Pain
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Comparative Study
Phantom limb pain after amputation in diabetic patients does not differ from that after amputation in nondiabetic patients.
There is a commonly held belief that diabetic amputees experience less phantom limb pain than nondiabetic amputees because of the effects of diabetic peripheral neuropathy; however, evidence to verify this claim is scarce. In this study, a customised postal questionnaire was used to examine the effects of diabetes on the prevalence, characteristics, and intensity of phantom limb pain (PLP) and phantom sensations (PS) in a representative group of lower-limb amputees. Participants were divided into those who had self-reported diabetes (DM group) and those who did not (ND group). ⋯ Using a 0-10 visual analogue scale, the average intensity of PLP was 3.89 (±0.40) for the DM group and 4.38 (±0.41) for the ND group, which was not a statistically significant difference (P=0.402). Length of time since diagnosis of diabetes showed no correlation with average PLP intensity. Our findings suggest that there is no large difference in the prevalence, characteristics, or intensity of PLP when comparing diabetic and nondiabetic amputees, though a larger adjusted comparison would be valuable.
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Given the inherent variability in pain responding, using an "average" pain score may pose serious threats to internal and external validity. Using growth mixture modeling (GMM), this article first examines whether infants can be differentiated into stable groups based on their pain response patterns over a 2-minute post-needle period. Secondary analyses, to specifically address the issue of averaging pain scores to represent a sample, qualitatively described clinically meaningful differences between pain scores of the discerned groups and the overall mean (irrespective of groups). ⋯ Our secondary suggested that the overall mean pain score immediately post-needle reflected most groups well at every age. However, for older infants (6 and 12months, especially), the overall mean pain responses at 1 and 2minutes post-needle significantly over or underestimated groups that contained 48% to 100% of the sample. These results combined highlight the significant variability of infant pain responding patterns between groups of infants and furthermore, calls into question the validity of using an overall mean in research with older infants during the regulatory phase post-needle.
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Randomized Controlled Trial
A randomized, double-blind, placebo-controlled trial of a chemokine receptor 2 (CCR2) antagonist in posttraumatic neuralgia.
We evaluated the analgesic efficacy, safety and tolerability of a novel chemokine receptor 2 (CCR2) antagonist, AZD2423, in posttraumatic neuralgia. This was a double-blind, randomized, parallel-group, multicentre study. One hundred thirty-three patients with posttraumatic neuralgia were equally randomized to 28days' oral administration of 20mg AZD2423, 150mg AZD2423 or placebo. ⋯ The CCR2 antagonist AZD2423 demonstrated no efficacy on NRS average pain scores and most of the secondary pain variables. The NPSI data suggested possible effects on certain sensory components of pain. There were no major safety or tolerability concerns.
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This study investigated the effect on observer responses of the presence/absence of information about medical evidence for pain and psychosocial influences on the patient's pain experience. Additionally, the moderating role of the patient's pain expressions and the mediating role of the observer's belief in deception and evaluation of the patient was examined. Sixty-two participants were presented with videos of 4 patients, each accompanied by a vignette describing the presence or absence of both medical evidence for the pain and psychosocial influences on the patient's pain. ⋯ The results indicate that discounting pain in the absence of medical evidence may involve negative evaluation of the patient. Further, the patient's pain expression is a moderating variable, and psychosocial influences negatively impact the degree to which patients' self-reports are taken into account. The results indicate that contextual information impacts observer responses to pain.
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Persistent postmastectomy pain (PPMP) is a major individual and public health problem. Increasingly, psychosocial factors such as anxiety and catastrophizing are being revealed as crucial contributors to individual differences in pain processing and outcomes. Furthermore, differences in patients' responses to standardized quantitative sensory testing (QST) may aid in the discernment of who is at risk for acute and chronic pain after surgery. ⋯ In contrast, women with PPMP did show elevated levels of distress-related psychosocial factors such as anxiety, depression, catastrophizing, and somatization. Finally, QST in nonsurgical body areas revealed increased sensitivity to mechanical stimulation among PPMP cases, while thermal pain responses were not different between the groups. These findings suggest that an individual's psychophysical and psychosocial profile may be more strongly related to PPMP than their surgical treatment.