REVIEW OF: Safakish R et al, Pain Medicine 2020 Jun 18;pnaa163. Epub ahead of print.

Although chronic pain affects 10%–30% of the adult population and contributes to a host of physical and mental health problems, we often find ourselves with limited options to assist the patient with pain in front of us. While medical cannabis (MJ) has shown promise as a potential treatment option in smaller trials, the authors of the current study hoped to replicate the results in a larger population.

In this open-label, observational, longitudinal study, researchers recruited adults over 25 years old with chronic pain (defined as pain for over 3 months) at a cannabis clinic in Toronto, ­Canada. The authors followed these patients for 12 months and monitored their pain severity (via the Brief Pain Inventory [BPI], a 0–10 scale), the pain’s interference with quality of life (via the Short Form Health Survey [SFHS], a 0–100 scale), physical symptoms, and use of opioids. Prescribers personalized dosing and route using an average daily dose of 1.25–1.5 grams of dry cannabis flowers (approximately 3 joints).

Although 1,245 subjects initially signed up for the study, only 60% (n = 751) kept at least 1 follow-up appointment (and were analyzed), and just 3% (n = 43) attended the final 12-month follow-up. The mean age of participants was 49.6 years, and 43% were men. About half of the subjects reported one pain condition (47%), while the rest had multiple pain issues. The most commonly reported pain conditions were back pain (47%), osteoarthritis (28%), chronic headaches (21%), fibromyalgia (18%), and degenerative disc disease (16%).

At each follow-up appointment, patients reported significant improvement in pain severity (mean BPI score dropped from 5.58 at baseline to 3.49 at month 12, p < 0.001) and life interference (6.23 at baseline to 3.54 at month 12, p = 0.001) with continued MJ. The effect size was 0.30, which is considered medium.

Those who followed up in the study had reduced anxiety, fatigue, nausea, and headaches over a period of 12 months, and no major adverse events were reported. The authors found statistically significant improvement in physical and mental health–related quality of life measures on the SFHS (p < 0.05), but the change in the physical health–related index does not appear to be clinically meaningful (scores improved from 31+/-8 to 33+/-11).

Patients taking opioids at baseline reported a reduction in their opioid dosage over time; however, the sample size was too small to generalize results (from 84 at baseline to 4 at month 12).

CATR’S TAKE
In patients with chronic pain, medical cannabis may be associated with reduced pain, improved physical and emotional well-being, and even reduced opioid usage. However, given the lack of a control group and the high attrition rate in this study, we would like to see these results replicated in a larger, randomized controlled trial.