The journal of pain : official journal of the American Pain Society
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Increased pressure pain sensitivity and impaired descending pain control have been associated with chronic pain, but knowledge on the variability in the adult general population is lacking. Pressure pain thresholds (PPTs) and descending pain control assessed using conditioned pain modulation (CPM) were recorded in a randomly selected sample (n = 2,199, 53% female) of the Danish adult general population aged 18 to 70 years. PPTs were recorded over the tibialis anterior muscle and the upper trapezius muscle. ⋯ For the trapezius muscle, high perceived stress was associated with lower PPTs (P < .02), whereas an interaction was found between body mass index and sex. CPM potency was lower in female compared with male participants (P ≤ .003), whereas no association with age was found. Higher level of education (P ≤ .05), premature withdrawal from the cold pressor test (P ≤ .02), and high visual analog scale score (P ≤ .02) were associated with a larger CPM response.
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Chronic cancer pain is a serious complication of malignancy or its treatment. Currently, no comprehensive, universally accepted cancer pain classification system exists. Clarity in classification of common cancer pain syndromes would improve clinical assessment and management. Moreover, an evidence-based taxonomy would enhance cancer pain research efforts by providing consistent diagnostic criteria, ensuring comparability across clinical trials. As part of a collaborative effort between the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) and the American Pain Society (APS), the ACTTION-APS Pain Taxonomy initiative worked to develop the characteristics of an optimal diagnostic system. After the establishment of these characteristics, a working group consisting of clinicians and clinical and basic scientists with expertise in cancer and cancer-related pain was convened to generate core diagnostic criteria for an illustrative sample of 3 chronic pain syndromes associated with cancer (ie, bone pain and pancreatic cancer pain as models of pain related to a tumor) or its treatment (ie, chemotherapy-induced peripheral neuropathy). A systematic review and synthesis was conducted to provide evidence for the dimensions that comprise this cancer pain taxonomy. Future efforts will subject these diagnostic categories and criteria to systematic empirical evaluation of their feasibility, reliability, and validity and extension to other cancer-related pain syndromes. ⋯ The ACTTION-APS chronic cancer pain taxonomy provides an evidence-based classification for 3 prevalent syndromes, namely malignant bone pain, pancreatic cancer pain, and chemotherapy-induced peripheral neuropathy. This taxonomy provides consistent diagnostic criteria, common features, comorbidities, consequences, and putative mechanisms for these potentially serious cancer pain conditions that can be extended and applied with other cancer-related pain syndromes.
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Randomized Controlled Trial
Prescription Opioid Taper Support for Outpatients with Chronic Pain: A Randomized Controlled Trial.
Patients receiving long-term opioid therapy for chronic pain and interested in tapering their opioid dose were randomly assigned to a 22-week taper support intervention (psychiatric consultation, opioid dose tapering, and 18 weekly meetings with a physician assistant to explore motivation for tapering and learn pain self-management skills) or usual care (N = 35). Assessments were conducted at baseline and 22 and 34 weeks after randomization. Using an intention to treat approach, we constructed linear regression models to compare groups at each follow-up. ⋯ Pain severity ratings (0-10 numeric rating scale) decreased in both groups at 22 weeks, with no significant difference between groups (adjusted mean difference = -.68; 95% confidence interval, -2.01 to .64; P = .30). The taper support group improved significantly more than the usual care group in self-reported pain interference, pain self-efficacy, and prescription opioid problems at 22 weeks (all P-values < .05). This taper support intervention is feasible and shows promise in reducing opioid dose while not increasing pain severity or interference.
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This study provides national prevalence estimates of US military veterans with severe pain, and compares veterans with nonveterans of similar age and sex. Data used are from the 2010 to 2014 National Health Interview Survey on 67,696 adults who completed the Adult Functioning and Disability Supplement. Participants with severe pain were identified using a validated pain severity coding system imbedded in the National Health Interview Survey Adult Functioning and Disability Supplement. It was estimated that 65.5% of US military veterans reported pain in the previous 3 months, with 9.1% classified as having severe pain. Compared with veterans, fewer nonveterans reported any pain (56.4%) or severe pain (6.4%). Whereas veterans aged 18 to 39 years had significantly higher prevalence rates for severe pain (7.8%) than did similar-aged nonveterans (3.2%), veterans age 70 years or older were less likely to report severe pain (7.1%) than nonveterans (9.6%). Male veterans (9.0%) were more likely to report severe pain than male nonveterans (4.7%); however, no statistically significant difference was seen between the 2 female groups. The prevalence of severe pain was significantly higher in veterans with back pain (21.6%), jaw pain (37.5%), severe headaches or migraine (26.4%), and neck pain (27.7%) than in nonveterans with these conditions (respectively: 16.7%, 22.9%, 15.9%, and 21.4%). Although veterans (43.6%) were more likely than nonveterans (31.5%) to have joint pain, no difference was seen in the prevalence of severe pain associated with this condition. ⋯ Prevalence of severe pain, defined as that which occurs "most days" or "every day" and bothers the individual "a lot," is strikingly more common in veterans than in members of the general population, particularly in veterans who served during recent conflicts. Additional assistance may be necessary to help veterans cope with their pain.
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Patients with complex regional pain syndrome (CRPS) display various abnormalities in central motor function, and their pain is intensified when they perform or just observe motor actions. In this study, we examined the abnormalities of brain responses to action observation in CRPS. We analyzed 3-T functional magnetic resonance images from 13 upper limb CRPS patients (all female, ages 31-58 years) and 13 healthy, age- and sex-matched control subjects. ⋯ A pattern-classification analysis was applied to characterize brain areas where the activation pattern differed between CRPS patients and healthy subjects. Brain areas with statistically significant group differences (q < .05, false discovery rate-corrected) included the hand representation area in the sensorimotor cortex, inferior frontal gyrus, secondary somatosensory cortex, inferior parietal lobule, orbitofrontal cortex, and thalamus. Our findings indicate that CRPS impairs action observation by affecting brain areas related to pain processing and motor control.