A study published recently in the journal Biomedicines found that inhaled medical cannabis was associated with sustained improvements in pain and disability over five years among patients with treatment-resistant chronic low back pain.
The study was conducted by researchers from the Department of Orthopedics at Hasharon Hospital, Rabin Medical Center in Israel.
Researchers analyzed data from 241 adults with chronic low back pain who had failed at least one year of conventional treatments, including opioids, NSAIDs, physiotherapy and, in many cases, antidepressants and anticonvulsants. Patients were then treated with inhaled medical cannabis, primarily smoked cannabis, with THC levels ranging from 4% to 22% and CBD levels ranging from 2% to 22%.
After five years, 238 of the 241 patients provided follow-up data, and 224 remained on active medical cannabis treatment.
Researchers found large and sustained improvements across multiple pain and disability measures. Average pain scores fell from 8.08 before cannabis treatment to 2.72 after five years. Patients also saw improvements in disability, pain severity and pain interference.
At year five, 89.2% of patients achieved at least a 30% reduction in pain, while 77.2% achieved at least a 50% reduction. In addition, 93.4% met the minimum clinically important difference for pain reduction.
The study also found a sharp decline in the use of other medications. Opioid use dropped from 100% of patients at baseline to 4.6% after five years. NSAID use fell from 100% to 7.1%, SSRI/SNRI use declined from 80.5% to 5.4%, and gabapentinoid use fell from 38.6% to 2.5%.
Researchers reported that only five patients, or 2.1%, discontinued cannabis due to adverse events or lack of effectiveness. Across 1,205 patient-years of cannabis exposure, adverse events were overwhelmingly mild, with ocular, cognitive and gastrointestinal effects being the most common.
The study’s authors emphasized that the findings are observational and do not prove that cannabis caused the improvements. Because there was no randomized control group, they said the results could have been influenced by factors such as regression to the mean, patient expectations, self-selection and other changes over time.
Still, researchers concluded that the findings support consideration of inhaled medical cannabis as a potentially meaningful opioid-sparing option for patients with chronic low back pain who have failed conventional multimodal therapy, while calling for randomized comparative trials to confirm the results.
