Ethnic differences in pain tolerance: clinical implications in a chronic pain population

Changes in widespread pain after surgical weight loss in racialized adults: A secondary analysis from a two-year longitudinal study

Widespread pain is associated with reduced function and disability. Importantly, three-fourths of the approximately 42% of U.S. adults with obesity have widespread pain. Moreover, rates of adult obesity are higher and widespread outcomes are worse in racialized non-Hispanic Black and Hispanic/Latino/a/X groups, potentially exacerbating existing pain disparities. Bariatric surgery significantly reduces weight and improves pain. However, recurrent or unresolved pain after bariatric surgery can hinder weight loss or facilitate weight regain. The current study conducted a secondary analysis of a longitudinal study of predictors and mechanisms of weight loss after bariatric surgery to examine the point prevalence of widespread pain and pain trajectories 24 months post-surgery. Our secondary aim was to examine the association between weight loss and pain characteristics. Our exploratory aim was to longitudinally examine racial differences in pain trajectories after bariatric surgery. Our results showed that point prevalence decreased after bariatric surgery. Additionally, significant improvements in pain trajectories occurred within the first 3 months post-surgery with a pattern of pain reemergence beginning at 12 months post-surgery. Hispanic/Latino/a/X participants reported a higher number of painful anatomical sites before bariatric surgery, and the rate of change in this domain for this group was faster compared to the racialized non-Hispanic Black participants. These findings suggest that pain improvements are most evident during the early stages of surgical weight loss in racialized populations of adults with widespread pain. Thus, clinicians should routinely monitor patients' weight changes after bariatric surgery as they are likely to correspond to changes in their pain experiences. PERSPECTIVE: This article presents the prevalence and pain trajectories of racialized adults with widespread pain (WP) after surgical weight loss. Clinicians should evaluate changes in the magnitude and spatial distribution of pain after significant weight change in these populations so pain interventions can be prescribed with greater precision.

Looking on the bright side: The relationships between flourishing and pain-related outcomes among adolescents living with chronic pain

A deficits-based approach to adolescent chronic pain currently dominates the literature, to the exclusion of positive approaches, such as flourishing. Addressing this knowledge gap, this study examined the relationships between flourishing and pain-related outcomes in adolescent chronic pain. Seventy-nine adolescents aged 11-24 years were asked to complete self-report measures of three domains of flourishing and four pain-related outcomes. Correlation coefficients and four hierarchical linear regression analyses were conducted, controlling for age and gender. Flourishing mental health was associated with, and significantly contributed to explaining, anxiety and depressive symptoms, and social and family functioning impairment. Benefit finding and posttraumatic growth were each associated with social and family functioning impairment, while posttraumatic growth was also associated with anxiety and depressive symptoms. Additionally, benefit finding significantly contributed to explaining pain intensity. Study findings underscore the importance of assessing the relationships between flourishing and pain-related outcomes in adolescents with chronic pain.

Unraveling the Tapestry of Pain: A Comprehensive Review of Ethnic Variations, Cultural Influences, and Physiological Mechanisms in Pain Management and Perception

The medical management of pain is a nuanced challenge influenced by sociocultural, demographic, and ethical factors. This review explores the intricate interplay of these dimensions in shaping pain perception and treatment outcomes. Sociocultural elements, encompassing cultural beliefs, language, societal norms, and healing practices, significantly impact individuals' pain experiences across societies. Gender expectations further shape these experiences, influencing reporting and responses. Patient implications highlight age-related and socioeconomic disparities in pain experiences, particularly among the elderly, with challenges in managing chronic pain and socioeconomic factors affecting access to care. Healthcare provider attitudes and biases contribute to disparities in pain management across racial and ethnic groups. Ethical considerations, especially in opioid use, raise concerns about subjective judgments and potential misuse. The evolving landscape of placebo trials adds complexity, emphasizing the importance of understanding psychological and cultural factors. In conclusion, evidence-based guidelines, multidisciplinary approaches, and tailored interventions are crucial for effective pain management. By acknowledging diverse influences on pain experiences, clinicians can provide personalized care, dismantle systemic barriers, and contribute to closing knowledge gaps, impacting individual and public health, well-being, and overall quality of life.

