A meta-analysis of 17,922 patients from randomized controlled trials “provided the most robust evidence to date that acupuncture is a reasonable referral option for patients with chronic pain”. The chronic pain conditions included musculoskeletal pain (low back, neck, and shoulder), osteoarthritis of the knee, and headache/migraine. Publisched in: Vickers et al. 2012 Archives of Internal Medicine 172(19):1444-53.
A follow up study analysed this data for long-term pain relief. Benefits of acupuncture persisted 12 months after treatment ended. The researchers concluded “The effects of a course of acupuncture treatment for patients with chronic pain do not seem to decrease importantly over 12 months. Patients can generally be reassured that treatment effects persist. Studies of the cost-effectiveness of acupuncture should take our findings into account when considering the time horizon of acupuncture effects. Further research should measure longer term outcomes of acupuncture.” Published in MacPherson et al. 2017 Pain 158(5):784–793.