How many patients need to be treated with semaglutide (generic name) plus lifestyle modification for 68 weeks to achieve at least a 10% reduction in body weight?

Number Needed to Treat with Semaglutide for 10% Weight Loss is 2

Based on the STEP-1 study data, the number needed to treat (NNT) with semaglutide plus lifestyle modification for 68 weeks for one patient to achieve at least a 10% reduction in body weight is 2.

Calculation of NNT

To calculate the NNT, we need to determine the absolute risk reduction (ARR) between the treatment and control groups, and then calculate 1/ARR:

1. In the semaglutide group, 69.1% of patients achieved ≥10% weight loss
2. In the placebo group, 12.0% of patients achieved ≥10% weight loss
3. Absolute risk reduction (ARR) = 69.1% - 12.0% = 57.1%
4. NNT = 1/ARR = 1/0.571 = 1.75, which rounds to 2

Clinical Significance of Semaglutide for Weight Loss

Semaglutide represents a significant advancement in pharmacological treatment for obesity. The STEP-1 trial demonstrated that semaglutide 2.4 mg administered once weekly produces substantial weight loss compared to placebo when combined with lifestyle interventions 1:

• Mean weight change from baseline at 68 weeks: -14.9% with semaglutide vs. -2.4% with placebo
• Proportion achieving ≥10% weight loss: 69.1% with semaglutide vs. 12.0% with placebo

Cardiometabolic Benefits

Beyond weight loss, semaglutide provides important cardiometabolic benefits 1:

• Improved blood pressure
• Reduced fasting blood glucose
• Decreased LDL cholesterol
• Enhanced physical functioning

Adverse Effects and Considerations

The most common adverse effects with semaglutide are gastrointestinal 1:

• 74.2% of semaglutide patients reported gastrointestinal effects vs. 47.9% in the placebo group
• 7.0% of semaglutide patients discontinued treatment due to adverse effects vs. 3.1% in the placebo group
• Most common symptoms include nausea, vomiting, diarrhea, and constipation

Clinical Application and Guidelines

Current guidelines support the use of GLP-1 receptor agonists like semaglutide for patients with:

• BMI ≥30 kg/m² or ≥27 kg/m² with weight-related comorbidities 2
• Documented history of failed weight loss attempts through lifestyle modifications 2

For semaglutide specifically, the recommended dosing protocol involves:

• Starting at 0.25 mg weekly
• Gradually increasing to 2.4 mg weekly maintenance dose 2

Monitoring and Continuation Criteria

Treatment should be discontinued if:

• 5% weight loss is not achieved at 12 weeks on the maintenance dose 2
• Intolerable side effects develop

For responders, treatment should be continued indefinitely to prevent weight regain 2.

Conclusion

With an NNT of 2 for achieving ≥10% weight loss, semaglutide represents one of the most effective pharmacological interventions for obesity management currently available. This low NNT demonstrates the high clinical efficacy of semaglutide when combined with lifestyle modifications for treating obesity.