Environmental and sociocultural factors are associated with pain-related brain structure among diverse individuals with chronic musculoskeletal pain: intersectional considerations

Chronic musculoskeletal pain including knee osteoarthritis (OA) is a leading cause of disability worldwide. Previous research indicates ethnic-race groups differ in the pain and functional limitations experienced with knee OA. However, when socioenvironmental factors are included in analyses, group differences in pain and function wane. Pain-related brain structures are another area where ethnic-race group differences have been observed. Environmental and sociocultural factors e.g., income, education, experiences of discrimination, and social support influence brain structures. We investigate if environmental and sociocultural factors reduce previously observed ethnic-race group differences in pain-related brain structures. Data were analyzed from 147 self-identified non-Hispanic black (NHB) and non-Hispanic white (NHW), middle and older aged adults with knee pain in the past month. Information collected included health and pain history, environmental and sociocultural resources, and brain imaging. The NHB adults were younger and reported lower income and education compared to their NHW peers. In hierarchical multiple regression models, sociocultural and environmental factors explained 6-37% of the variance in pain-related brain regions. Self-identified ethnicity-race provided an additional 4-13% of explanatory value in the amygdala, hippocampus, insula, bilateral primary somatosensory cortex, and thalamus. In the rostral/caudal anterior cingulate and dorsolateral prefrontal cortex, self-identified ethnicity-race was not a predictor after accounting for environmental, sociocultural, and demographic factors. Findings help to disentangle and identify some of the factors contributing to ethnic-race group disparities in pain-related brain structures. Numerous arrays of environmental and sociocultural factors remain to be investigated. Further, the differing sociodemographic representation of our NHB and NHW participants highlights the role for intersectional considerations in future research.

Pain outcome of non-instrumented lumbar decompressive surgery for degenerative lumbar spine disease using patient-reported pain outcome instruments

Objectives

A clinical disorder known as degenerative lumbar spine disease (DLSD) is characterized by persistent low back pain (LBP) coupled with radiculopathy and other signs of neurologic impairment. Using patient-reported pain outcome assessment tools, this study evaluated the pain outcome of non-instrumented lumbar decompressive surgery for DLSD.

Materials and Methods

A prospective longitudinal research was conducted. Using the metric visual analog scale (VAS) score and the Oswestry disability index (ODI), consenting patients who underwent non-instrumented lumbar decompressive surgery for symptomatic DLSD were evaluated for radicular pain and LBP. The evaluation was conducted both immediately before surgery and 6 months after surgery. Data generated by comparing the pre-operative and post-operative VAS and ODI scores were then analyzed using descriptive and inferential statistics.

Results

Sixty-seven patients in total completed the study. Thirty-six (54%) males and 31 (46%) females, with a mean age and body mass index of 55.28 years and 29.5 k/m2, respectively. At 6 months postoperatively, there was significant pain reduction from the pre-operative baseline VAS for LBP (67.12-32.74) with P < 0.001, VAS for radicular pain (75.39-32.75) with P < 0.001, and ODI (65.30-27.66) with P < 0.001. There was a greater decrease in radicular pain than in LBP following lumbar decompressive only surgery (P = 0.03).

Conclusion

Patients with symptomatic DLSD and high pre-operative back pain scores without considerable listhesis should anticipate a significant reduction in radicular and back pain intensity, as well as pain-related functional disability, 6 months after non-instrumented lumbar decompressive surgery.

Predicting Pain Intensity after Mandibular Third Molar Surgery using Cold Pressor Testing: A Quasi-Experimental Study

BACKGROUND

Patients complain differently about their experiences of post-operative pain. However, clinicians are often guided by their own viewpoints despite the highly subjective nature of pain resulting in suboptimal post-operative pain management. This impacts negatively on the quality of life of patients in the immediate post-operative period. Investigating patients' pain behavior in the pre-operative period may therefore help to predict the intensity of post-operative pain, thereby assisting in identifying patients who are at risk of greater pain after third molar surgery, and allocating extra resources for pain control.

AIM

This study aims to predict the intensity of pain after third molar surgery by correlating post-operative pain perception with the sensory-discriminative dimension and affective response to a cold pressor stimulus.

MATERIALS AND METHODS

This study is a quasi-experimental study that was conducted in the oral surgery clinic of (name of hospital in the title page). The procedure was undertaken in an isolated clinic cubicle with well-controlled room temperature and minimal distraction. Study participants were recruited by convenience sampling. Forty-three consenting participants, 20 years and above, who met eligibility criteria were subjected to pre-operative cold pressor testing. Subsequently, third molar surgery was done and post-operative pain intensity was recorded at specific intervals. Data analyses were completed using IBM SPSS version 25. The Kolmogorov-Smirnov (KS) test was used to test for normality of continuous variables. Ordinal regression was used to test for contributory value of pre-operative measurement while Spearman's rank correlation test was used to test their degree of relationships with post-operative pain P < 0.05.

