To optimally select chronic pain patients for different treatments, as it is of interest to identify patient characteristics that might moderate treatment effect. Our aim was to evaluate the impact of possible moderators on the effect of acupuncture treatment using a large data set.
We used data from an individual patient data meta-analysis of high-quality randomized trials of acupuncture for chronic headache and migraine, osteoarthritis, and back, neck, and shoulder pain. Using meta-analytic trial-level and patient-level regression analyses, we explored the impact of 5 documented patient characteristics (patients’ age at baseline, sex, pain duration, baseline pain severity and baseline psychological distress) on the effect of acupuncture.
A total of 39 trials met the inclusion criteria: 25 use sham-acupuncture controls (n = 7097) and 25 non-acupuncture controls (n = 16,041). Of the 5 patient characteristics analyzed, only baseline pain severity was found to potentially moderate the treatment effect of acupuncture, with patients reporting more severe pain at baseline experiencing more benefit from acupuncture compared to either sham-control or non-acupuncture control. Baseline psychological distress showed small treatment moderating effects, and results for sex were inconsistent. There was no strong evidence that age or duration of pain influenced the response to acupuncture.
Of 5 patient characteristics tested, we found only baseline severity of pain to potentially moderate the effect of acupuncture treatment. For clinical practice, the evidence from this analysis does not justify stratifying chronic pain patients into subgroups that should or should not receive acupuncture on the basis of these 5 characteristics. Future acupuncture trials should assess other potentially important effect moderators.
*Institute for Complementary and Integrative Medicine, University of Zurich and University Hospital Zurich, Zurich, Switzerland
†Institute for Social Medicine, Epidemiology, and Health Economics, Charité—Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin
#TUM Medical School, Institute of General Practice, Technical University Munich, Munich, Germany
‡Center for Integrative Medicine, University of Maryland School of Medicine, Baltimore, MD
§Memorial Sloan Kettering Cancer Center, New York, NY
∥Arthritis Research UK Primary Care Centre, Research Institute of Primary Care & Health Sciences, Keele University, Staffordshire
¶Primary Care and Population Sciences, Faculty of Medicine, University of Southampton, Southampton
**Department of Health Sciences, University of York, York, UK
††Kaiser Permanente Washington Health Research Institute and University of Washington, Seattle, WA
✠ George Lewith deceased.
A.J.V., G.L., C.M.W., and K.L.: conceived the main study. A.J.V., E.A.V., and C.M.W.: were responsible for the overall design of the analyses; all other authors provided knowledge on details of the analyses. E.A.V.: conducted the statistical analyses. C.M.W., E.A.V., and A.J.V.: wrote the first draft of the manuscript. All authors gave comments on early drafts and approved the final version of the manuscript. A.J.V.: had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
The views expressed in this publication are those of the author(s) and not necessarily those of the National Center for Complementary and Alternative Medicine, National Health Service (NHS), NIHR, or the Department of Health in England.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the report.
The Acupuncture Trialists’ Collaboration is funded by an R21 (AT004189I and an R01 (AT006794) from the National Center for Complementary and Alternative Medicine at the National Institutes of Health, Bethesda, MD to A.J.V.) and by a grant from the Samueli Institute, Alexandria, VA. H.M.P.’s work on this project was funded in part by the National Institute for Health Research, London, UK (NIHR) under its Program Grants for Applied Research scheme (RP-PG-0707-10186). N.E.F., an NIHR Senior Investigator, was supported through an NIHR Research Professorship (RP-011-015). The authors declare no conflict of interest.
Reprints: Claudia M. Witt, MD, MBA, Institute for Complementary and Integrative Medicine, University Hospital and University of Zurich, Sonneggstrasse 6, Zurich 8091, Switzerland (e-mail: email@example.com).
Received July 12, 2018
Received in revised form December 13, 2018
Accepted January 15, 2019