The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial Multicenter Study
A 14-week, randomized, double-blinded, placebo-controlled monotherapy trial of pregabalin in patients with fibromyalgia.
The purpose of the study was to assess the efficacy and safety of pregabalin monotherapy in patients with fibromyalgia in a randomized, double-blinded, placebo-controlled trial. After 1 week of single-blinded administration of placebo, 750 patients meeting American College of Rheumatology criteria for fibromyalgia were randomly assigned to pregabalin (300 mg/d, 450 mg/d, 600 mg/d) or placebo, administered twice daily for 14 weeks. The primary outcome variable was comparison of end point mean pain scores, derived from daily diary ratings of pain intensity (0 to 10 scale), between each of the pregabalin groups and the placebo group. If positive, additional primary efficacy parameters included the Patient Global Impression of Change (PGIC) and the Fibromyalgia Impact Questionnaire (FIQ) total score. Compared with placebo-treated patients, mean changes in pain scores at the end point in pregabalin-treated patients were significantly greater (P < .001: 300 mg/d, -0.71; 450 mg/d, -0.98; 600 mg/d, -1.00). Compared with placebo, significantly more pregabalin-treated patients reported improvement on PGIC (P < .01 for all 3 pregabalin doses) and significant improvements in total FIQ score for the 450 mg/d (P = .004) and the 600 mg/d (P = .003) doses. Compared with placebo, all 3 doses of pregabalin were associated with significant improvement in sleep. The most commonly reported pregabalin-related adverse events were dizziness and somnolence, which tended to be dose-related. ⋯ This randomized, placebo-controlled trial of 300, 450, and 600 mg/d of pregabalin monotherapy demonstrated that all 3 doses were efficacious for up to 14 weeks for the treatment of fibromyalgia and were well tolerated by most patients. These results provide evidence that pregabalin is an important treatment option for patients with fibromyalgia.
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Randomized Controlled Trial
Acute opioid administration improves work-related exercise performance in patients with chronic back pain.
We studied the impact of acute opioid administration on work-related exercise performance in patients with chronic back pain. A double-blinded, random-order, placebo-controlled, crossover trial was conducted. Subjects were predominantly men (63%), with a mean age of 49 years. Subjects performed a continuous lifting and lowering test to voluntary fatigue at a load equivalent to 33% of their predetermined maximal lifting load twice: Once after receiving a single intravenous dose of 1 mug/kg fentanyl (a narcotic analgesic) and once after saline placebo. Of the 30 subjects undergoing testing, 3 subjects were unable to complete testing due to medication-induced nausea. Subjects lifted on average 29.4 +/- 17.9 kg under the influence of fentanyl versus 25.6 +/- 3.1 kg with placebo (effect size = 0.23). Time to fatigue was higher in the fentanyl group (312 +/- 251.4 vs 231 +/- 199.9 seconds, effect size = 0.40), and these subjects also performed more total work (7004 +/- 5144 vs 4748 +/- 3147 J, effect size = 0.72). Opioid analgesia improves lifting performance in the short term in individuals with chronic back pain. Longer trials of the effectiveness of opioid analgesia as an adjunct to functional restoration programs are recommended. ⋯ This article presents the results of a clinical trial showing that acute opioid administration improves work-related exercise performance in individuals with chronic back pain. Longer trials of the effectiveness of opioid analgesia as an adjunct to functional restoration programs are recommended.
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Clinical Trial
Fear of pain, pain catastrophizing, and acute pain perception: relative prediction and timing of assessment.
