Medicinal cannabis and its impact on patient-reported outcomes in chronic health

In a recent study published in PLOS ONE, researchers evaluated health-related quality of life (HRQL) and other outcomes in patients taking medicinal cannabis (MC).

Around 47% of Australians have chronic health conditions, with one in five persons experiencing persistent chronic pain, negatively affecting their HRQL. Australian legislative changes in 2016 allowed patients unresponsive to conventional therapy to access medicinal cannabis prescribed by clinicians. It is necessary to consider patient-reported outcomes (PROs) in the assessment and management of chronic conditions.

HRQL is a multidimensional construct about perceptions of the impact of a disease or treatment on cognitive, social, emotional, and physical functions. PROs are considered the gold standard for pain assessment and are evaluated with PRO measures (PROMs).

There is limited data on how medical cannabis affects HRQL; therefore, real-world evidence is required to investigate the changes in HRQL with medical cannabis usage and inform policy-making and regulation.

About the study

In the present study, researchers presented interim findings from the quality-of-life evaluation study (QUEST) initiative assessing PROs such as pain, fatigue, HRQL, anxiety, depression, and sleep disturbance in Australian patients taking medical cannabis.

Eligible patients were 18 or older, had medical cannabis oil products prescribed by a clinician, had not accessed medical cannabis within the past four weeks, and could read/complete PROMs.

Medical cannabis oil products were phytocannabinoids (cannabidiol and delta-9-tetrahydrocannabinol) in a medium-chain triglyceride carrier oil. Data on patient demographics, clinical characteristics, medical cannabis prescriptions, and health conditions treated with medical cannabis were collected.

PROMs were administered pre-MC treatment (baseline), two weeks post-treatment commencement, and monthly for three months.

PROMs had to be completed within seven days of the time point, beyond which it was treated as a missed assessment. Patients completed the EuroQol group’s EQ-5D-5L health status questionnaire, depression anxiety stress scale (DASS-21), the European Organization for Research and Treatment of Cancer (EORTC) core quality of life questionnaire (QLQ-C30), and PRO measurement information system (PROMIS) short forms in sleep disturbance and fatigue.

The team calculated means, standard deviations, and effect sizes for each time point. Linear regression was used on QLQ-C30 scores to assess baseline differences in patient characteristics. Linear mixed models examined the change(s) in PRO scores over time. Changes in DASS severity categories over time were analyzed using the chi-squared test.

Findings

In total, 2,762 eligible patients completed baseline PROMs; of these, 2,327 patients completed at least one follow-up assessment and were analyzed. Participants were aged 18-97, and 62.8% were females. Over 25% were unemployed, on limited work duties, or on leave due to illness. Some participants were previously prescribed medical cannabis but not in the four weeks before participation. 22.4% of participants used recreational cannabis or medical cannabis without a prescription within the past year.

Around half of the participants were prescribed medical cannabis for multiple health conditions. Most patients (68.7%) were prescribed medical cannabis for chronic pain, followed by insomnia (22.9%), anxiety (21.5%), and mixed depression and anxiety (11.0%). EQ-5D-5L index and QLQ-C30 summary scores showed significant improvement trends.

The average QLQ-C30 summary and EQ-5D-5L index scores increased by 10.7 and 0.15 points from baseline to mean follow-up, respectively, implying a clinically meaningful improvement. Similarly, QLQ-C30 pain scores displayed significant improvement trends, increasing by 16.51 points from baseline to mean follow-up, indicative of clinically meaningful change. There was no evidence of changes in sleep disturbance.

Improvements in fatigue were also clinically meaningful. The average DASS-anxiety and -depression scores showed significant improvement trends over time. However, the mean scores did not reach the recommended five-point threshold. The chi-squared test revealed a significant improvement from more severe categories towards the normal range.

Conclusions

The researchers observed an improvement in HRQL over three months among Australian patients taking medical cannabis. Results indicate statistically significant and clinically meaningful improvements in HRQL and fatigue.

Similar improvements in pain, depression, and anxiety scores were evident in patients with chronic pain, depression, and anxiety, respectively. Notably, no improvements were observed for sleep disturbance. 

Taken together, the findings suggest that medical cannabis may alleviate pain, anxiety, depression, and fatigue and improve HRQL in patients with chronic health conditions. Sleep outcomes did not improve or worsen.

Thus, further research is required to analyze the effects of medical cannabis on sleep-related conditions. The researchers indicated that the follow-up would continue until 12 months to investigate whether improvements last over the long term. 

Written by

Tarun Sai Lomte

Tarun is a writer based in Hyderabad, India. He has a Master’s degree in Biotechnology from the University of Hyderabad and is enthusiastic about scientific research. He enjoys reading research papers and literature reviews and is passionate about writing.