol, high triglycerides, or a family history of diabetes or obesity.
High-Risk Populations
Certain populations benefit more from medication intervention. Although lifestyle intervention was beneficial in all groups, metformin had a selectively greater effect in those who were more obese, had a higher fasting glucose, had a history of gestational diabetes, or were younger. This targeted approach ensures that those most likely to progress to type 2 diabetes receive appropriate pharmacological support alongside lifestyle modifications.
If you’re at high risk for developing diabetes, they may consider metformin earlier, even before extensive lifestyle modification attempts. This proactive approach can be particularly important for individuals with multiple risk factors or those who have already demonstrated difficulty maintaining lifestyle changes.
Metformin: The Primary Medication for Prediabetes
Metformin is currently the only antidiabetic medication for prediabetes recommended by the American Diabetes Association (ADA). This medication has been extensively studied and has demonstrated both safety and effectiveness in preventing or delaying the progression to type 2 diabetes.
How Metformin Works
Metformin, classified as a biguanide drug, effectively lowers blood glucose levels by decreasing glucose production in the liver, diminishing intestinal absorption, and enhancing insulin sensitivity. More specifically, it lowers the amount of glucose produced by your liver, lowers the amount of glucose absorbed from the food you eat in your intestines, and helps your body use its natural insulin more effectively.
Recent research has expanded our understanding of metformin’s mechanisms. While the liver is traditionally considered the primary site of metformin’s glucose-lowering action, growing evidence suggests that the gastrointestinal tract also plays a crucial role in its action, with Complex I inhibition and AMPK activation in intestinal cells being crucial in metformin’s mechanism of action.
Evidence from the Diabetes Prevention Program
The landmark Diabetes Prevention Program (DPP) provided crucial evidence for metformin’s effectiveness in prediabetes. The Diabetes Prevention Program randomized clinical trial demonstrated that intensive lifestyle intervention and metformin therapy reduced progression to diabetes by 58 and 31%, respectively, compared to placebo in people at risk of type 2 diabetes.
Compared with placebo, the intensive lifestyle intervention reduced the incidence of type 2 diabetes by 58% (95% CI: 48%-66%), while metformin reduced it by 31% (95% CI: 17%-43%); however, in a direct comparison, the intensive lifestyle intervention was significantly more effective than metformin. This finding underscores the importance of lifestyle changes as the primary intervention, with medication serving as an adjunct or alternative when lifestyle modifications are insufficient.
Long-term effects included an 18% diabetes reduction with metformin compared to placebo over 15 years, a reduction in microvascular complications among those who did not progress to diabetes (without difference among treatment arms), and suggestion by coronary calcium assessment of a possible impact on atherosclerosis in men. These long-term benefits demonstrate that metformin’s effects extend beyond simple glucose control.
Metformin Dosing and Administration
Because taking metformin for prediabetes is an off-label use of the medication, there are no standard doses provided by manufacturers. However, healthcare providers typically follow established protocols. Prescribers start with low doses of metformin to help limit side effects, with an example of a starting dose of metformin being 850 mg once a day — which is then increased to twice a day after a few weeks.
Based on the efficacy and safety evaluation results, findings suggest that a daily dosage of 750 mg of metformin may represent the optimal dose for controlling the progression from pre-diabetes to diabetes. This dosage balances effectiveness with tolerability, though individual needs may vary.
Metformin is available in immediate-release (IR) and extended-release (ER) versions, with Metformin IR typically taken twice daily with meals and Metformin ER usually taken once a day with or without food. The extended-release formulation may offer improved tolerability for some patients, particularly those experiencing gastrointestinal side effects.
Timeline for Metformin Effectiveness
Metformin begins working after only a few doses, with many people seeing significantly lower blood glucose levels within the first week, but it may take a month or two to achieve the full effect. This relatively rapid onset of action allows healthcare providers to assess effectiveness and make dosage adjustments within a reasonable timeframe.
Side Effects and Safety Profile
The medication has been studied for several decades and is generally safe for many people to take, with a very low risk of sudden hypoglycemia (low blood glucose) and requiring minimal monitoring by both you and your prescriber. This favorable safety profile makes metformin an attractive option for long-term use in prediabetes management.
The most common side effects of metformin are gastrointestinal, including nausea, diarrhea, and abdominal discomfort. These effects are typically mild and often resolve as the body adjusts to the medication. Starting with a low dose and gradually increasing it can help minimize these side effects. The extended-release formulation may also reduce gastrointestinal symptoms.
