The journal of pain : official journal of the American Pain Society
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Multicenter Study Observational Study
Long-Term Outcome of the Management of Chronic Neuropathic Pain: A Prospective Observational Study.
This prospective observational cohort study addressed the long-term clinical effectiveness of the management of chronic neuropathic noncancer pain at 7 Canadian tertiary pain centers. Patients were treated according to standard guidelines and were followed at 3, 6, 12, 18, and 24 months. Standard outcome measures for pain, mood, quality of life, and overall treatment satisfaction were administered, with the primary outcome measure designated as the composite of 30% reduction in average pain intensity and 1-point decrease in the mean Interference Scale Score (0-10) of the Brief Pain Inventory at 12 months relative to baseline. ⋯ Opioid therapy may not be beneficial for the long term. Perspective: Evidence-based treatment of chronic neuropathic pain provides long-term benefit in only about one-quarter of patients seen in tertiary care centers. Opioid therapy may not be beneficial.
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Randomized Controlled Trial Multicenter Study
The Contribution of Differential Opioid Responsiveness to Identification of Opioid Risk in Chronic Pain Patients.
The Screener and Opioid Assessment for Patients with Pain-Revised (SOAPP-R) predicts increased risk of opioid misuse in chronic pain patients. We evaluated whether higher SOAPP-R scores are associated with greater opioid reinforcing properties, potentially contributing to their predictive utility. Across 2 counterbalanced laboratory sessions, 55 chronic low back pain sufferers completed the SOAPP-R at baseline and measures of back pain intensity, evoked pain responsiveness (thermal, ischemic), and subjective opioid effects after receiving intravenous morphine (.08 mg/kg) or saline placebo. Morphine effect measures were derived for all outcomes, reflecting the difference between morphine and placebo condition values. Higher SOAPP-R scores were significantly associated with greater desire to take morphine again, less feeling down and feeling bad, and greater reductions in sensory low back pain intensity following morphine administration. This latter effect was due primarily to SOAPP-R content assessing medication-specific attitudes and behavior. Individuals exceeding the clinical cutoff (18 or higher) on the SOAPP-R exhibited significantly greater morphine liking, desire to take morphine again, and feeling sedated; less feeling bad; and greater reductions in sensory low back pain following morphine. The SOAPP-R may predict elevated opioid risk in part by tapping into individual differences in opioid reinforcing effects. ⋯ Based on placebo-controlled morphine responses, associations were observed between higher scores on a common opioid risk screener (SOAPP-R) and greater desire to take morphine again, fewer negative subjective morphine effects, and greater analgesia. Opioids may provide the best analgesia in those patients at greatest risk of opioid misuse.
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Randomized Controlled Trial Multicenter Study
Lenalidomide for complex regional pain syndrome type 1: lack of efficacy in a phase II randomized study.
Complex regional pain syndrome (CRPS) is a potentially debilitating chronic pain syndrome with a poorly understood but likely neuroimmune/multifactorial pathophysiology associated with axonal injury. Based on the potential contribution of proinflammatory cytokines to CRPS pathogenesis and prior research with thalidomide, we investigated lenalidomide, a thalidomide derivative, for CRPS treatment. We conducted a phase II, randomized, double-blind, placebo-controlled study to evaluate the efficacy of oral lenalidomide 10 mg once daily in consenting patients with unilateral or bilateral CRPS type 1. The study comprised 12 weeks of treatment followed by a long-term extension. The primary efficacy outcome was reduced pain in the index limb, defined as ≥30% improvement from baseline using an 11-point numeric rating scale. One hundred eighty-four subjects enrolled. The primary endpoint was not met because equal proportions of treated (16.1%) and control (16.1%) subjects achieved the outcome; however, lenalidomide was well tolerated, with no evidence of neuropathy or major adverse effects. This study is the largest controlled, blinded clinical trial in subjects with chronic CRPS using the Budapest research criteria. It demonstrates the feasibility of conducting high-quality clinical trials in CRPS type 1 and provides considerations for designing future trials. ⋯ This article reports an adequately powered, controlled clinical trial in subjects with CRPS. Treatment and placebo were equally effective, but the study demonstrated that lenalidomide treatment is feasible in this population. The study provides examples to consider in designing future CRPS trials.
