While humans have recognised the medicinal value of cannabis for thousands of years, a long period of prohibition which coincided with the most significant period of scientific and medical development in our history has left a prominent gap in our knowledge of the plant. This lack of scientific knowledge and clinical evidence has led to the current situation we see in the UK, and other countries around the world, where medical cannabis has been legalised, yet prescriptions remain limited.
On the 1st of November 2018, the UK government rescheduled cannabis in the Misuse of Drugs Act 1971, effectively legalising the medical use of the drug. While, in theory, this allowed doctors to prescribe cannabis-based medicines this was only possible under a small number of circumstances.
Even now, two and a half years after legalisation, medical cannabis can only be prescribed by specialist clinicians – and even then, this is usually only considered as a last resort when other treatment options have failed. The number one factor which is stalling the wider roll-out of medical cannabis in the UK is a lack of clinical and real-world evidence. To counteract this, Sapphire Medical Clinics developed the UK Medical Cannabis Registry.
The UK Medical Cannabis Registry
This patient registry is the first of its kind launched to capture prospective data from patients that have been treated with medical cannabis products produced to Good Manufacturing Practice criteria. The UK Medical Cannabis Registry was set up in December 2019 to investigate prescribed formulations, adverse events, and patient-reported outcome measures.
On enrolment into the registry, UK patients who had been prescribed medical cannabis products for a range of indications agreed to provide patient-reported outcome measures (PROMs) through an online platform at baseline (enrolment) and at 1 month, 3 months, 6 months, and then 6 monthly intervals thereafter. The aim of the study is to collect and analyse clinical data that may be used to progress our understanding of medical cannabis in the UK.
Recently, the first results on the outcomes of the registry from 129 medical cannabis patients were published. For this analysis, data was extracted for patients who were prescribed medical cannabis and had recorded PROMs at 1 and/or 3 months from baseline.
Analysing Patient-Recorded Data
A total of three quality-of-life PROMs were completed by all patients included in this analysis: EQ-5D-5L (a tool that measures quality of life across several domains in addition to a visual scale for general health), General Anxiety Disorder-7 (GAD-7), and Single-Item Sleep Quality Scale (SQS).
The researchers also analysed demographic variables, conditions, tobacco and alcohol use, cannabis status, medication, and adverse events using descriptive analysis.
Findings from Preliminary Results
Of the 210 patients who had been so far registered on the UK Medical Cannabis Registry, 129 had completed baseline PROMs. Of these, 70 patients had completed PROMs at 1 month and 50 patients had recorded PROMs at 3 months.
The most common primary diagnosis was chronic pain (37.2%; n=48), followed by neuropathic pain (17.1%; n=22) and anxiety (8.5%; n=11). The incidence of hypertension (n = 9; 7.0%), depression and/or anxiety (n = 39; 30.2%), arthritis (n = 22; 17.1%); epilepsy (n = 5; 3.9%); endocrine dysfunction (n = 4; 3.1%) was also recorded.
The median number of cannabis-based medical products (CBMPs) at the initiation of therapy was 2, with 33 (25.6%), 86 (66.7%), 8 (6.2%), and 2 (1.6%) being prescribed 1 to 4 different CBMPs, respectively. Prescribed CBMPs included oil preparations, and vaporised fry flower (flowers or granulate). The median initial CBD dose was 20.0 mg (Range: 0.0-768.0 mg). The median initial THC dose was 3.9 mg (Range: 0.0-660.0 mg).
The data collected through PROMs revealed statistically significant improvements in health-related quality of life at 1 month and 3 months in GAD-7, SQS, E5-5D-5L pain and discomfort, and anxiety and depression subscales, as well as EQ-VAS scores, and EQ-5D-5L index values. Statistically significant improvements were demonstrated at 3 months only in the EQ-5D-5L usual activities subscale.
The collected data presented a total of 31 adverse events, the most common of which were somnolence and constipation (each experienced by 4 patients).
Discussion and Conclusions
The initial data collected from patients on the UK Medical Cannabis Registry suggest that medical cannabis may be associated with improved health-related quality of life across several conditions. There was a particularly significant improvement in symptoms of anxiety and depression, sleep quality, pain, and discomfort. However, the researchers involved in this study warn that these findings should be treated with caution, given the limited scope of the available data.
Nevertheless, these preliminary findings are consistent results from an audit of 400 patients prescribed CBD oil in New Zealand, which found a mean increase health-related quality of life. The findings on improved anxiety symptoms are also supported by a number of other studies that have implied the potential benefit of CBMPs in anxiety symptoms and therefore anxiety disorders. This does, however, also require further investigation.
While this analysis demonstrated a general improvement in PROMs, the researchers note that the current study is likely limited by the heterogeneity of the studied population which provided outcomes for all conditions where CBMPs have been prescribed. The analysis concludes that subsequent studies of the UK Medical Cannabis Registry will aim to undertake a disease-specific approach to analyse short and long-term outcomes.
Overall, the results of this initial analysis suggest that CBMPs may be associated with a modest, yet clinically significant improvement in health-related quality of life across a broad spectrum of chronic diseases, as reported at 1 month and 3 months follow-up.