What are the recommended lifestyle modifications and medications for managing prediabetes?

Prediabetes Education: Lifestyle Modifications and Medications

All individuals with prediabetes (A1C 5.7-6.4%, fasting glucose 100-125 mg/dL, or 2-hour glucose 140-199 mg/dL) should be referred to an intensive lifestyle behavior change program targeting at least 7% weight loss and 150 minutes per week of moderate-intensity physical activity, with metformin considered for high-risk patients (BMI >35 kg/m², age <60 years, or women with prior gestational diabetes). 1

Lifestyle Modifications: First-Line Treatment

Weight Loss Goals

• Target a minimum of 7% body weight reduction through calorie restriction and increased physical activity 1
• Even modest weight loss of 5% improves insulin resistance and reduces diabetes risk 1
• The Diabetes Prevention Program demonstrated a 58% reduction in diabetes incidence over 3 years with intensive lifestyle intervention, with sustained benefits of 27-43% risk reduction persisting for 7-30 years 1, 2

Physical Activity Requirements

• Perform at least 150 minutes per week of moderate-intensity physical activity (such as brisk walking), distributed throughout the week with no more than 2 consecutive days without exercise 1, 3
• Break up sedentary periods of 30 minutes or more with brief standing or light activity 3
• Resistance training 2-3 sessions weekly on non-consecutive days further improves glycemic control 3

Dietary Recommendations

• Emphasize nutrient-dense, minimally processed foods: nonstarchy vegetables, whole fruits, legumes, whole grains, nuts/seeds, and low-fat dairy products 1
• Minimize or eliminate sugar-sweetened beverages (including fruit juices), refined grains, sweets, and ultraprocessed foods 1
• Reduce total calorie intake by 500-1,000 calories daily from maintenance levels to achieve 1-2 pounds per week weight loss 1
• No single macronutrient distribution is ideal; individualize based on preferences while maintaining calorie goals 1
• Mediterranean-style, low-carbohydrate, DASH, and plant-based eating patterns are all acceptable options 1

Program Structure and Support

• Enroll in a CDC-recognized Diabetes Prevention Program or equivalent intensive behavioral counseling program with frequent follow-up 1
• Programs should include individualized meal planning, self-monitoring, motivational support, and regular contact to maintain adherence 1
• Group delivery in community settings can be cost-effective while achieving similar weight loss outcomes 1

Pharmacotherapy: When and Who

Metformin Indications

Metformin should be considered for prediabetes in the following high-risk groups: 1

• BMI ≥35 kg/m² (metformin was as effective as lifestyle modification in this group) 1
• Age <60 years (metformin showed no significant benefit over placebo in those ≥60 years) 1
• Women with prior gestational diabetes (metformin achieved 50% diabetes risk reduction, equivalent to lifestyle intervention) 1
• Fasting plasma glucose ≥110 mg/dL or A1C ≥6.0% 2

Metformin Efficacy

• Reduces diabetes incidence by 3.2 cases per 100 person-years over 3 years (31% relative risk reduction) 2
• Less effective than lifestyle modification overall but cost-saving over 10 years 1
• Has the strongest evidence base and demonstrated long-term safety among pharmacological options 1

Alternative Medications

While other agents have shown efficacy in clinical trials, metformin remains the only medication with strong guideline support for prediabetes prevention 1:

• Acarbose, pioglitazone, rosiglitazone, nateglinide, and liraglutide have demonstrated benefits in research settings 4, 5
• However, cost, side effects, and lack of persistent effect after discontinuation limit their routine use 1
• Thiazolidinediones (pioglitazone) may be considered for high-risk patients who progress despite intensive lifestyle modification 4

Medical Nutrition Therapy

Refer all individuals with prediabetes to a registered dietitian nutritionist for individualized medical nutrition therapy 1

• MNT delivered by a registered dietitian achieves A1C reductions of 0.3-2% in type 2 diabetes and is effective in lowering A1C in prediabetes 1
• MNT is cost-effective and should be adequately reimbursed by insurance 1

Monitoring and Follow-Up

• Monitor for diabetes development at least annually with fasting glucose, 2-hour glucose tolerance test, or A1C 1
• Screen for and treat cardiovascular risk factors (hypertension, dyslipidemia, smoking) as these patients have increased cardiovascular disease risk 1, 2
• Provide ongoing support and follow-up, as sustained behavior change requires continued reinforcement 1

Common Pitfalls to Avoid

• Don't delay intervention: Prediabetes is associated with increased mortality (7.36 excess deaths per 10,000 person-years) and cardiovascular events (8.75 excess events per 10,000 person-years) 2
• Don't prescribe metformin alone without lifestyle intervention: Lifestyle modification produces greater absolute risk reduction (6.2 vs 3.2 cases per 100 person-years) 2
• Don't use metformin as first-line in patients ≥60 years with BMI <35: It showed no significant benefit over placebo in this population 1
• Don't forget cardiovascular risk factor management: These patients require the same aggressive treatment of hypertension and dyslipidemia as those with established diabetes 1
• Don't underestimate the importance of program intensity: Frequent follow-up and ongoing support are critical for sustained weight loss and behavior change 1