RESULT

The median pain threshold was 20 s (Interquartile Range, IQR 12.75-32.25) and the median pain tolerance was 33 s (IQR = 23.00-54.00) from the cold pressor test. The peak median pain score in this study was reached at 3-h after the last stitch. There was a statistically significant predictive effect of both variables on post-operative pain at 3-h.

CONCLUSION

Sensory-discriminative dimension and affective response to cold pressor test are significant predictors of peak post-operative pain after impacted mandibular third molar surgery.

Environmental and sociocultural factors are associated with pain-related brain structure among diverse individuals with chronic musculoskeletal pain

Chronic musculoskeletal pain is a leading cause of disability worldwide. Previous research indicates ethnic/race groups are disproportionately affected by chronic pain conditions. However, when considering socioenvironmental factors these disparities are no longer observed. Ethnic/race group differences have also been reported in pain-related brain structure. Given that environmental and sociocultural factors influence biology and health outcomes, this study aimed to investigate possible environmental and sociocultural contributions to structural differences in pain-related brain regions. A total of 147 non-Hispanic black and non-Hispanic white, middle and older aged adults with knee pain in the past month and a brain MRI are included in the analyses. Individuals also provided information specific to health and pain history and environmental and sociocultural resources. In hierarchical multiple regression models, sociocultural and environmental factors explained 6%-37% of the variance in thickness of pain-related brain regions, with seven of the eight brain regions being statistically significant. In the amygdala, hippocampus, insula, bilateral primary somatosensory cortex, and thalamus, ethnicity/race provided an additional 4%-13% of explanatory value. In the rostral/caudal anterior cingulate and dorsolateral prefrontal cortex, ethnicity/race was not a predictor after accounting for environmental, sociocultural, and other demographic measures. Findings inform health disparities research by elucidating the complexity of factors contributing to previously reported ethnicity/race group differences.

Usability and acceptability of virtual reality for chronic pain management among diverse patients in a safety-net setting: a qualitative analysis

Objective

The aim of this study was to understand the usability and acceptability of virtual reality (VR) among a racially and ethnically diverse group of patients who experience chronic pain.

Materials and Methods

Using the Technology Acceptance Model theory, we conducted semistructured interviews and direct observation of VR use with English-speaking patients who experience chronic pain treated in a public healthcare system (n = 15), using a commercially available VR technology platform. Interviews included questions about current pain management strategies, technology use, experiences and opinions with VR, and motivators for future use.

Results

Before the study, none of the 15 participants had heard about or used VR for pain management. Common motivators for VR use included a previous history of substance use and having exhausted many other options to manage their pain and curiosity. Most participants had a positive experience with VR and 47% found that the VR modules distracted them from their pain. When attempting the navigation-based usability tasks, most participants (73%-92%) were able to complete them independently.

Discussion

VR is a usable tool for diverse patients with chronic pain. Our findings suggest that the usability of VR is not a barrier and perhaps a focus on improving the accessibility of VR in safety-net settings is needed to reduce disparities in health technology use.

Conclusions

The usability and acceptability of VR are rarely studied in diverse patient populations. We found that participants had a positive experience using VR, showed interest in future use, and would recommend VR to family and friends.

Covariate Adjustment in Chronic Pain Trials: An Oft-Missed Opportunity

Self-reported pain intensity, frequently used as an outcome in randomized clinical trials (RCTs) of chronic pain, is often highly variable and could be associated with multiple baseline factors. Thus, the assay sensitivity of pain trials (ie, the ability of the trial to detect a true treatment effect) could be improved by including prespecified baseline factors in the primary statistical model. The objective of this focus article was to characterize the baseline factors included in statistical analyses of chronic pain RCTs. Seventy-three RCTs published between 2016 and 2021 that investigated interventions for chronic pain were included. The majority of trials identified a single primary analysis (72.6%; n = 53). Of these, 60.4% (n = 32) included one or more covariates in the primary statistical model, most commonly baseline value of the primary outcome, study site, sex, and age. Only one of the trials reported information regarding associations between covariates and outcomes (ie, information that could inform prioritization of covariates for prespecification in future analyses). These findings demonstrate inconsistent use of covariates in the statistical models in chronic pain clinical trials. Prespecified adjustments for baseline covariates that could increase precision and assay sensitivity should be considered in future clinical trials of chronic pain treatments. PERSPECTIVE: This review demonstrates inconsistent inclusion and potential underutilization of covariate adjustment in analyses of chronic pain RCTs. This article highlights areas for possible improvement in design and reporting related to covariate adjustment to improve efficiency in future RCTs.

