OBJECTIVES: 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.
PATIENTS AND METHODS: 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.
RESULTS: 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.
DISCUSSION: 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.
UNLABELLED: Cannabis is widely used as a self-management strategy by patients with a wide range of symptoms and diseases including chronic non-cancer pain. The safety of cannabis use for medical purposes has not been systematically evaluated. We conducted a prospective cohort study to describe safety issues among individuals with chronic non-cancer pain. A standardized herbal cannabis product (12.5% tetrahydrocannabinol) was dispensed to eligible individuals for a 1-year period; controls were individuals with chronic pain from the same clinics who were not cannabis users. The primary outcome consisted of serious adverse events and non-serious adverse events. Secondary safety outcomes included pulmonary and neurocognitive function and standard hematology, biochemistry, renal, liver, and endocrine function. Secondary efficacy parameters included pain and other symptoms, mood, and quality of life. Two hundred and fifteen individuals with chronic pain were recruited to the cannabis group (141 current users and 58 ex-users) and 216 controls (chronic pain but no current cannabis use) from 7 clinics across Canada. The median daily cannabis dose was 2.5 g/d. There was no difference in risk of serious adverse events (adjusted incidence rate ratio = 1.08, 95% confidence interval = .57-2.04) between groups. Medical cannabis users were at increased risk of non-serious adverse events (adjusted incidence rate ratio = 1.73, 95% confidence interval = 1.41-2.13); most were mild to moderate. There were no differences in secondary safety assessments. Quality-controlled herbal cannabis, when used by patients with experience of cannabis use as part of a monitored treatment program over 1 year, appears to have a reasonable safety profile. Longer-term monitoring for functional outcomes is needed.
STUDY REGISTRATION: The study was registered with www.controlled-trials.com (ISRCTN19449752).
PERSPECTIVE: This study evaluated the safety of cannabis use by patients with chronic pain over 1 year. The study found that there was a higher rate of adverse events among cannabis users compared with controls but not for serious adverse events at an average dose of 2.5 g herbal cannabis per day.
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.
PATIENTS AND METHODS:
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.
RESULTS:
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.
DISCUSSION:
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.