An additional benefit for many patients is that metformin can cause weight loss, which is listed as a side effect, though many people consider weight loss as a benefit, since losing weight often improves diabetes and prediabetes. This weight loss effect can complement lifestyle modifications and contribute to overall metabolic improvement.
Global Acceptance and Licensing
Metformin is currently the only antidiabetic medication recommended for prediabetes by ADA and has been approved for prediabetes in at least 66 countries. In the United Kingdom, slow-release (but not standard-release) metformin is licensed for delaying the onset of type 2 diabetes, specifically in overweight individuals with IGT and/or IFG who are at high cardiovascular risk and who are at high risk of progressing to frank diabetes despite lifestyle change.
Despite this widespread acceptance, currently, there are no medications that are FDA approved for prediabetes in the United States, meaning metformin use for this indication remains off-label. Despite this wealth of data, the uptake of metformin for the prevention of type 2 diabetes has been extremely low, with the age-adjusted prevalence of metformin use among adults with prediabetes being 0.7%.
Other Medications for Prediabetes
While metformin remains the primary medication recommended for prediabetes, other pharmacological options exist and may be considered in specific circumstances.
Acarbose
Metformin and acarbose help prevent the development of prediabetes, and also have a good safety profile. Acarbose works by slowing the digestion of carbohydrates in the small intestine, which helps prevent spikes in blood sugar after meals. The most common medications used for prediabetes are metformin and acarbose, which will help prevent the development of diabetes mellitus, and these two drugs have minimal side effects and work well in prediabetic patients.
Acarbose may be particularly useful for individuals who experience significant postprandial (after-meal) glucose elevations. However, it can cause gastrointestinal side effects such as bloating, gas, and diarrhea, which may limit its tolerability for some patients.
Thiazolidinediones
Evidence also supports thiazolidinediones but there are safety concerns. Thiazolidinediones (TZDs) work by improving insulin sensitivity in muscle and fat tissue. While they can be effective in preventing diabetes progression, concerns about side effects including weight gain, fluid retention, bone fractures, and potential cardiovascular effects have limited their use for prediabetes.
GLP-1 Receptor Agonists and Newer Agents
There are currently no long-term data supporting medications other than metformin specifically for preventing type 2 diabetes, however, newer medications such as GLP-1–based drugs can help with weight loss in people who are overweight or have obesity. These medications work by mimicking the effects of glucagon-like peptide-1 (GLP-1), a hormone that stimulates insulin secretion, suppresses glucagon release, slows gastric emptying, and promotes satiety.
These medications should not be given to patients solely for prediabetes; however, when prescribed for the appropriate indication, they may lead to weight loss that can mitigate the progression of prediabetes to diabetes. This means that while GLP-1 receptor agonists are not specifically approved for prediabetes treatment, they may be prescribed for weight management in individuals who meet criteria for obesity treatment, with the added benefit of reducing diabetes risk.
Lifestyle Modifications: The Foundation of Prediabetes Management
Regardless of whether medication is prescribed, lifestyle modifications remain the cornerstone of prediabetes management. Lifestyle changes, like diet and exercise, are more effective at reversing the condition than medication alone. The first choice for treatment is usually lifestyle changes, and medications should be viewed as complementary rather than replacement therapy.
Weight Loss Goals
The CDC’s national Diabetes Prevention Program (DPP), which includes an ongoing Outcomes Study, has shown that people with prediabetes who lost a modest amount of weight—5 to 7% (10 to 14 pounds for a person weighing 200 pounds, for example)—with the help of a structured lifestyle-change program cut their risk of developing type 2 diabetes by 58%.
Weight loss is a key strategy to reverse prediabetes, but it’s important to know that not everyone needs to lose a massive amount of weight, with often only minor changes in dietary intake and minimal weight loss, together with more physical activity, helping chase diabetes away. A relatively small amount of weight loss ― 5% to 10% of your body weight ― can help lower your blood sugar.
Dietary Recommendations
A healthy diet for prediabetes management should focus on whole, nutrient-dense foods while limiting processed foods, added sugars, and refined carbohydrates. To help prevent diabetes, providers will likely suggest eating healthy foods including whole grains, lean proteins, low-fat dairy, and plenty of vegetables, watching portion sizes and avoiding sweets, fried foods, and excessive amount of fruits.