Addressing chronic pain disparities between Black and White people: a narrative review of socio-ecological determinants

A 2019 review article modified the socio-ecological model to contextualize pain disparities among different ethnoracial groups; however, the broad scope of this 2019 review necessitates deeper socio-ecological inspection of pain within each ethnoracial group. In this narrative review, we expanded upon this 2019 article by adopting inclusion criteria that would capture a more nuanced spectrum of socio-ecological findings on chronic pain within the Black community. Our search yielded a large, rich body of literature composed of 174 articles that shed further socio-ecological light on how chronic pain within the Black community is influenced by implicit bias among providers, psychological and physical comorbidities, experiences of societal and institutional racism and biomedical distrust, and the interplay among these factors. Moving forward, research and public-policy development must carefully take into account these socio-ecological factors before scaling up pre-existing solutions with questionable benefit for the chronic pain needs of Black individuals.

Patterns and disparities in prescribing of opioids and benzodiazepines for older adults in North Carolina

BACKGROUND

We characterized real-world prescribing patterns of opioids and benzodiazepines (BZDs) for older adults to explore potential disparities by race and sex and to characterize patterns of co-prescribing.

METHODS

A retrospective evaluation was conducted using electronic health data for adults ≥65 years old who presented to one of 15 primary care practices between 2019 and 2020 (n = 25,141). Chronic opioid and BZD users had ≥4 prescriptions in the year prior, with at least one in the last 90 or 180 days, respectively. We compared demographic characteristics between all older adults versus chronic opioid and BZD users. We used logistic regression to identify characteristics (age, sex, race, Medicaid use, fall history) associated with opioid and BZD co-prescribing.

RESULTS

We identified 833 (3.3%) chronic opioid and 959 chronic BZD users (3.8%) among all older adults seen in these practices. Chronic opioid users were less likely to be Black (12.7% vs. 14.3%) or other non-White race (1.4% vs. 4.3%), but more likely to be women (66.8% vs. 61.3%). A similar trend was observed for BZD users, with less prescribing among Black (5.4% vs. 14.3%) and other races (2.2% vs. 4.3%) older adults and greater prescribing among women (73.6% vs. 61.3%). Co-prescribing was observed among 15% of opioid users and 13% of BZD users. Co-prescribing was largely driven by the presence of relevant co-morbid conditions including chronic pain, anxiety, and insomnia rather than demographic characteristics.

CONCLUSIONS

We observed notable disparities in opioid and BZD prescribing by sex and race among older adults in primary care. Future research should explore if such patterns reflect appropriate prescribing or are due to disparities in prescribing driven by biases related to perceived risks for misuse.

The Importance of the Treatment Rationale for Pain in Animal-Assisted Interventions: A Randomized Controlled Trial in Healthy Participants

Animal-assisted interventions (AAIs) is a promising treatment approach for pain, but possible mechanisms still need to be elucidated. This study set out to investigate the analgesic effects of an animal provided with a treatment rationale in a randomized controlled trial employing a standardized experimental heat-pain paradigm. We randomly assigned 128 healthy participants to: dog treatment (DT), placebo treatment (PT), dog and placebo treatment (DPT), and no treatment (NT). Primary outcomes were heat-pain tolerance and the corresponding self-reported ratings of pain unpleasantness and intensity. Results revealed no differences in heat-pain tolerance between the conditions. However, participants in the DT condition experienced heat-pain as significantly less unpleasant at the limit of their tolerance compared to participants in the NT condition (estimate = -0.96, CI = -1.58 to 0.34, P = .010). Participants in the DT condition also showed lower ratings of pain intensity at the limit of their tolerance compared to participants in the NT condition (estimate = -0.44, CI = -0.89 to 0.02, P = .060). This study indicates that a dog has analgesic effects on pain perception when integrated into the treatment rationale. We assume that providing a treatment rationale regarding the animal is important in AAIs for pain. PERSPECTIVE: This study shows that the presence of an animal is not sufficient for animal-assisted interventions (AAIs) to have an analgesic effect on pain unless they are provided with a treatment rationale. This could imply that not only the animal but also contextual factors are important in AAIs. TRIAL REGISTRATION: Clinical Trials NCT04361968.

