A Longitudinal Assessment of Endometriosis Patients Prescribed Cannabis-Based Medicinal Products: A Case Series From the UK Medical Cannabis Registry.

BACKGROUND: Although there is growing evidence supporting the use of cannabis-based medicinal products (CBMPs) for the management of chronic pain, there is a paucity of data on their effect on endometriosis-associated chronic pain.

AIMS: This study aimed to perform an analysis of pain-specific and general health-related quality of life (HRQoL) outcomes for patients with endometriosis-associated chronic pain treated with CBMPs.

MATERIALS AND METHODS: Primary outcomes included changes in patient-reported outcome measures (PrOMs) from baseline to 1, 3, 6, 12 and 18 months. A repeated measures ANOVA was applied to assess changes in PrOMs at 1 to 18 months from baseline. Secondary outcomes included incidence and frequency of adverse events (AEs).

RESULTS: Sixty-three patients met inclusion criteria. Initiation of CBMPs was associated with improvements in all pain-specific PrOMs from baseline to 18 months (p < 0.050). EQ-5D-5L index value showed improvements between baseline and all months (p < 0.050). Anxiety and sleep quality PrOMs showed improvements from baseline to 18 months (p < 0.050). Minimal clinically significant differences (11%-37%), moderately important improvements (5%-22%) and substantial improvements (0%-11%) were observed in the Brief Pain Inventory (BPI) and pain severity visual analogue scale. Sixty-two adverse events were reported by 16 (25.40%) participants.

CONCLUSIONS: This study observed an association between CBMP treatment and improvements in pain and HRQoL in patients with endometriosis. Causality cannot be inferred due to the nature of this observational study; however, these findings provide complementary evidence for the development of randomised controlled trials to assess the efficacy of CBMPs for endometriosis-associated chronic pain.