Many studies suggest that a low-carbohydrate diet can help control insulin resistance, blood glucose levels, and weight issues, with consuming low sodium at levels less than 1500 mg per day, limiting alcohol to zero or one drink per day, and cutting out added sugar being additional important dietary strategies.
Key dietary principles include:
- Choosing complex carbohydrates over simple sugars
- Increasing fiber intake through vegetables, fruits, and whole grains
- Selecting lean protein sources
- Incorporating healthy fats from sources like nuts, seeds, avocados, and olive oil
- Controlling portion sizes
- Limiting processed foods and beverages with added sugars
- Staying hydrated with water rather than sugary drinks
Physical Activity Recommendations
The most effective way to manage prediabetes is by making lifestyle changes, such as losing weight and exercising for at least 30 minutes daily, as these activities can improve insulin resistance, lower elevated blood sugar levels, and help prevent progression to diabetes.
Physical activity helps manage prediabetes through multiple mechanisms:
- Improving insulin sensitivity in muscle tissue
- Helping with weight management
- Lowering blood glucose levels
- Reducing cardiovascular risk factors
- Improving overall metabolic health
Both aerobic exercise (such as walking, jogging, swimming, or cycling) and resistance training (such as weight lifting or bodyweight exercises) are beneficial. A combination of both types of exercise may provide optimal results. The key is finding activities that are enjoyable and sustainable over the long term.
Additional Lifestyle Factors
Beyond diet and exercise, other lifestyle factors play important roles in prediabetes management:
- Sleep: Adequate sleep (7-9 hours per night for most adults) is essential for metabolic health and glucose regulation
- Stress management: Chronic stress can affect blood sugar levels and make it harder to maintain healthy lifestyle habits
- Smoking cessation: Smoking increases insulin resistance and diabetes risk
- Alcohol moderation: Excessive alcohol consumption can affect blood sugar control and contribute to weight gain
Monitoring and Follow-Up Care
Regular monitoring is essential for individuals with prediabetes, whether or not they are taking medication. Once diagnosed with prediabetes patients should be checked for progression to type 2 diabetes every one to two years. This ongoing surveillance allows healthcare providers to assess the effectiveness of interventions and make adjustments as needed.
What to Monitor
Regular follow-up appointments should include:
- Blood glucose testing: A1C tests every 3-6 months, or fasting glucose and/or oral glucose tolerance tests as recommended by your healthcare provider
- Weight and BMI: Regular tracking of weight loss progress
- Blood pressure: Monitoring for hypertension, which often coexists with prediabetes
- Lipid profile: Checking cholesterol and triglyceride levels
- Kidney function: Particularly important for patients taking metformin
- Vitamin B12 levels: Long-term metformin use can affect B12 absorption
Assessing Treatment Effectiveness
Healthcare providers evaluate treatment effectiveness by looking at multiple factors:
- Changes in A1C or fasting glucose levels
- Weight loss progress
- Improvements in other metabolic markers (blood pressure, lipids)
- Patient adherence to lifestyle modifications
- Tolerance of medications (if prescribed)
- Overall quality of life and well-being
If blood glucose levels return to normal range, this represents successful reversal of prediabetes. However, continued monitoring and maintenance of healthy lifestyle habits remain important, as the risk of recurrence exists without ongoing vigilance.
Adjusting Treatment Plans
Treatment plans should be dynamic and adjusted based on individual response. If lifestyle modifications alone are not achieving desired results after 3-6 months, medication may be considered. Conversely, if someone on medication achieves significant weight loss and improved glucose control through lifestyle changes, medication dosage may potentially be reduced under medical supervision.
The Debate: Medication vs. Lifestyle-Only Approaches
The use of medication for prediabetes remains somewhat controversial in the medical community. It can be counterargued that a pharmacological approach over-medicalizes what is essentially a public health problem and exposes relatively healthy people to lifelong medication (and associated potential adverse effects) when they could be participating instead in a healthy lifestyle programme.
Arguments for Medication Use
Several guidelines, including those from the International Diabetes Federation, have recognized that metformin is a cost-effective pharmacological intervention in people at high risk of developing diabetes, supported by data from the DPP and DPPOS suggesting that over 10 years, metformin treatment is cost-saving, decreasing the cumulative costs of medical care.
