This 10-year single-arm observational study followed 1,000 cannabis-naïve adults with chronic low back pain (CLBP) who were already on long-term opioids, evaluating medical cannabis therapy's effects on opioid use (MMEQ), pain (NRS), functional disability (ODI), polypharmacy, and adverse events from 2015 to 2024.
Among 638 completers (63.8%), opioid use fell 89.8% (62.8 → 6.4 mg MMEQ/day), pain scores fell 84.2% (NRS 8.71 → 1.37), and ODI improved by 16.1 points (52.9% → 36.8%); MCID responder rates were 91.2% (opioid reduction), 96.6% (pain), and 62.1% (disability); serious psychiatric events occurred in only 0.02% of visits.
No control group means regression to the mean, placebo effects, and natural history cannot be separated from treatment effects — a recent phase 3 RCT showed only a −0.6 NRS difference vs. placebo, far below this study's −7.34 points. The 36.2% dropout rate likely enriched completers with 'super-responders,' inflating effect sizes. Single-center, tertiary-referral design limits generalizability to primary care populations.
These findings are hypothesis-generating only and should not change prescribing practice on their own; the effect sizes far exceed placebo-controlled RCT benchmarks, pointing to major observational bias. Clinicians should await adequately powered RCTs before routinely offering medical cannabis as an opioid-sparing strategy for CLBP.
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