The objective of this prospective, open-label study was to determine the long-term effect of medicinal cannabis treatment on pain and functional outcomes in participants with treatment-resistant chronic pain.
The primary outcome was the change in the pain symptom score on the S-TOPS (Treatment Outcomes in Pain Survey—Short Form) questionnaire at the 6-month follow-up in an intent-to-treat population. Secondary outcomes included the change in S-TOPS physical, social, and emotional disability scales, the pain severity, and pain interference on the Brief Pain Inventory, sleep problems, and the change in opioid consumption.
A total of 274 participants were approved for treatment; complete baseline data were available for 206 (intent-to-treat), and complete follow-up data for 176 participants. At follow-up, the pain symptom score improved from median 83.3 (95% confidence interval [CI], 79.2-87.5) to 75.0 (95% CI, 70.8-79.2) (P<0.001). The pain severity score (7.50 [95% CI, 6.75-7.75] to 6.25 [95% CI, 5.75-6.75]) and the pain interference score (8.14 [95% CI, 7.28-8.43] to 6.71 [95% CI, 6.14-7.14]) improved (both P<0.001), together with most social and emotional disability scores. Opioid consumption at follow-up decreased by 44% (P<0.001). Serious adverse effects led to treatment discontinuation in 2 participants.
The treatment of chronic pain with medicinal cannabis in this open-label, prospective cohort resulted in improved pain and functional outcomes, and a significant reduction in opioid use. Results suggest long-term benefit of cannabis treatment in this group of patients, but the study’s noncontrolled nature should be considered when extrapolating the results.
*Pain Relief Unit
‡Department of Anesthesia and Critical Care Medicine, Hadassah-Hebrew University Medical Center
§Hadassah School of Dental Medicine, Hebrew University, Jerusalem, Israel
†Department of Anesthesiology, Division of Clinical and Translational Research, Washington University School of Medicine, Saint Louis, MO
The study did not have external funding, and was performed only with internal support from the Hadassah-Hebrew University Pain Relief Unit, Jerusalem, Israel. The authors declare no conflicts of interest to declare.
Reprints: Elyad Davidson, MD, Pain Relief Unit, Department of Anesthesia and Critical Care Medicine, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel (e-mail: firstname.lastname@example.org).
Received October 20, 2015
Received in revised form April 5, 2016
Accepted February 1, 2016