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Randomized Controlled Trial Multicenter Study Comparative Study
Safety and efficacy of once-daily hydromorphone extended-release versus twice-daily oxycodone hydrochloride controlled-release in chinese patients with cancer pain: a phase 3, randomized, double-blind, multicenter study.
Noninferiority of the efficacy of once-daily hydromorphone hydrochloride extended-release (hydromorphone ER) compared with twice-daily oxycodone hydrochloride controlled-release (oxycodone CR) was investigated in this randomized, double-blind study in Chinese patients with moderate to severe cancer pain requiring strong oral opioid analgesics. Randomization (1:1) to hydromorphone ER (8-32 mg) or oxycodone CR (10-40 mg) was followed by dose titration (up to 8 days) and dose maintenance (28 days, weekly visits). Primary endpoint was change from baseline to end of study in "worst pain in the past 24 hours" of Brief Pain Inventory (Short Form) score on last observation carried forward (per protocol set). A total of 137 of 260 randomized patients completed maintenance phase (hydromorphone ER: n = 70; oxycodone CR: n = 67); per protocol set: 81 patients. Mean age was 53.1 years (range: 18-70 years; males: 65.3%); most common Eastern Cooperative Oncology Group performance status = 2. Least square mean difference between 2 treatment groups for primary endpoint using analysis of covariance (baseline score, covariate) was -.1 (95% confidence interval: -1.3, 1.1), with upper bound of 95% confidence interval <1.5 (predefined noninferiority margin). Most common reason for deaths was disease progression (hydromorphone ER: 6.3%; oxycodone CR: 12.7%). Treatment-emergent adverse events were comparable between treatment groups. Hydromorphone ER was noninferior to oxycodone CR in alleviating cancer pain and was well tolerated. ⋯ This article demonstrates clinical noninferiority of the efficacy of once-daily hydromorphone ER compared with twice-daily oxycodone CR in alleviating cancer pain in Chinese patients, with comparable safety profiles between the 2 treatment groups. Thus, a treatment option with the potential for a reduced dosing frequency exists for health care providers and patients.
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Multicenter Study Observational Study
Classification of and risk factors for estrogen deprivation pain syndromes related to aromatase inhibitor treatments in women with breast cancer: a prospective multicenter cohort study.
Aromatase inhibitors (AIs) are the first-line treatment in women with breast cancer for total estrogen depletion. Half the treated women may develop pain, and this condition may therefore be seen as a clinical model of pain related to estrogen deprivation. In this prospective multicenter study, we classified AI-related pain syndromes and identified their predictors. A 1-year, prospective, multicenter cohort study, with 6 visits, was carried out on 135 women with early-stage breast cancer and no pain at the start of AI treatment. At initial assessment, we investigated clinical (demographic and psychosocial, cancer characteristics and treatment, sleep, quality of life), biological (sex hormones, vitamin D, bone biomarkers, oxidative stress, immunologic and inflammatory markers), environmental, and genetic (polymorphism for pain mechanisms) risk factors for pain. During 1 year of follow-up, 77 women (57%) developed pain, leading to AI discontinuation in 12 cases. Five pain syndromes were identified: joint pain (36%), diffuse pain (22%), tendinitis (22%), neuropathic pain (9%), and mixed pain (11%), which are mostly persistent (57%), with diffuse and joint pains the most intense. Risk factors for the development of pain included higher levels of anxiety and impaired quality of life at the initial assessment, whereas cancer characteristics, genetic background, inflammation, and immunologic and hormonal status at baseline were not significant predictors. ⋯ This article presents a classification of AI-related pain syndromes induced by estrogen deprivation that were previously described as arthralgia, but not as neuropathic, diffuse, and mixed pain. This estrogen deprivation-related condition represents a clinical model of pain, and our study identified mostly psychological risk factors for pain development.