Pain
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Review Meta Analysis
Racial and ethnic differences in experimental pain sensitivity: Systematic review and meta-analysis.
Our objective was to describe the racial and ethnic differences in experimental pain sensitivity. Four databases (PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, and PsycINFO) were searched for studies examining racial/ethnic differences in experimental pain sensitivity. Thermal-heat, cold-pressor, pressure, ischemic, mechanical cutaneous, electrical, and chemical experimental pain modalities were assessed. ⋯ Estimates did not vary by pain modalities, nor by other demographic factors; however, SMDs were significantly different based on the sample size. Racial/ethnic differences in experimental pain sensitivity were more pronounced with suprathreshold than with threshold stimuli, which is important in clinical pain treatment. Additional studies examining mechanisms to explain such differences in pain tolerance and pain ratings are needed.
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Randomized Controlled Trial Multicenter Study
Persistent pain after motor vehicle collision: comparative effectiveness of opioids vs nonsteroidal antiinflammatory drugs prescribed from the emergency department-a propensity matched analysis.
Each year millions of Americans present to the emergency department (ED) for care after a motor vehicle collision (MVC); the majority (>90%) are discharged to home after evaluation. Acute musculoskeletal pain is the norm in this population, and such patients are typically discharged to home with prescriptions for oral opioid analgesics or nonsteroidal antiinflammatory drugs (NSAIDs). The influence of acute pain management on subsequent pain outcomes in this common ED population is unknown. ⋯ However, at follow-up participants prescribed opioids were more likely than those prescribed NSAIDs to report use of prescription opioids medications at week 6 (risk difference = 17.5% [95% confidence interval: 5.8%-29.3%]). These results suggest that analgesic choice at ED discharge does not influence the development of persistent moderate to severe musculoskeletal pain 6 weeks after an MVC, but may result in continued use of prescription opioids. Supported by NIAMS R01AR056328 and AHRQ 5K12HS022998.
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Existing estimates of sociodemographic disparities in chronic pain in the United States are based on cross-sectional data, often treat pain as a binary construct, and rarely test for nonresponse or other types of bias. This study uses 7 biennial waves of national data from the Health and Retirement Study (1998-2010; n = 19,776) to describe long-term pain disparities among older (age 51+) American adults. It also investigates whether pain severity, reporting heterogeneity, survey nonresponse, and/or mortality selection might bias estimates of social disparities in pain. ⋯ No evidence of pain-related survey attrition is found, but surveys not accounting for pain severity and reporting heterogeneity are likely to underestimate socioeconomic disparities in pain. The lack of minority disadvantage (net of socioeconomic status) appears genuine. However, the age-related plateauing of pain observed cross-sectionally is not replicated longitudinally, and seems partially attributable to mortality selection, as well as to rising pain levels by birth cohort.
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Recent studies suggest that longer durations of opioid use, independent of maximum morphine equivalent dose (MED) achieved, is associated with increased risk of new-onset depression (NOD). Conversely, other studies, not accounting for duration, found that higher MED increased probability of depressive symptoms. To determine whether rate of MED increase is associated with NOD, a retrospective cohort analysis of Veterans Health Administration data (2000-2012) was conducted. ⋯ Faster rates of MED escalation contribute to NOD, independent of maximum dose, pain, and total opioid duration. Dose escalation may be a proxy for loss of control or undetected abuse known to be associated with depression. Clinicians should avoid rapid dose increase when possible and discuss risk of depression with patients if dose increase is warranted for pain.
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Multicenter Study
Genetic variant rs3750625 in the 3'UTR of ADRA2A affects stress-dependent acute pain severity after trauma and alters a microRNA-34a regulatory site.
α2A adrenergic receptor (α2A-AR) activation has been shown in animal models to play an important role in regulating the balance of acute pain inhibition vs facilitation after both physical and psychological stress. To our knowledge, the influence of genetic variants in the gene encoding α2A-AR, ADRA2A, on acute pain outcomes in humans experiencing traumatic stress has not been assessed. In this study, we tested whether a genetic variant in the 3'UTR of ADRA2A, rs3750625, is associated with acute musculoskeletal pain (MSP) severity following motor vehicle collision (MVC, n = 948) and sexual assault (n = 84), and whether this influence was affected by stress severity. ⋯ In both cohorts, the minor allele at rs3750625 was associated with increased musculoskeletal pain in distressed individuals (stress*rs3750625 P = 0.043 for MVC cohort and P = 0.007 for sexual assault cohort). We further found that (1) miR-34a binds the 3'UTR of ADRA2A, (2) the amount of repression is greater when the minor (risk) allele is present, (3) miR-34a in the IMR-32 adrenergic neuroblastoma cell line affects ADRA2A expression, (4) miR-34a and ADRA2A are expressed in tissues known to play a role in pain and stress, (5) following forced swim stress exposure, rat peripheral nerve tissue expression changes are consistent with miR-34a regulation of ADRA2A. Together, these results suggest that ADRA2A rs3750625 contributes to poststress musculoskeletal pain severity by modulating miR-34a regulation.