Comparative Effectiveness of Spinal Manipulation for Low Back Pain: A Bayesian Hierarchical Analysis Incorporating Natural History

The study analyzed 120 randomized controlled trials involving 19,059 patients to compare the effectiveness of spinal manipulation, exercise, medical management, and other treatments for low back pain. Researchers found that in acute low back pain, most improvement by 26 weeks is explained by natural healing regardless of treatment. In chronic low back pain, improvement was slower, but spinal manipulation and exercise showed positive effects that were modest and often did not exceed clinical importance thresholds. Control groups achieved better results than natural history, indicating a substantial placebo effect. The study concluded that most observed improvement in acute pain is due to natural healing, while in chronic pain, contextual and placebo effects play a significant role.