Different Effects with Different Placebos in Knee Osteoarthritis

The efficacy of placebos is well documented, but whether different placebo types have different effects is unclear. In this systematic review and network meta-analysis (i.e., analysis in which directly and indirectly compared treatments in a set of studies are combined), researchers assessed the relative effects of various placebos on pain outcomes in patients with knee osteoarthritis. Analysis involved 149 randomized trials in which widely used pharmaceuticals were compared with one of four types of placebo: oral, intra-articular, topical, or oral plus topical. Active comparators included acetaminophen, selective and nonselective nonsteroidal anti-inflammatory drugs (NSAIDs), topical NSAIDs, intra-articular steroids, and intra-articular hy…