Patients' Health-Related Quality of Life and Use of Medicinal Cannabis: A Cross-Sectional Survey Study

Background Studies on medicinal cannabis (MC) have primarily investigated effects on diseases and symptoms, while there is only sparse knowledge on patients' health-related quality of life. Our aim was, firstly, to compare the health-related quality of life of patients (MC users and non-users) within four specified diagnostic indications (multiple sclerosis, paraplegia, neuropathy, and nausea and vomiting after chemotherapy) with that of patients with other diagnostic indications (MC users only) and the adult population (non-users only). Secondly, we estimate the associations between use of MC and health-related quality of life for patients in the four specified diagnostic indications. Methods We collected data on quality-adjusted life years (QALYs), using EQ-5D-3L, and patients' self-reported use of MC in a Danish nationwide online survey distributed to 23,846 patients in October 2020. We compared QALY scores of all groups using a two-tailed t-test, listed QALY scores of MC users versus non-users, and investigated associations between QALY score and MC use using unadjusted and adjusted linear regression analyses. Significance level was set to p-value < 0.05. Results A total of 9265 patients took part in the survey. All diagnostic indications had a statistically significant lower QALY score than the adult population (0.87). Paraplegia patients had the lowest QALY score, being 0.36 lower, followed by other diagnostic indication (- 0.34), multiple sclerosis (- 0.20), neuropathy (- 0.13), and nausea and vomiting after chemotherapy (- 0.06). MC users had a statistically significant lower QALY score than non-users (0.44 vs 0.74). Users redeeming 1-6 and >= 7 MC prescriptions (except for paraplegia patients) had a statistically significant lower QALY score than non-users, ranging between 0.11-0.24 and 0.26-0.32 lower than non-users, accordingly. Although, it should be noted that the number of users was small when stratifying by number of prescriptions. Conclusion Patients with either multiple sclerosis, paraplegia, neuropathy, or nausea and vomiting after chemotherapy had a significantly lower health-related quality of life than individuals from the adult population. Users of medicinal cannabis also had a significantly lower health-related quality of life compared with non-users, in all diagnostic indications.