A 48-year-old woman has a normal complete blood count, hemoglobin A1c 5.8% and fasting plasma glucose 109 mg/dL (prediabetes). How should I manage her?

Management of Prediabetes in a 48-Year-Old Woman

This patient has prediabetes based on both HbA1c 5.8% and fasting glucose 109 mg/dL, and should be counseled on intensive lifestyle modification including weight loss of 7% of body weight and 150 minutes per week of moderate-intensity physical activity, with annual screening for progression to diabetes. 1

Confirming the Diagnosis

• HbA1c 5.8% meets criteria for prediabetes (defined as 5.7-6.4%), placing this patient at very high risk for developing diabetes 1

• Fasting glucose 109 mg/dL confirms prediabetes (defined as 100-125 mg/dL by ADA criteria), providing concordant evidence 1

• The combination of both abnormal tests strengthens the diagnosis, as using HbA1c and fasting glucose together identifies significantly more cases of prediabetes than either test alone 2, 3

• Individuals with HbA1c 5.7-6.4% have a 5-year cumulative diabetes incidence of 12-25%, which is 3-8 fold higher than the general population 1

• Those with HbA1c above 6.0% should be considered at very high risk and warrant the most intensive interventions and vigilant follow-up 1

Complete Blood Count Interpretation

• The CBC is entirely normal with lymphocyte percentage 12.4%, neutrophil percentage 76.2%, MPV 7.1, RBC 4.38, and WBC 7.0 1

• Normal hemoglobin and red blood cell indices confirm that HbA1c is reliable in this patient, as there are no conditions affecting red cell turnover that would falsely lower or elevate the result 4, 5, 6

• The absence of anemia rules out iron deficiency (which falsely elevates HbA1c) and hemolytic conditions (which falsely lower HbA1c) 4, 5

Primary Management Strategy

Lifestyle Intervention (First-Line Treatment)

• Prescribe structured weight loss of 7% of current body weight through caloric restriction, as this is the evidence-based target from diabetes prevention trials 1

• Prescribe 150 minutes per week of moderate-intensity physical activity (such as brisk walking), distributed over at least 3 days per week with no more than 2 consecutive days without activity 1

• Provide medical nutrition therapy by a registered dietitian experienced in diabetes prevention, ideally at diagnosis and annually thereafter 1

• Emphasize that lifestyle interventions can reduce progression to diabetes by up to 58% in high-risk individuals 1

Cardiovascular Risk Factor Management

• Screen for and aggressively manage hypertension and dyslipidemia, as these often coexist with prediabetes and take priority over glycemic control for preventing macrovascular complications 1

• Counsel on smoking cessation if applicable, as tobacco use compounds cardiovascular risk 1

• Assess for other cardiovascular risk factors including family history and calculate 10-year cardiovascular risk 1

Monitoring and Follow-Up

• Rescreen annually with HbA1c and/or fasting glucose to detect progression to diabetes 1

• At each visit, reassess adherence to lifestyle modifications and provide ongoing behavioral support 1

• Consider more frequent screening (every 6 months) given that this patient's HbA1c of 5.8% is in the higher range of prediabetes 1

Pharmacologic Considerations

• Metformin may be considered in patients with prediabetes who are at very high risk (HbA1c ≥6.0%, age <60 years, BMI ≥35 kg/m², history of gestational diabetes), though lifestyle modification remains first-line 1

• The decision to use metformin should be individualized based on additional risk factors not provided in this case (BMI, history of gestational diabetes) 1

Critical Pitfalls to Avoid

• Do not dismiss prediabetes as "borderline" or insignificant—this patient has a 12-25% risk of developing diabetes within 5 years and requires active intervention 1

• Do not delay lifestyle counseling while waiting to see if glucose worsens; intervention is most effective when started early 1

• Do not focus solely on glycemic control while neglecting blood pressure and lipid management, which have greater impact on cardiovascular outcomes in this population 1

• Do not use point-of-care HbA1c devices for diagnostic or monitoring purposes, as they lack sufficient accuracy 1, 4

• Do not assume HbA1c alone is sufficient for diagnosis—this patient's concordant fasting glucose strengthens the diagnosis, but be aware that HbA1c identifies approximately one-third fewer cases than fasting glucose in population screening 1