Additional arguments supporting medication use include:
- Not all individuals can successfully implement or maintain lifestyle changes
- Some people face significant barriers to lifestyle modification (physical limitations, socioeconomic factors, mental health challenges)
- Medication can provide additional protection for high-risk individuals
- Early intervention with medication may prevent or delay complications
- The combination of medication and lifestyle changes may be more effective than either alone for certain individuals
Arguments Against Routine Medication Use
The arguments against the broad use of metformin in people with prediabetes include the substantial number of people with prediabetes either returning to normal glucose regulation or not progressing to diabetes, and if there is not strong correlation between targeting blood glucose solely in prediabetes with a medication and if sometimes people become normoglycemic anyway, why start a medication that may be continued forever.
Other concerns include:
- Potential side effects, even if generally mild
- Cost of medication and monitoring
- Risk of medicalizing a condition that may be reversible with lifestyle changes alone
- Uncertainty about optimal duration of treatment
- Limited long-term data on outcomes beyond glucose control
Finding the Right Balance
In general, it is important to look at the patient with prediabetes holistically—ensuring lifestyle modifications are emphasized, and, as appropriate, considering metformin based on the unique, individualized factors present in a given patient with prediabetes. This personalized approach recognizes that there is no one-size-fits-all solution and that treatment decisions should be made collaboratively between patients and healthcare providers.
Special Populations and Considerations
Women with History of Gestational Diabetes
Women who have had gestational diabetes face significantly elevated risk of developing type 2 diabetes later in life. Metformin should be considered in those with prediabetes, especially those with a BMI ≥35 kg/m2, younger individuals, and women with a history of gestational diabetes. For this population, early intervention with both lifestyle modifications and potentially medication can be particularly important.
Younger Adults
Metformin had a selectively greater effect in those who were more obese, had a higher fasting glucose, had a history of gestational diabetes, or were younger. Younger individuals with prediabetes may benefit more from medication intervention, possibly because they have more years of potential diabetes exposure ahead of them, making prevention particularly valuable.
Individuals with Very High BMI
People with BMI ≥35 kg/m² represent a particularly high-risk group. For these individuals, the combination of lifestyle intervention and medication may be most appropriate from the outset. In some cases, bariatric surgery may also be considered as part of a comprehensive treatment approach.
Perimenopausal Women
Despite this growing issue, there hasn’t been much research focused on prediabetes in women going through menopause and how the changes in hormones might affect treatment guidelines, with review focused on the use of metformin for women in the perimenopausal stage with prediabetes, aiming to help prevent them from developing T2D in the future. Hormonal changes during perimenopause can affect insulin sensitivity and weight distribution, potentially increasing diabetes risk.
Children and Adolescents
The CDC reports that 18% of adolescents have prediabetes, and it’s on the rise in that group. While this review focuses on the adult population, there is evidence emerging about prediabetes in children, including risk factors, consequences, and consideration of similar strategies. The approach to prediabetes in children and adolescents requires special consideration, with emphasis on family-based lifestyle interventions.
The Interprofessional Approach to Prediabetes Care
This is best done in an interprofessional fashion that involves an endocrinologist, bariatric surgeon, dietitian, pharmacists, weight loss nurse, and a physical therapist. A team-based approach to prediabetes management can provide comprehensive support and improve outcomes.
Key Team Members
An effective prediabetes care team may include:
- Primary care physician: Coordinates overall care, orders screening tests, and manages medication prescriptions
- Endocrinologist: Provides specialized expertise in metabolic disorders and complex cases
- Registered dietitian: Develops personalized nutrition plans and provides ongoing dietary counseling
- Certified diabetes educator: Teaches self-management skills and provides education about prediabetes
- Exercise physiologist or physical therapist: Designs safe and effective exercise programs
- Pharmacist: Provides medication counseling and monitors for drug interactions
- Mental health professional: Addresses psychological barriers to lifestyle change and manages stress
- Bariatric surgeon: Evaluates surgical options for appropriate candidates
Lifestyle Medicine Approach
Lifestyle medicine, emphasizing all its pillars, involves collaborating with a team of interprofessional health care practitioners who educate on physical activity and healthy eating, while also addressing sleep, stress, substance use, and social connections. This holistic approach recognizes that health behaviors are interconnected and that addressing multiple lifestyle factors simultaneously may be more effective than focusing on diet and exercise alone.
