Systematic Review Finds Insufficient Evidence for Cannabinoids in Rheumatic Pain | Research

The takeaway

A systematic review of randomized controlled trials found some potential for cannabinoids to help with pain and sleep in rheumatic conditions, but the evidence base was too small and short-term to support clinical recommendations.

Read this if you have a rheumatic condition and are considering cannabinoids for pain management.

Only 4 small trials with fewer than 200 total patients across all rheumatic conditions

What the researchers found

The researchers systematically searched for randomized controlled trials of cannabinoid products in fibromyalgia, osteoarthritis, chronic spinal pain, and rheumatoid arthritis. They found remarkably little evidence.

Only four short trials qualified: two in fibromyalgia (71 patients total, using nabilone), one in spinal pain (30 patients, nabilone), and one in rheumatoid arthritis (58 patients, THC/CBD). No trials in osteoarthritis met inclusion criteria.

The results were inconsistent. Some trials showed benefits for pain or sleep, but the evidence was not uniform across studies. Cannabinoids were generally well-tolerated and safe during the study periods, though troublesome side effects occurred.

Why it matters

Chronic pain from rheumatic diseases affects millions of people, and current treatments are often inadequate. This review reveals a striking gap between patient interest in cannabinoids and the available scientific evidence. As of 2015, the evidence base consisted of fewer than 200 patients across just four trials.

The numbers in context

Four RCTs identified: 71 fibromyalgia patients, 30 spinal pain patients, 58 rheumatoid arthritis patients. Zero osteoarthritis RCTs. All trials were 2-5 weeks long. Three of four had high risk of bias. Pain refractory to conventional treatment was required in three studies.

How the study worked

Systematic search through April 2015 across CENTRAL, PubMed, cannabis-med.org, and clinicaltrials.gov. Included randomized controlled trials of at least 2 weeks duration with at least 10 patients per arm. Study quality was assessed using the Cochrane Risk of Bias Tool. Three of four studies had high risk of bias.

What this study cannot tell us

The tiny number of included trials severely limits the conclusions. All studies were very short (2-5 weeks), used different cannabinoid products and conditions, and three had high risk of bias. No herbal cannabis trials were identified.

How to read the evidence

Systematic review of RCTs with rigorous methodology, but the underlying evidence base consisted of very few, very small, high-bias trials.

When this study was published

Published in 2016 with search through April 2015. Additional trials may have been published since.

The bigger picture

The gap between public interest in cannabis for pain and the actual evidence base is enormous. This review underscores the urgent need for larger, longer, well-designed trials. The fact that researchers could only find four small, short trials for conditions affecting hundreds of millions of people globally reflects a significant research deficit.

Questions still open

Would longer trials with larger samples show clearer benefits? Why has so little rigorous research been conducted on cannabinoids for these common pain conditions? Would herbal cannabis or different THC:CBD ratios perform differently than the pharmaceutical products tested?

Common questions

Do cannabinoids work for arthritis pain?

As of this 2016 review, the evidence was too limited to say. Only four small, short trials existed across all rheumatic conditions, with inconsistent results.

Were there any positive findings?

Some trials showed benefits for pain and sleep, but results were not consistent across studies. Cannabinoids were generally well-tolerated during the short study periods.

Read the original research

Efficacy, tolerability and safety of cannabinoids in chronic pain associated with rheumatic diseases (fibromyalgia syndrome, back pain, osteoarthritis, rheumatoid arthritis): A systematic review of randomized controlled trials.

Schmerz (Berlin, Germany), 30(1), 47-61

View on PubMed ↗Publisher’s paper ↗

Citation

Fitzcharles, M-A; Baerwald, C; Ablin, J; Häuser, W. (2016). Efficacy, tolerability and safety of cannabinoids in chronic pain associated with rheumatic diseases (fibromyalgia syndrome, back pain, osteoarthritis, rheumatoid arthritis): A systematic review of randomized controlled trials.. Schmerz (Berlin, Germany), 30(1), 47-61. https://doi.org/10.1007/s00482-015-0084-3