Measuring the Change in Health-Related Quality of Life in Patients Using Marijuana for Pain Relief

Abstract
Introduction: Current evidence suggests that cannabinoids are safe with minimal side effects and are effective in managing chronic pain. Data also show that medical marijuana (MM) may improve quality of life (QoL) among patients. However, there are little data showing the health-related QoL (HRQoL) benefit in MM patients using it for pain. The purpose of this study was to determine if there is a relationship between HRQol and MM use in patients using it to relieve pain. Methods: All pain patients aged 18 years or older enrolled in the Pennsylvania MM program were eligible for inclusion. Recruited subjects completed 4 surveys – at enrollment (baseline) then 2, 4, and 8 weeks post-enrollment. We used the EQ-5D survey tool for measuring HRQoL. The primary outcome measure was the change in the EQ-5D Index Score from survey 2 to survey 4 (6 week difference). Secondary outcomes included self-reported pain and health scores. Data were analyzed using a paired t test and repeated-measures multivariable analysis to control for both gender and length of time between surveys. Results: 1,762 people responded to the screening request, and 1,393 (79%) met screening criteria. Of those, 353 (25.3%) agreed to participate and 51% completed all 4 surveys, for a final sample of 181 with 85 male and 95 female and one nonbinary subject. The average age was 41.21 (SD = 12.9) years, with no difference between genders. The adjusted HRQoL score improved from 0.722 to 0.747 (p = 0.011) from survey 2 to survey 4, as did the self-reported pain and health scores. The EQ-5D subscales revealed no change in mobility or usual activities, significant improvement in anxiety and pain, and a significant worsening in self-care. Conclusion: The results show a significant improvement in HRQoL among patients using MM for pain. The EQ-5D subscales validated the pain improvement and also showed an improvement in anxiety. However, the decline in the self-care subscale may have tempered the overall improvement in HRQoL, and further research into which aspects of self-care are impacted by MM use in this population is warranted. Overall, there is a positive relationship between MM use and HRQoL in patients using it for pain.