Background/Purpose: Despite classic analgesic or effective treatments in rheumatic diseases, such as synthetic Disease Modifying Anti-Rheumatic Drugs in rheumatoid arthritis (RA), patients remain in pain and often turn to non-prescribed pharmacological alternatives, such as cannabis self-therapeutic use. However, this medical use of cannabis has not been thoroughly studied.

Methods:  We searched PubMed to find reports of interest published since 24 January 2020. The following search terms were used: “(cannabis OR cannabinol OR cannabinoids) and (rheumatoid OR osteoarthritis OR ankylosing OR arthritis OR arthralgia OR pain OR spondylitis)”. The incidence of cannabis consumption was calculated by metaproportion. Differences between cannabis users and non-users were expressed as standardized mean differences using the inverse-variance method. We also assessed the effects of cannabis on pain.

Results: A total of 2,807 citations were obtained from the initial search. After reading the title, abstract, and full text, we obtained 13 eligible studies, plus 7 found searching abstract databases, for a total of 13,134 patients with rheumatic diseases. Cannabis consumption. In the 12 studies on rheumatic diseases, a total of 2,666 patients reported cannabis consumption in a sample of 9,665 patients (incidence 40.3% [95%CI 26.2,55.2]), and 16% [95%CI 4.8,32.1] specified that they were currently taking cannabis. Cannabis use was higher in the three fibromyalgia studies (56.3% [95%CI 0.26,0.84], n=510) compared to five articles concerning RA or lupus (33.6% [95% CI 0.16,0.54], n=7,061). Effects of cannabis on pain over time. Cannabis consumption was associated with a decrease in pain intensity (VAS pain at baseline 8.2±2.9 vs. 5.6±3.5 mm over time; pooled effect size -1.75 [95%CI -2.75,-0.76]). Tolerance was good with mild or moderate side effects. Patients reported red eyes (7 to 90%), dry mouth (7 to 27%), hunger feeling (1 to 15%), sore thorat (10%), nausea (1 to 5%), somnolence (2 to 3%), hyperactivity (1 to 5%) or mood deflection (7%). Comparison of cannabis users and non-users. Cannabis users were younger (58.2±11.1 vs. 63.4±11.9 years; p< 0.001), more often smokers (OR 3.37 [95%CI 1.91,5.92]) or unemployed (OR 2.25 [95%CI 1.09,4.65]), and had higher pain intensity (4.9±2.4 vs. 4.1±2.5 mm; p< 0.001) than non-users. A significant relationship was found, with a three-fold risk of cannabis use among alcohol drinkers (148/304 (48.7%) vs. 382/1581 (24.2%); OR 3.12 [95% CI 2.41,4.04]). The proportion of cannabis users was significantly lower in female patients (OR 0.52 [95% CI 0.28,0.96], p=0.04).

Conclusion: Nearly 20% of patients suffering from rheumatic diseases actively consume cannabis, with an improvement in pain. The issue of cannabis use in the management of these patients should be addressed during medical consultation, essentially with cannabis-based standardized pharmaceutical products.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/cannabis-use-assessment-and-its-impact-on-pain-in-rheumatic-diseases-a-systematic-review-and-meta-analysis/