Pain-related fear and catastrophizing are important variables of consideration in an individual's pain experience. Methodological limitations of previous studies limit strong conclusions regarding these relationships. In this follow-up study, we examined the relationships between fear of pain, pain catastrophizing, and experimental pain perception. One hundred healthy volunteers completed the Fear of Pain Questionnaire (FPQ-III), Pain Catastrophizing Scale (PCS), and Coping Strategies Questionnaire-Catastrophizing scale (CSQ-CAT) before undergoing the cold pressor test (CPT). The CSQ-CAT and PCS were completed again after the CPT, with participants instructed to complete these measures based on their experience during the procedure. Measures of pain threshold, tolerance, and intensity were collected and served as dependent variables in separate regression models. Sex, pain catastrophizing, and pain-related fear were included as predictor variables. Results of regression analyses indicated that after controlling for sex, pain-related fear was a consistently stronger predictor of pain in comparison to catastrophizing. These results were consistent when separate measures (CSQ-CAT vs PCS) and time points (pretask vs "in vivo") of catastrophizing were used. These findings largely corroborate those from our previous study and are suggestive of the absolute and relative importance of pain-related fear in the experimental pain experience. ⋯ Although pain-related fear has received less attention in the experimental literature than pain catastrophizing, results of the current study are consistent with clinical reports highlighting this variable as an important aspect of the experience of pain.
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Acceptance of chronic pain has become an important concept in understanding and predicting that chronic pain sufferers can remain engaged with meaningful aspects of life. Assessment of acceptance has been facilitated by the development of Chronic Pain Acceptance Questionnaire (CPAQ). In this study, we aimed to test the reliability and validity of translated Chinese version of CPAQ to use this important tool in the future management of Hong Kong Chinese patients with chronic nonmalignant pain. Content validity was established by consensus formed among a panel of 5 experts in clinical psychology and pain specialty during the process of forward and backward translations. Test-retest reliability was examined by completing the Chinese CPAQ twice, 2 weeks apart, by 54 patients. A total of 224 Chinese patients with chronic nonmalignant pain attending our cluster multidisciplinary pain clinic were asked to complete a battery of psychometric instruments in Chinese, including an intake form for demographic data, Hospital Anxiety and Depression Score (HADS), Medical Outcome Study Short Form 36 (SF-36), Pain Catastrophizing Scale (PCS), and Pain Self-Efficacy Questionnaire (PSEQ). Analysis results showed that Chinese CPAQ had good test-retest reliability (intraclass correlation coefficient, 0.79) and internal consistency reliability (Cronbach alpha = 0.79). The Chinese CPAQ score was significantly correlated to anxiety, depression, pain catastrophizing, pain self-efficacy, and physical and psychosocial disability. Scree plot and Principal Components Factor analysis confirmed the same 2-factor construct as the original English CPAQ. Construct validity of the Chinese CPAQ can therefore be supported. In conclusion, the Chinese CPAQ is a reliable clinical assessment tool with valid construct for acceptance measurement in our heterogeneous Chinese patients sample with chronic nonmalignant pain. ⋯ This article confirms the reliability and validity of a Chinese version of the CPAQ. The Chinese CPAQ can then be used by pain clinicians caring for Chinese chronic pain patients worldwide for acceptance-based psychometric assessment as well as therapies.
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The current study sought to examine how changes in pain-related beliefs and coping responses are related to changes in pain interference and psychological functioning in individuals with spinal cord injuries (SCI) and pain. To measure longitudinal changes in these variables, respondents completed a survey that included measures of pain intensity, pain interference, and psychological functioning, as well as specific psychosocial variables (pain-related beliefs, coping, and social support) and then completed the same survey 6 months later; analyses included only the individuals who reported pain at both times (n = 40). Demographic and injury-related variables were also assessed, but none were found to be significantly associated with changes in functioning. Changes in catastrophizing and belief in one's ability to control pain were each significantly associated with changes in the outcome variables: Greater pain interference and poorer psychological functioning. Changes in specific coping strategies and social support were not predictors of changes in pain, interference, or psychological functioning. These findings support a biopsychosocial model of pain in persons with SCI. Intervention studies targeting maladaptive pain-related beliefs and catastrophizing may help to identify the causal nature of these relationships and may improve multidisciplinary treatment of pain in SCI. ⋯ Intervention studies targeting catastrophizing and maladaptive pain-related beliefs may be the next step in determining which variables play a causal role in the pain interference and psychological functioning of individuals with pain and SCI.