Pain
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Randomized Controlled Trial
Monthly vitamin D supplementation, pain, and pattern of analgesic prescription: secondary analysis from the randomized, double-blind, placebo-controlled Vitamin D Assessment study.
Observational studies suggest that vitamin D deficiency is associated with higher risk of pain. However, evidence on the effect of vitamin D supplementation on pain is limited and contradictory. The aim of this study was to compare the effect of monthly high-dose vitamin D supplementation on a pain impact questionnaire (PIQ-6) score and prescription of analgesics in the general population. ⋯ Similar results were observed for dispensing of nonsteroidal anti-inflammatory drugs (RR = 0.94; P = 0.24) and other nonopioids (RR = 0.98; P = 0.34). Focusing on vitamin D deficient participants (<50 nmol/L, 24.9%), there was a lower risk of dispensing nonsteroidal anti-inflammatory drugs in the vitamin D group compared with placebo (RR = 0.87; P = 0.009); all other subgroup analyses were not significant. Long-term monthly high-dose vitamin D supplementation did not improve mean PIQ-6 score or reduce analgesic dispensing in the general population.
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Multicenter Study
Racial differences in presentations and predictors of acute pain after motor vehicle collision.
African Americans experience a greater burden of acute pain than non-Hispanic white individuals across of variety of acute medical conditions, but it is unknown whether this is the case after trauma. We evaluated pain, pain-related characteristics (eg, peritraumatic distress), and analgesic treatment in 2 cohorts of individuals (African American [n = 931] and non-Hispanic white [n = 948]) presenting to the emergency department (ED) after a motor vehicle collision. We performed a propensity-matched analysis (n = 796 in each group) to assess racial differences in acute pain in the ED. ⋯ Racial differences in the severity of acute posttraumatic pain after a motor vehicle collision are not explained by factors such as socioeconomic status or crash characteristics. Despite a higher burden of acute pain, African Americans were less likely to receive opioid analgesics and more likely to receive NSAIDs. Further work is needed to understand the relationship between pain severity, disparities in analgesic treatment, and longer term outcomes, such as post-motor vehicle collision chronic pain.
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This study aimed to identify self-report correlates of central pain augmentation in individuals with knee pain. A subset of participants (n = 420) in the Knee Pain and related health In the Community (KPIC) baseline survey undertook pressure pain detection threshold (PPT) assessments. Items measuring specific traits related to central pain mechanisms were selected from the survey based on expert consensus, face validity, item association with underlying constructs measured by originating host questionnaires, adequate targeting, and PPT correlations. ⋯ Pain distribution classified as "pain below the waist additional to knee pain" was more strongly associated with low PPT than were alternative classifications of pain distribution. A single factor, interpreted as "central pain mechanisms," was identified across the 8 selected items and explained variation in PPT (R = 0.17) better than did any originating scale (R = 0.10-0.13). In conclusion, including representative items within a composite self-report tool might help identify people with centrally augmented knee pain.
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Randomized Controlled Trial
Effectiveness of a healthy lifestyle intervention for chronic low back pain: a randomised controlled trial.
We assessed the effectiveness of a 6-month healthy lifestyle intervention, on pain intensity in patients with chronic low back pain who were overweight or obese. We conducted a pragmatic randomised controlled trial, embedded within a cohort multiple randomised controlled trial of patients on a waiting list for outpatient orthopaedic consultation at a tertiary hospital in NSW, Australia. Eligible patients with chronic low back pain (>3 months in duration) and body mass index ≥27 kg/m and <40 kg/m were randomly allocated, using a central concealed random allocation process, to receive advice and education and referral to a 6-month telephone-based healthy lifestyle coaching service, or usual care. ⋯ In the intervention group, 41% (n = 32) of participants reported an adverse event compared with 56% (n = 45) in the control group. Our findings show that providing education and advice and telephone-based healthy lifestyle coaching did not benefit patients with low back pain who were overweight or obese, compared with usual care. The intervention did not influence the targeted healthy lifestyle behaviours proposed to improve pain in this patient group.
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A great need exists for the identification of new effective analgesics to treat sustained pain. However, most preclinical nociceptive assays measure behavioral responses evoked by noxious stimuli (ie, pain-stimulated behavior), which presents a challenge to distinguish between motor impairing and antinociceptive effects of drugs. Here, we demonstrate that chronic constriction injury (CCI) of the sciatic nerve elicits common pain-stimulated responses (ie, mechanical allodynia and thermal hyperalgesia) as well as reduces marble burying/digging behaviors that occur during the early stages of the neuropathy and resolve within 1 week. ⋯ Each of these drugs reversed all CCI-induced nociceptive measures, with the exception of the fatty acid amide hydrolase inhibitor that reversed pain-stimulated behaviors, only. These findings support the use of the mouse marble-burying assay as a model of pain-depressed behavior within the first week of sciatic nerve injury to examine candidate analgesics. These data also support existing preclinical research that cannabinoid receptor agonists and inhibitors of endocannabinoid-regulating enzymes merit consideration for the treatment of pain.