- Design
- Double-blind, placebo-controlled randomised trial
- Population
- 120 adults with symptomatic knee OA, Kellgren–Lawrence grade 2–3
- Primary outcome
- Change in index knee pain (VAS) at 3 months
- Effect
- No significant difference in pain, KOOS or effusion; hsCRP lowered
The CLOAK double-blind trial, published in Seminars in Arthritis and Rheumatism on 23 August, randomised 120 people with symptomatic knee osteoarthritis (Kellgren–Lawrence grade 2 or 3) to daily colchicine or placebo for three months, without NSAIDs.
There was no difference in knee pain, KOOS function scores or ultrasound effusion size. Subgroups with worse pain, more advanced radiographic disease, or higher CRP or urate also showed no benefit. Colchicine did lower some inflammatory markers, including hsCRP.
Colchicine is sometimes tried for inflammatory-looking osteoarthritis. This trial does not support it for symptom relief, and biomarker changes are not a reason to prescribe.
- Do not prescribe colchicine for knee osteoarthritis pain; it did not help in this trial.
- Consider gout or calcium pyrophosphate disease if a knee is acutely inflamed — that is where colchicine has a role.
- Keep exercise, weight management and topical NSAIDs as the core of osteoarthritis care.
- Be cautious about lowered biomarkers presented as evidence of benefit.
Why it matters
It removes a speculative option often tried when osteoarthritis looks inflammatory.
The statistics, in plain English
Biomarker improvements are surrogate outcomes; without a change in pain or function, they do not show clinical benefit.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for rheumatology, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free