The journal of pain : official journal of the American Pain Society
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Comparative Study
Development of a measure of the burden of pain due to herpes zoster and postherpetic neuralgia for prevention trials: adaptation of the brief pain inventory.
In preparation for clinical trials of a vaccine against herpes zoster (HZ), we conducted a prospective, observational study to evaluate (1) the Zoster Brief Pain Inventory (ZBPI), an HZ-specific questionnaire to quantify HZ pain and discomfort, (2) an operational definition of postherpetic neuralgia (PHN), and (3) a severity-duration measure of the burden of illness caused by HZ. HZ patients aged 60 years or older (n = 121) were enrolled within 14 days of rash onset and completed ZBPI, McGill Pain Questionnaire Present Pain Intensity (PPI), quality of life (QoL), and activities of daily living (ADL) questionnaires on a predetermined schedule. Reliability, measured by intraclass correlation coefficients within 14 days of rash onset, ranged between 0.63 and 0.78. ZBPI pain scores were strongly correlated with other pain measures, interference with ADL, and worsening QoL. The operational definition of PHN, a ZBPI pain score of 3 or greater occurring 90 or more days after rash onset, had high agreement with pain worse than mild on the PPI (kappa = 0.72). The ZBPI pain severity-duration measure had high correlations with severity-duration measures of ADL interference, worsening QoL, and other pain scales. These findings support the validity and utility of the ZBPI, the definition of PHN, and the severity-duration measure of the burden of HZ illness. ⋯ Herpes zoster pain, as measured by the ZBPI severity-duration measure, is associated with impairment in daily living activities and quality of life. The ZBPI measure appears useful for quantifying herpes zoster pain, postherpetic neuralgia, and impairment in daily living activities for clinical trials of herpes zoster prevention.
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Comparative Study
Ethnic differences in pain coping: factor structure of the coping strategies questionnaire and coping strategies questionnaire-revised.
Coping has been examined extensively in the pain literature, although coping instruments have been typically validated in clinical populations with little ethnic diversity. This study examined the factor structure of the Coping Strategies Questionnaire (CSQ) and the CSQ-Revised (CSQ-R) in 650 healthy male and female African American (44%) and white (56%) subjects and explored associations of coping to health and pain-related measures. Factor analyses revealed 6 components for each ethnic group, accounting for comparable amounts of variance and resembling previously reported CSQ subscales. Internal consistency for both ethnic groups was acceptable (0.72-0.91). There were significant main effects for ethnicity on 4 of the CSQ-R scales (P < .05). No ethnic differences in pain or health variables emerged, although when split into high-pain versus minimal-pain groups, differences were revealed on catastrophizing. Results indicate that the factor structure of the CSQ-R in healthy adults is similar to clinical populations and is comparable across African American and white subjects. Group differences on CSQ-R scales suggest potentially important ethnic influences on pain coping. These findings support the use of the CSQ-R to assess coping in African Americans and in healthy young adults. Additional clinical research is needed to determine the practical importance of group differences in pain coping. ⋯ Coping has been examined extensively in the pain literature, although coping instruments typically have been validated in clinical populations with little ethnic diversity. This study examines the factor structure of the CSQ-Revised in an ethnically diverse population and supports the use of the CSQ-R to assess coping in African Americans and in healthy young adults.
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Comparative Study
Population-based survey of pain in the United States: differences among white, African American, and Hispanic subjects.
A cross-sectional telephone survey was conducted in nationally representative probability sample of non-Hispanic white subjects, non-Hispanic African American subjects, and Hispanic subjects of any race to explore relationships between chronic pain and race or ethnicity. Approximately one third in each group reported "frequent or persistent pain" for 3 months or longer during the past year, and approximately one third of the 454 white subjects, 447 African American subjects, and 434 Hispanic subjects in the final sample experienced "disabling pain" (defined as both high severity and high functional interference). White subjects had pain longer but with lesser intensity than the other groups, and pain-related life interference did not vary. Significantly fewer Hispanic subjects (68%) than white subjects (82%) or African American subjects (85%) had visited a physician for pain, and African American subjects (81%) were more likely than white subjects (75%) or Hispanic subjects (63%) to have used prescription medications. Disabling pain was positively associated with female sex (odds ratio [OR], 1.45), income of $25,000 or less (OR, 1.71), less than a high school education (OR, 1.72), and divorce (OR, 1.69) and was negatively associated with younger age (18-34 years; OR, 0.68), income between $25,000 and $74,999 (OR, 0.64) or $75,000 or more (OR, 0.37), being employed (OR, 0.48), suburban residence (OR, 0.64), and having a college (OR, 0.51) or graduate (OR, 0.32) degree. Multivariate logistic regression found that income of $25,000 or less (OR, 2.54), less than a high school education (OR, 1.59), and being unemployed (OR, 1.50) remained significant when other factors were controlled. Neither race nor ethnicity predicted disabling pain, but the minorities had more characteristics identified as predictors. The data suggest that race and ethnicity contribute to clinical diversity, but socioeconomic disadvantage is the more important predictor of disabling pain. ⋯ Race and ethnicity influence the presentation and treatment of chronic pain. This study evaluated community-dwelling white, African American, and Hispanic subjects by using a sophisticated telephone survey methodology. Pain was highly prevalent across groups, and there were racial and ethnic differences in pain experience and treatment preferences. Race and ethnicity were not independently associated with severe pain, but both minorities were more likely to possess the socioeconomic and educational characteristics that were associated.