Cost-Effectiveness and Access Considerations
Data from the DPP and DPPOS suggesting that over 10 years, metformin treatment is cost-saving, decreasing the cumulative costs of medical care received outside the DPP and DPPOS compared with placebo. This cost-effectiveness makes metformin an attractive option from a healthcare economics perspective.
However, access to both lifestyle interventions and medications can be challenging for some populations. Barriers may include:
- Lack of insurance coverage for preventive services
- High out-of-pocket costs for medications or structured lifestyle programs
- Limited access to healthcare providers, particularly in rural areas
- Food insecurity and limited access to healthy foods
- Lack of safe spaces for physical activity
- Time constraints due to work or family obligations
- Language or cultural barriers to healthcare access
Addressing these barriers requires systemic changes at the healthcare system and policy levels, as well as creative solutions at the individual and community levels.
Future Directions in Prediabetes Treatment
Research continues to evolve our understanding of prediabetes and optimal treatment approaches. Currently, there are no global guidelines for managing prediabetes, and the use of metformin in prediabetes is largely based on clinical experience, and there is a lack of high-quality evidence-based medicine.
Areas of Ongoing Research
Current research is exploring:
- Optimal dosing strategies for metformin in prediabetes
- Long-term cardiovascular outcomes with prediabetes treatment
- Role of newer medications (GLP-1 receptor agonists, SGLT2 inhibitors) in prediabetes prevention
- Genetic and biomarker-based approaches to identify who will benefit most from medication
- Digital health interventions for lifestyle modification
- Optimal duration of medication treatment
- Effects of prediabetes treatment on microvascular complications
Personalized Medicine Approaches
Future treatment may become increasingly personalized based on individual risk profiles, genetic factors, and metabolic characteristics. This could allow for more targeted interventions that maximize benefit while minimizing unnecessary treatment.
Digital Health Tools
The DPP consists of an intensive 16-week healthy lifestyle intervention followed by a maintenance phase, administered via smartphone or computer. Digital platforms, mobile apps, continuous glucose monitors, and telemedicine are making prediabetes management more accessible and providing new tools for monitoring and intervention.
Making Informed Decisions About Prediabetes Treatment
In summary, metformin is safe and effective in preventing or delaying type 2 diabetes in adults at high risk of diabetes, with a comparable effect to lifestyle intervention seen in specific subgroups (i.e., those who are more obese, younger, or have a history of gestational diabetes), and with the growing impact of prediabetes and diabetes worldwide, a greater systematic effort to address the remaining gaps and translate the current evidence is essential and perhaps overdue.
When considering whether medication is appropriate for prediabetes management, individuals should discuss the following with their healthcare provider:
- Individual risk factors and likelihood of progression to diabetes
- Previous attempts at lifestyle modification and barriers encountered
- Potential benefits and risks of medication
- Personal preferences and values regarding medication use
- Available support systems for lifestyle changes
- Financial considerations and insurance coverage
- Commitment to ongoing monitoring and follow-up
Prediabetes is a warning sign, but it is also an opportunity, and even small lifestyle changes can improve blood sugar levels and help prevent the progression to diabetes, with many people being able to delay or prevent diabetes and protect their long-term health by taking action early.
Conclusion: A Comprehensive Approach to Prediabetes
Prediabetes represents a critical window of opportunity for preventing type 2 diabetes and its associated complications. While lifestyle modifications remain the foundation of treatment, medications—particularly metformin—play an important role for specific high-risk individuals. The decision to use medication should be individualized, taking into account risk factors, previous lifestyle modification attempts, patient preferences, and the potential benefits and risks.
While some individuals with prediabetes may never progress to diabetes or the multitude of complications impacting most organs in the body, there is ample evidence that shows the impact of hyperglycemia and renal-cardio-metabolic connection on morbidity and mortality-related patient outcomes. This underscores the importance of taking prediabetes seriously and implementing appropriate interventions.
The most effective approach combines evidence-based lifestyle modifications with appropriate use of medications when indicated, delivered through an interprofessional team that provides comprehensive support. Regular monitoring and follow-up ensure that treatment plans remain effective and can be adjusted as needed. With proper management, many individuals with prediabetes can prevent or significantly delay the onset of type 2 diabetes, improving their long-term health outcomes and quality of life.
For more information about diabetes prevention and management, visit the CDC’s Diabetes Prevention Program or consult with your healthcare provider about personalized screening and treatment options. The American Diabetes Association also provides extensive resources for individuals with prediabetes and their families.