The journal of pain : official journal of the American Pain Society
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Review Meta Analysis
Inhaled cannabis for chronic neuropathic pain: an individual patient data meta-analysis.
Chronic neuropathic pain, the most frequent condition affecting the peripheral nervous system, remains underdiagnosed and difficult to treat. Inhaled cannabis may alleviate chronic neuropathic pain. Our objective was to synthesize the evidence on the use of inhaled cannabis for chronic neuropathic pain. We performed a systematic review and a meta-analysis of individual patient data. We registered our protocol with PROSPERO CRD42011001182. We searched in Cochrane Central, PubMed, EMBASE, and AMED. We considered all randomized controlled trials investigating chronic painful neuropathy and comparing inhaled cannabis with placebo. We pooled treatment effects following a hierarchical random-effects Bayesian responder model for the population-averaged subject-specific effect. Our evidence synthesis of individual patient data from 178 participants with 405 observed responses in 5 randomized controlled trials following patients for days to weeks provides evidence that inhaled cannabis results in short-term reductions in chronic neuropathic pain for 1 in every 5 to 6 patients treated (number needed to treat = 5.6 with a Bayesian 95% credible interval ranging between 3.4 and 14). Our inferences were insensitive to model assumptions, priors, and parameter choices. We caution that the small number of studies and participants, the short follow-up, shortcomings in allocation concealment, and considerable attrition limit the conclusions that can be drawn from the review. The Bayes factor is 332, corresponding to a posterior probability of effect of 99.7%. ⋯ This novel Bayesian meta-analysis of individual patient data from 5 randomized trials suggests that inhaled cannabis may provide short-term relief for 1 in 5 to 6 patients with neuropathic pain. Pragmatic trials are needed to evaluate the long-term benefits and risks of this treatment.
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Multicenter Study Controlled Clinical Trial
Cannabis for the Management of Pain: Assessment of Safety Study (COMPASS).
Cannabis is widely used as a self-management strategy by patients with a wide range of symptoms and diseases including chronic non-cancer pain. The safety of cannabis use for medical purposes has not been systematically evaluated. We conducted a prospective cohort study to describe safety issues among individuals with chronic non-cancer pain. A standardized herbal cannabis product (12.5% tetrahydrocannabinol) was dispensed to eligible individuals for a 1-year period; controls were individuals with chronic pain from the same clinics who were not cannabis users. The primary outcome consisted of serious adverse events and non-serious adverse events. Secondary safety outcomes included pulmonary and neurocognitive function and standard hematology, biochemistry, renal, liver, and endocrine function. Secondary efficacy parameters included pain and other symptoms, mood, and quality of life. Two hundred and fifteen individuals with chronic pain were recruited to the cannabis group (141 current users and 58 ex-users) and 216 controls (chronic pain but no current cannabis use) from 7 clinics across Canada. The median daily cannabis dose was 2.5 g/d. There was no difference in risk of serious adverse events (adjusted incidence rate ratio = 1.08, 95% confidence interval = .57-2.04) between groups. Medical cannabis users were at increased risk of non-serious adverse events (adjusted incidence rate ratio = 1.73, 95% confidence interval = 1.41-2.13); most were mild to moderate. There were no differences in secondary safety assessments. Quality-controlled herbal cannabis, when used by patients with experience of cannabis use as part of a monitored treatment program over 1 year, appears to have a reasonable safety profile. Longer-term monitoring for functional outcomes is needed. ⋯ This study evaluated the safety of cannabis use by patients with chronic pain over 1 year. The study found that there was a higher rate of adverse events among cannabis users compared with controls but not for serious adverse events at an average dose of 2.5 g herbal cannabis per day.