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Comparative Study
Body pain area and pain-related negative affect predict clinical pain intensity in patients with fibromyalgia.
Patients with fibromyalgia (FM) report widespread chronic musculoskeletal pain. Palpation of 9 paired tender points (TPs) is commonly used for the diagnosis of FM according to criteria specified by the American College of Rheumatology. Although TP palpation can be used to assess deep tissue hypersensitivity, it has failed as a reliable indicator of clinical pain intensity in FM. The sum of local areas of pain (SLAP) obtained from a body pain diagram represents a relevant measure of the spatial extent of clinical pain, a feature most likely important for FM pain. Because spatial summation of pain can be an important determinant of clinical pain intensity, we hypothesized that this measure would predict clinical pain intensity in FM patients. Because pain is strongly associated with negative emotions, we evaluated the relationship of pain-related negative affect (PRNA) with clinical pain intensity in FM. The independent contributions of SLAP, PRNA, and TP count to the variance of clinical pain intensity were assessed in 280 FM patients. Clinical pain intensity of 280 FM patients was measured by using a visual analogue scale. FM patients shaded all painful body areas on body pain diagrams. Dolorimetry was used for TP evaluations. PRNA was assessed with the Medical College of Virginia Pain Questionnaire. Hierarchical linear regression was used to test the association of SLAP, TPs, and PRNA with clinical pain intensity. FM patients' mean visual analogue scale rating (0 to 100) of usual clinical pain was 50.1. Mean SLAP, TP count, and PRNA were 11.4, 16.0, and 44.3, respectively. Hierarchical linear regression analysis identified SLAP, TP count, and PRNA as independent predictors of clinical pain that accounted for 45% of the variance in clinical pain intensity ratings in FM patients. Consistent with the literature, TP count predicted only a small part (4%) of this variance. Our statistical model of body pain areas and negative affect predicts a large portion of the variance of pain intensity in FM. This result suggests that the extent of pain areas and negative emotions are uniquely associated with clinical pain intensity in FM. ⋯ The number of painful body areas obtained by body pain diagrams is a better predictor of clinical pain intensity than TPs in FM patients. The combination of painful body areas, TP counts, and PRNA predicts 45% of the clinical pain intensity of FM patients. This finding might be useful for clinical evaluations of FM patients.
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Chemical acupuncture with diluted bee venom (DBV), termed apipuncture, has been traditionally used in oriental medicine to treat several inflammatory diseases and chronic pain conditions. In the present study we investigated the potential antihyperalgesic and antiallodynic effects of apipuncture in a rat neuropathic pain model. DBV (0.25 mg/kg, subcutaneous) was injected into the Zusanli acupoint 2 weeks after chronic constrictive injury (CCI) of the sciatic nerve. Between 5 and 45 minutes after DBV injection, we observed a significant reduction in the thermal hyperalgesia induced by CCI, but apipuncture failed to reduce CCI-induced mechanical allodynia. We subsequently examined whether this antihyperalgesic effect of apipuncture was related to the activation of spinal opioid receptors and/or alpha2-adrenoceptors. Intrathecal pretreatment with naloxone (10 microg/rat), an opioid receptor antagonist, did not reverse the antihyperalgesic effect of apipuncture, whereas pretreatment with idazoxan (40 microg/rat), an alpha2-adrenoceptor antagonist, completely blocked the effect of apipuncture. These results indicate that DBV-induced apipuncture significantly reduces the thermal hyperalgesia generated by CCI and also suggest that this antihyperalgesic effect is dependent on the activation of alpha2-adrenoceptors, but not opioid receptors, in the spinal cord. ⋯ The antinociceptive effect of apipuncture was evaluated in a rodent neuropathic pain model. The relieving effect of apipuncture on thermal hyperalgesia was found to be mediated by spinal alpha2-adrenoceptors, but not opioid receptors. These data suggest that apipuncture might be an effective alternative therapy for patients with painful peripheral neuropathy, especially for those who are poorly responsive to opioid analgesics.