Efficacy and safety of collagen derivatives for osteoarthritis: A trial sequential meta-analysis

Liang CW, Cheng HY, Lee YH, Liao CD, Huang SW · Osteoarthritis and Cartilage

The largest and most rigorous synthesis in the field. Pain SMD -0.35 (95% CI -0.48 to -0.22, moderate certainty) and function SMD -0.31 (-0.41 to -0.22, high certainty), with no excess withdrawals or adverse events. Trial sequential analysis confirmed the information size was reached. The authors call this strong evidence; note the effect sizes themselves are small, below the 0.5 conventionally treated as clinically meaningful.

Population

35 randomized controlled trials of collagen derivatives in osteoarthritis; primary analysis on 25 RCTs and 2856 patients

Intervention

Collagen derivatives (hydrolysates, gelatin, undenatured type II)

Comparator

Placebo or control

Limitations

Pools heterogeneous products and doses spanning 40 mg undenatured type II to 10 g hydrolysate, with mutually incompatible proposed mechanisms. Inherits the risk of bias of a literature that is overwhelmingly industry-funded.