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Vulvodynia is a prevalent vulvovaginal pain condition that disrupts the sexual and psychological health of affected women and their partners. Cross-sectional and daily experience studies suggest that partner responses to this pain influence the psychological and sexual sequelae of affected couples. However, their daily impact on pain and anxiety remain unknown. Using a daily diary method, 69 women (M age = 28.12, SD = 6.68) diagnosed with vulvodynia and their cohabiting partners (M age = 29.67, SD = 8.10) reported on male partner responses to women's pain and anxiety symptoms on sexual intercourse days (M = 6.54, SD = 4.99) over 8 weeks. Women also reported their pain during intercourse. Results indicated that women reported greater pain on days when they perceived higher solicitous and negative male partner responses, and on days when their male partner reported greater solicitous and lower facilitative responses. Women indicated higher anxiety symptoms on days when they perceived more negative male partner responses; men's anxiety symptoms were greater on days when they reported higher negative male partner responses. Targeting partner responses may enhance the quality and efficacy of interventions aimed at reducing pain in women with vulvodynia and couples' psychological distress. ⋯ This article examines the daily associations among male partner responses, women's pain during intercourse, and anxiety in couples coping with vulvodynia. Targeting male partner responses may enhance the quality of interventions aimed at reducing women's pain and the psychological distress of couples coping with vulvodynia.
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Randomized Controlled Trial Comparative Study
Comparing counterconditioning and extinction as methods to the reduce fear of movement-related pain.
Cognitive-behavioral treatments for chronic pain typically target pain-related fear; exposure in vivo is a common treatment focusing on disconfirming harm expectancy of feared movements. Exposure therapy is tailored on Pavlovian extinction; an alternative fear reduction technique that also alters stimulus valence is counterconditioning. We compared both procedures to reduce pain-related fear using a voluntary joystick movement paradigm. Participants were randomly allocated to the counterconditioning or extinction group. During fear acquisition, moving the joystick in 2 directions (conditioned stimulus [CS+]) was followed by a painful electrocutaneous stimulus (pain-unconditioned stimulus [US]), whereas moving the joystick in 2 other directions was not (CS-). During fear reduction, 1 CS+ was extinguished, but another CS+ was still followed by pain in the extinction group; in the counterconditioning group, 1 CS+ was extinguished and followed by a monetary reward-US, and another CS+ was followed by both USs (pain-US and reward-US). The results indicate that counterconditioning effectively reduces pain-related fear but that it does not produce deeper fear reduction than extinction. Adding a reward-US to a painful movement attenuated neither fear nor the intensity/unpleasantness of the pain. Both procedures changed stimulus valence. We contend that changing the affective valence of feared movements might improve fear reduction and may prevent relapse. ⋯ This article reports no immediate differences between counterconditioning and extinction in reducing pain-related fear in the laboratory. Unexpectedly, both methods also altered stimulus valence. However, we cautiously suggest that methods explicitly focusing on altering the affective valence of feared movements may improve the long-term effectiveness of fear reduction and prevent relapse.
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Around 4 million children undergo inpatient surgery in the United States each year, however little is known about the impact of surgery and postoperative pain on children's health-related quality of life (HRQOL) during the weeks and months after surgery. We measured pain and HRQOL in a large, heterogeneous pediatric postsurgical population from baseline to 1-month follow-up. Over a 20-month period, parents of 915 children age 2 to 18 years (mean = 9.6 years), 50% male, 56% white, admitted to surgical services at a children's hospital enrolled in the study. Parent participants reported on sociodemographics, child HRQOL, and pain characteristics at baseline and 1 month after discharge. Although most of the children recovered to baseline by 1 month after hospital discharge, 23% of children had a significant decline in HRQOL. Logistic regression analyses found that increasing child age (odds ratio = 2.1 for age 13-18 years) and the presence of moderate-severe postsurgical pain at 1 month (odds ratio = 5.7) were significantly associated with deterioration in HRQOL from baseline to 1-month follow-up (P < .05 for each variable). Although HRQOL returns to the baseline level for most children, a sizeable proportion have significant deterioration in HRQOL associated with continued postsurgical pain at 1 month after hospital discharge from surgery. ⋯ This study addresses an important gap in the literature, examining pain and health-related quality of life in a broad population of children undergoing a wide range of inpatient surgeries. Evaluation of inpatient health services from a patient and family perspective is essential in evaluating outcomes of surgical care.