Systematic Review of the Costs and Benefits of Prescribed Cannabis-Based Medicines for the Management of Chronic Illness: Lessons from Multiple Sclerosis.

Introduction: Cannabis-based medicines (CBMs) may offer relief from symptoms of disease; however, their additional cost needs to be considered alongside their effectiveness. We sought to review the economic costs and benefits of prescribed CBMs in any chronic illness, and the frameworks used for their economic evaluation. Methods: A systematic review of eight medical and economic databases, from inception to mid-December 2016, was undertaken. MeSH headings and text words relating to economic costs and benefits, and CBMs were combined. Study quality was assessed using relevant checklists and results were synthesised in narrative form. Results: Of 2514 identified records, ten studies met the eligibility criteria, all for the management of multiple sclerosis (MS). Six contained economic evaluations, four studies reported utility-based quality of life, and one was a willingness-to-pay study. Four of five industry-sponsored cost-utility analyses for MS spasticity reported nabiximols as being cost-effective from a European health system perspective. Incremental cost-effectiveness ratios per quality-adjusted life-year (QALY) gained for these five studies were pound49,257 (UK); pound10,891 (Wales); euro11,214 (Germany); euro4968 (Italy); and dominant (Spain). Nabiximols for the management of MS spasticity was not associated with statistically significant improvements in EQ-5D scores compared with standard care. Study quality was moderate overall, with limited inclusion of both relevant societal costs and discussions of potential bias. Conclusions: Prescribed CBMs are a potentially cost-effective add-on treatment for MS spasticity; however, this evidence is uncertain. Further investment in randomised trials with in-built economic evaluations is warranted for a wider range of clinical indications. Systematic Review Registration: PROSPERO Registration Number: CRD42014006370.