Placebo response in neuropathic pain after spinal cord injury: a meta-analysis of individual participant data.

BACKGROUND: Understanding factors associated with high placebo responses in clinical trials increases the likelihood of detecting a meaningful treatment effect. The aim of the present study was to identify subject-level factors that contribute to placebo variability in patients with neuropathic pain due to spinal cord injury (SCI). METHODS: Multiple regression analysis of patient data from randomized, double-blind, placebo-controlled trials (duration >4 weeks) involving individuals with SCI was performed. Patient demographics, as well as injury and pain characteristics were examined for their association with changes in pain rating from baseline to the end of the trial (i.e., placebo response). The overall effect of individual predictors was quantified with meta-analysis statistics. RESULTS: A total of 276 patients with SCI from six studies were included in the analysis. Based on the meta-analysis of subject-level predictors, larger placebo responses were associated with male subjects (ß=0.635; standard error [SE]=0.262; p=0.016) and higher baseline pain (ß=-0.146; SE=0.073; p=0.044). There were no significant effects for injury characteristics (i.e., severity, level, and time since injury) or pain characteristics (i.e., location and evoked). No significant publication bias was detected. CONCLUSION: The current meta-analysis of individual patient data demonstrated the importance of sex and baseline pain intensity on changes in pain ratings in the placebo arm of SCI central neuropathic pain randomized controlled clinical trials. Overall, our findings indicate that placebo responses occur independent of injury characteristics.

Cannabis use in persons with traumatic spinal cord injury in Denmark.

OBJECTIVE: To evaluate recreational and medical cannabis use in individuals with traumatic spinal cord injury, including reasons and predictors for use, perceived benefits and negative consequences. DESIGN: Cross-sectional survey in Denmark. METHODS: A 35-item questionnaire was sent to 1,101 patients with spinal cord injury who had been in contact with a rehabilitation centre between 1990 and 2012. RESULTS: A total of 537 participants completed the questionnaire. Of these, 36% had tried cannabis at least once and 9% were current users. Of current users, 79% had started to use cannabis before their spinal cord injury. The main reason for use was pleasure, but 65% used cannabis partly for spinal cord injury-related consequences and 59% reported at least good effect on pain and spasticity. Negative consequences of use were primarily inertia and feeling quiet/subdued. Lower age, living in rural areas/larger cities, tobacco-smoking, high alcohol intake and higher muscle stiffness were significantly associated with cannabis use. Those who had never tried cannabis reported that they would mainly use cannabis to alleviate pain and spasticity if it were legalized. CONCLUSION: Cannabis use is more frequent among individuals with spinal cord injury in Denmark than among the general population. High muscle stiffness and various demographic characteristics (lower age, living in rural areas/larger cities, tobacco-smoking and high alcohol intake) were associated with cannabis use. Most participants had started using cannabis before their spinal cord injury. There was considerable overlap between recreational and disability-related use.

Ultramicronized palmitoylethanolamide in spinal cord injury neuropathic pain: a randomized, double-blind, placebo-controlled trial.

Neuropathic pain and spasticity after spinal cord injury (SCI) represent significant problems. Palmitoylethanolamide (PEA), a fatty acid amide that is produced in many cells in the body, is thought to potentiate the action of endocannabinoids and to reduce pain and inflammation. This randomized, double-blind, placebo-controlled, parallel multicenter study was performed to investigate the effect of ultramicronized PEA (PEA-um) as add-on therapy on neuropathic pain in individuals with SCI. A pain diary was completed and questionnaires were completed before and after the 12-week treatment with either placebo or PEA-um. The primary outcome measure was the change in mean neuropathic pain intensity from the 1-week baseline period to the last week of treatment measured on a numeric rating scale ranging from 0 to 10. The primary efficacy analysis was the intention to treat (baseline observation carried forward). Secondary outcomes included a per protocol analysis and effects on spasticity, evoked pain, sleep problems, anxiety, depression, and global impression of change. We randomized 73 individuals with neuropathic pain due to SCI, of which 5 had a major protocol violation, and thus 68 were included in the primary analysis. There was no difference in mean pain intensity between PEA-um and placebo treatment (P = 0.46, mean reductions in pain scores 0.4 (-0.1 to 0.9) vs 0.7 (0.2-1.2); difference of means 0.3 (-0.4 to 0.9)). There was also no effect of PEA-um as add-on therapy on spasticity, insomnia, or psychological functioning. PEA was not associated with more adverse effects than placebo.

Persistent Pain and Sensory Abnormalities after Abdominoplasty.

BACKGROUND: Persistent postsurgical pain is a well-recognized problem after a number of common surgical procedures, such as amputation, thoracotomy, and inguinal hernia repair. Less is known about persistent pain after cosmetic surgical procedures. We, therefore, decided to study the incidence and characteristics of persistent pain after abdominoplasty, which is one of the most frequent cosmetic surgical procedures. METHODS: In September 2014, a link to a web-based questionnaire was mailed to 217 patients who had undergone abdominoplasty between 2006 and 2014 at the Department of Plastic Surgery, Aalborg University Hospital, Denmark. The questionnaire included questions about pain and sensory abnormalities located to the abdominal skin, and physical and psychological function; patient satisfaction with surgery was rated on a 4-point scale. RESULTS: One hundred seventy patients answered the questionnaire. Fourteen patients (8.2%) reported pain within the past 7 days related to the abdominoplasty. Abnormal abdominal skin sensation was common and reported by 138 patients (81%). Sensory hypersensitivity was associated with the presence of persistent pain. Satisfaction with the procedure was reported by 149 (88%) patients. The majority of patients reported improvement on all physical and psychological factors. Patients with pain were more often disappointed with the surgery and unwilling to recommend the surgery. CONCLUSIONS: Overall, patients were satisfied with the procedure, although abnormal abdominal skin sensation was common. However, there is a risk of developing persistent neuropathic pain after abdominoplasty, and patients should be informed about this before surgery.