The journal of pain : official journal of the American Pain Society
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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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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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Clinical Trial
Ethnic differences in pain perception and patient-controlled analgesia usage for postoperative pain.
There are reports suggesting that sensitivity to and tolerance of both clinical and experimental pain differ among ethnic groups. We examined self-rated pain score and morphine usage in 1034 women who underwent elective lower cesarian section (LSCS) for their deliveries. Data on pain scores and amount of total morphine use according to patient-controlled analgesia were collected every 4 hours. Overall, lowest pain scores were recorded 12 hours after surgery and highest at 24 hours. Morphine consumption was highest within the first 4 hours and lowest between 12 and 16 hours. There were statistically significant ethnic group differences in pain scores (P = 1.7 x 10(-7)) and morphine usage (P = 2.8 x 10(-15)) between ethnic groups, with Indians having the highest mean pain score and using the highest amount of morphine. The ethnic differences in pain score and morphine self-administration persisted after controlling for age, body mass index, and duration of operation. ⋯ Our findings of highly significant ethnic group difference in self-reported pain level and the amount of analgesia self-administered may have implications on optimal management of acute postoperative pain. Inadequate management of pain after cesarian deliveries might affect the emotional well-being and physical recovery of patients and affect mother-child bonding.
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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.
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Chronic pain after breast cancer surgery is a major problem and is expected to increase in the coming years because of an increased prevalence of breast cancer coupled with better survival. Axillary lymph node dissection (ALND) in patients with breast cancer is associated with nerve damage. The present study investigated the effect of ALND on the prevalence and intensity of chronic pain after breast cancer surgery. Furthermore, we studied the effect of chemotherapy and radiotherapy on chronic pain and the quality of life after breast cancer surgery. We analyzed 317 questionnaires of patients who underwent surgery for breast cancer between 2002 and 2004. In the first part, questions were asked concerning the prevalence of chronic pain, its intensity (visual analog scale), and phantom breast pain. The second part covered quality of life and included the EORTC QLQ-C30/BR-23. The prevalence of chronic pain after breast cancer surgery with ALND is double that without ALND (51% vs 23%). Chronic pain intensity and prevalence of phantom breast pain were not influenced by ALND. Chemotherapy and radiotherapy in interaction with ALND were associated with increased prevalence of chronic pain. The quality of life in patients was mainly affected by chronic pain and to a lesser extent by type of surgery. ⋯ Nerve injury is particularly efficient at producing central sensitization. ALND in conjunction with breast cancer surgery is associated with a doubled prevalence of chronic pain, which has not been described to date. ALND and nerve injury may play a major role in pain chronification after breast cancer surgery.