Retrospective Study of the Persistence in Medical Marijuana Use Among Certified Residents in the State of Florida

Introduction: Existing evidence on the persistence of medical marijuana (MMJ) use is limited. We evaluated the persistence of MMJ use among certified patients in Florida and its predictors thereof. Methods: For this retrospective cohort study, we used MMJ certification data linked to death certificates contained in the Medical Marijuana Outcomes Research Repository (MEMORY) from 2018 to 2023. Patients with a new MMJ certification, lasting a maximum of 210 days, were included and followed until the end of data availability. Temporary residents of Florida and those with < 450 days of follow-up were excluded. Patients were classified as non-persistent if they had no MMJ recertification within 30 days of expiration of the previous certification. Kaplan-Meier survival analysis was used to estimate MMJ persistence, censoring for death and loss to follow-up. Predictors were assessed using multivariable logistic regression by restricting the study cohort to patients with at least 2 years of follow-up. Results: A total of 796,676 new users of MMJ were identified with a mean age of 47.2 + 16.7 years, of whom 53.4% were male. Post-traumatic stress disorder (PTSD), inclusive of conditions of a similar kind or class (54%) and chronic non-malignant pain (30%) were the most common qualifying conditions. 66% of newly certified patients were recertified within 30 days and met our persistence criterion, gradually reducing to 21.5% at 2 years. In the multivariable logistic regression, two-year persistence varied significantly by gender (female vs male OR [95% CI]: 0.92 [0.91, 0.93]), age group (0-12 years vs 18-64 years OR 0.65 [0.53, 0.79] and > 65 years vs 18-64 years, OR 0.96 [0.95, 0.98] respectively), qualifying conditions, route of administration and regular versus low THC cannabis. Conclusion: Less than one quarter of newly certified MMJ users continued use at two years, with a lower persistence among the age extremes, females and those with certain conditions. Future research should investigate whether discontinuation of MMJ is related to a lack of effectiveness, safety concerns or other reasons.