Influence of Cannabinoid Treatment on Trajectories of Patient-Related Outcomes in Chronic Pain: Pain Intensity, Emotional Distress, Tolerability and Physical Disability.

The treatment of chronic pain with cannabinoids is becoming more widespread and popular among patients. However, studies show that only a few patients experience any benefit from this treatment. It also remains unclear which domains are affected by cannabinoid treatment. Therefore, the present study is novel in that it explores the effects of cannabinoid treatment on four patient-related outcome measures (PROMs), and includes patients with chronic refractory pain conditions who have been given the option of cannabinoid treatment. A retrospective design was used to evaluate the impact of cannabinoid treatment on patients with refractory pain in two German outpatient pain clinics. The present study shows that pain intensity (mean relative reduction (-14.9 ± 22.6%), emotional distress (-9.2 ± 43.5%), pain-associated disability (-7.0 ± 46.5%) and tolerability of pain (-11 ± 23.4%)) improved with cannabinoid treatment. Interestingly, the trajectories of the PROMs seemed to differ between patients, with only 30% of patients responding with respect to pain intensity, but showing improvements in other PROMs. Although the mean treatment effects remained limited, the cumulative magnitude of change in all dimensions may affect patients' quality of life. In summary, a singular evaluation with pain intensity as the sole outcome does not cover the multidimensional effects of cannabinoids. Therefore, the treatment effects of cannabinoids should be evaluated with different PROMs.