Background: Acupuncture is widely used for the treatment of chronic pain. Different protocols of acupuncture practice exist and lack agreement on the optimal schedule of acupuncture treatment.
Objective: To review the appropriate acupuncture treatment schedule for chronic pain.
Methods: Embase, Pubmed, Cochrane Central Register of Controlled Trials, and reference lists were searched from 2009 to 2018 to identify randomized controlled trials of acupuncture for chronic pain conditions. We collected factors of treatment schedule (D, duration of each treatment session; N, number of treatment sessions; T, total duration of treatment in weeks) from each of the trials, and the linear regression analysis with real pain relief rate (both treatment and follow-up) was performed. Furthermore, we recommend the concept of "DOSE" and frequency (F) to evaluate the dose and frequency effect of acupuncture.
Results: Twenty-four trials with a total number of 3461 patients met the inclusion criteria. Of these, data from 23 studies were available for analysis. Firstly, the results showed that follow-up pain relief rate was decreased slightly with the increase of the duration of each session and DOSE (r=-0.3414 and r=-0.3246, respectively), but those two factors had no correlation with the pain relief rate after treatment. Secondly, it showed that either lower frequency with 2 sessions/week and higher frequency greater than 2 sessions/week or DOSE of 30 mins/week can achieve higher pain relief rate after treatment. Thirdly, we found the rate of pain relief remained at a high level greater than 20% up to 18 weeks after the treatment, and then it dropped sharply below 10% with the follow-up extended. A positive relationship was found between study score and pain relief both in treatment and follow-up (r=0.4654 and r=0.3046, respectively).
Conclusions: The effect of acupuncture varies greatly with the different schedules of acupuncture, so it is necessary to review and choose the appropriate schedule. Although the current work is based on a limited number of trials, the findings suggest that acupuncture has a dose and frequency effect presenting within a certain range, which would have considerable implications for the design and interpretation of clinical trials. More high-quality randomized controlled trials on acupuncture schedule research were needed for providing more definitive evidence.