Summary:
In 407 adults with obesity (BMI ≥30) and moderate knee osteoarthritis (Kellgren-Lawrence 2-3), mean age 56, 81.6% female, once-weekly semaglutide 2.4 mg for 68 weeks plus lifestyle counseling produced 13.7% weight loss vs 3.2%, WOMAC pain improvement 41.7 vs 27.5 points (difference 14.1, P<0.001), improved physical function, and reduced analgesic use compared to matching placebo with identical lifestyle counseling, with GI side effects leading to 6.7% vs 3.0% discontinuation.
| PICO | Description |
|---|---|
| Population | 407 adults with obesity (BMI ≥30) and moderate knee OA (KL grade 2-3), mean age 56, 82% female. |
| Intervention | Semaglutide 2.4 mg weekly for 68 weeks + lifestyle counseling. |
| Comparison | Matching placebo + identical lifestyle counseling. |
| Outcome | Weight -13.7% vs -3.2%. WOMAC pain +14.1 points difference. Reduced analgesic use. |
STEP 9: Semaglutide in Obesity & Knee Osteoarthritis
RCT · obesity + knee OA · 68 weeks
Once-weekly semaglutide 2.4 mg produced clinically meaningful weight loss and WOMAC pain reduction versus placebo in obesity-related knee osteoarthritis.
Clinical Context
Obesity increases mechanical loading and produces inflammatory cytokines causing synovitis. Pain limits exercise, creating a vicious cycle.
Clinical Pearls
1. Weight Loss Produces Meaningful Pain Reduction: 14-point WOMAC difference exceeds 10-point clinical significance threshold.
2. Analgesic Use Decreased: Reduced NSAID use means lower GI, CV, and kidney risks.
3. Breaking the Obesity-OA Cycle: Achieves weight loss without exercise capacity that patients lack.
4. Predominantly Female Population: 82% female reflects real-world OA epidemiology.
Practical Application
Consider for knee OA + BMI ≥30 when traditional weight loss fails or pain limits exercise. Maximum benefit requires 6-12 months.
Study Limitations
No structural imaging endpoints. 68-week duration. Lifestyle adherence not formally assessed.
Bottom Line
Semaglutide produces clinically meaningful OA pain reduction and weight loss, offering disease-modifying approach for obesity-related joint disease.
Source: Bliddal H, et al. “Semaglutide in Obesity and Knee Osteoarthritis (STEP 9).” NEJM, 2024. Read article