Objective:

To evaluate the efficacy of oral diacerein in reducing knee pain in patients with symptomatic knee osteoarthritis and effusion-synovitis detected on MRI, highlighting its potential impact on treatment strategies.

Key Findings:

• Mean VAS scores decreased by 19.9 mm in the diacerein group and 18.6 mm in the placebo group, with a between-group difference of -1.3 mm.
• Secondary outcomes showed similar results between groups for pain and function scores.
• MRI findings indicated no structural improvement; effusion-synovitis volume increased in the diacerein group.
• Quality-of-life measures favored placebo, with significant differences in scores.
• Adverse events were more frequent in the diacerein group, particularly gastrointestinal symptoms, affecting treatment adherence.

Interpretation:

Diacerein did not provide significant pain relief compared to placebo in patients with knee OA and effusion-synovitis, despite targeting an inflammatory phenotype, suggesting a need for alternative therapies.

Limitations:

• MRI evidence of effusion-synovitis was obtained without contrast, limiting differentiation between synovial thickening and joint effusion, which may affect the study's conclusions.
• Results may not generalize to patients without inflammatory features of OA, indicating a need for further research in diverse populations.

Conclusion:

Diacerein (50 mg, twice daily) over 24 weeks resulted in no greater improvement in knee pain compared with placebo in patients with symptomatic knee OA and effusion-synovitis, raising questions about its efficacy as a treatment option.