Cannabidiol (CBD) is increasingly used as analgesic medication even though the recent International Association for the Study of Pain presidential task force on cannabis and cannabinoid analgesia found a lack of trials examining CBD for pain management. The present trial examines CBD as add on analgesic therapy in patients with hand osteoarthritis or psoriatic arthritis experiencing moderate pain intensity despite therapy. Using a randomized double-blind, placebo-controlled design, patients received synthetic CBD 20-30mg or placebo daily for 12 weeks. Primary outcome was pain intensity during the last 24 hours (0-100mm); safety outcomes were percentage of patients experiencing adverse events and a characterization of serious adverse events. Explorative outcomes included change in Pittsburgh Sleep Quality Index (PSQI), Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale (PCS) and Health Assessment Questionnaire (HAQ-DI).One hundred and thirty-six patients were randomized 129 were included in the primary analysis. Between group difference in pain intensity at 12 weeks was 0.23mm (95%CI -9.41 to 9.90; p = 0.96). 22% patients receiving CBD and 21% receiving placebo experienced a reduction in pain intensity of more than 30mm. We found neither clinically nor statistically significant effect of CBD for pain intensity in patients with hand osteoarthritis and psoriatic arthritis when compared to placebo. Additionally, no statistically significant effects were found on sleep quality, depression, anxiety, or pain catastrophizing scores.
Pain phenotyping: Participants will answer a series of questionnaires related to the pain experience to assess: Anxiety and depression (the hospital anxiety and depression scale), pain catastrophizing (the pain catastrophizing scale), pain description (The short form McGill questionnaire and pain detect questionnaire), sleep quality (Pittsburgh sleep quality index) and a Widespread Pain Assessment questionnaire and the Symptom Severity Index. To assess function and quality of life the Short form 36 and Health assessment questionnaire will be used.
Patients with PsA: Will receive an examination for disease specific tests including: joint tenderness and swelling using the EULAR66/68 regiment, dactylitis evaluation using Leeds dactylitis index basic, skin involvement using the psoriasis area and severity index and nail psoriasis via nail psoriasis severity index.
Examination programme: All participants will receive a full medical interview and a physical examination which includes auscultation, blood pressure, heart rate and saturation measurements and BMI calculation. All participants will have blood drawn for later examination for markers of inflammation and degeneration. All participants will go through Quantitative Sensory Testing (QST). QST covers a wide range of different examinations techniques used to assess the functional status of the somatosensory system. In the present study pressure algometry and cuff algometry will be performed.
Patients with Hand-OA: Will receive the following disease specific examinations evaluation of tender and swollen joints of the hands and wrists. Grip and pinch strength measurements using a hand-held dynamometer and the functional index of hand-osteoarthritis.
Patients will be asked for adverse events at each visit and these are recorded in the eCRF.
Primary outcome: Changes in VAS pain during the last 24 hours from baseline to 12 weeks. Measured with a 100mm VAS from the most symptomatic hand (Hand-OA) or joint (PsA).
The trial consists of a screening visit, a baseline visit where the patient will undergo randomization, a phone consultation after 4 weeks a blood and urin sample after 6 weeks. and an end of trial visit at week 12. Patients will be invited to a follow-up visit at week 24.