Obesity and weight management — KFP-style written assessment

KFP 1 (10 marks)

A 48-year-old man with BMI 33 and prediabetes (HbA1c 6.0%) attends for review. He has tried multiple commercial diets with temporary success followed by regain. He asks whether there is 'anything that actually works'. ^[1]

1. What does the DPP tell you about intensive lifestyle intervention for prediabetes? Quantify the results. (5) ^[1]
2. What weight-loss target would you set and why? (3) ^[1]
3. Would you add metformin? Justify. (2) ^[1]

Model answers

1. The DPP randomised 3234 adults with prediabetes to intensive lifestyle intervention (goal: ≥7% weight loss and ≥150 min/week activity), metformin 850 mg BD or placebo over mean 2.8 years follow-up. Lifestyle reduced incident T2DM by 58% (95% CI 48–66%) versus placebo; metformin reduced it by 31%. NNT was 6.9 for lifestyle over three years — this is powerful prevention medicine. ^[1]
2. Set 5–10% body-weight loss as the initial target. The DPP used a 7% goal; this magnitude of loss delivers clinically meaningful improvements in glycaemia, blood pressure and lipids without requiring normalisation of BMI. More is better but not required for clinical impact. ^[1]
3. Yes, consider metformin 850 mg twice daily — it reduced incidence by 31% in DPP (NNT 13.9) and may suit a patient who cannot commit to intensive lifestyle change immediately. Lifestyle was significantly more effective than metformin but both beat placebo. ^[1]