Comparison of spinal versus general anesthesia on the perioperative blood glucose levels in patients undergoing lower abdominal and pelvic surgery: a prospective cohort study, Ethiopia

Surgery is linked with fear and stress that disrupt metabolic and neuroendocrine activities, which impair normal maintained glucose metabolism that leads to stress hyperglycaemia. This study aimed to compare the effect of general and spinal anaesthesia on perioperative blood glucose levels in patients undergoing lower abdominal and pelvic surgery.

Methods

This prospective observational cohort study recruits 70 adult patients who underwent lower abdominal and pelvic surgery under general and spinal anaesthesia; 35 in each group. A systematic random sampling technique was used to select study participants. Capillary blood glucose was measured at four perioperative times. An independent t-test, dependent t-test, and Manny-Whitney U test were used for statistical analysis, as appropriate. P values less than 0.05 were considered statistically significant.

Results

No statistically significant difference was observed in mean blood glucose levels at baseline and 5 min after induction of general anaesthesia and complete blocks of spinal anaesthesia. But at the end of surgery and 60 min after the end of surgery the mean blood glucose levels were statistically significantly higher in the general anaesthesia group compared with the spinal anaesthesia group (P<0.05). And the blood glucose level was significantly increased from baseline compared with the different time intervals in the general anaesthesia group.

Conclusion

The mean blood glucose levels were lower in patients undergoing surgery under spinal anaesthesia compared with general anaesthesia. The authors recommend spinal over general anaesthesia whenever possible for patients undergoing lower abdominal and pelvic surgery.

Societal impact on older persons' chronic pain: Roles of age stereotypes, age attribution, and age discrimination

RATIONALE

In view of the severity and prevalence of chronic pain, combined with the limited success of long-term treatments, there is the need for a more expansive understanding of its etiology. We therefore investigated over time three societal-based potential determinants of chronic pain that were previously unexamined in this connection: negative age stereotypes, age attribution, and age discrimination.

METHODS

The cohort consisted of 1373 Americans aged 55 and older, who participated in four waves of the National Health and Resilience in Veterans Study, spanning seven years.

RESULTS

Consistent with the hypotheses, negative age stereotypes as well as age discrimination predicted chronic pain, and age attribution acted as a mediator between the negative age stereotypes and chronic pain. In a subset of participants who were free of chronic pain at baseline, those who had assimilated negative age stereotypes were 32% more likely to develop chronic pain in the next seven years than those who had assimilated positive age stereotypes.

CONCLUSION

Our finding that the three societal-based and modifiable predictors contributed to chronic pain refutes the widely held belief that chronic pain experienced in later life is entirely and inevitably a consequence of aging.

Preoperative and Postoperative Hyperalgesia in Dental Patients on Chronic Opioid Therapy: A Pilot Study

OBJECTIVE

Opioid-induced hyperalgesia, a paradoxical increase in pain sensitivity associated with ongoing opioid use, may worsen the postoperative pain experience. This pilot study examined the effect of chronic opioid use on pain responses in patients undergoing a standardized dental surgery.

METHODS

Experimental and subjective pain responses were compared prior to and immediately following planned multiple tooth extractions between patients with chronic pain on opioid therapy (≥30 mg morphine equivalents/d) and opioid-naïve patients without chronic pain matched on sex, race, age, and degree of surgical trauma.

RESULTS

Preoperatively, chronic opioid users rated experimental pain as more severe and appreciated less central modulation of that pain than did opioid-naïve participants. Postoperatively, chronic opioid-using patients rated their pain as more severe during the first 48 hours and used almost twice as many postoperative analgesic doses during the first 72 hours as the opioid-naïve controls.

CONCLUSION

These data suggest that patients with chronic pain taking opioids approach surgical interventions with heightened pain sensitivity and have a more severe postoperative pain experience, providing evidence that their complaints of postoperative pain should be taken seriously and managed appropriately.

Preliminary Evidence for the Sequentially Mediated Effect of Racism-Related Stress on Pain Sensitivity Through Sleep Disturbance and Corticolimbic Opioid Receptor Function

Sleep disturbance predicts worse pain outcomes. Because sleep disturbance inequitably impacts Black adults - with racism as the upstream cause - understanding how racism-related stress impacts pain through sleep might help minimize racialized pain inequities. This preliminary study examined sequential mediation of the effect of racism-related stress on experimental pain through sleep disturbance and corticolimbic μOR function in pain-free non-Hispanic Black (NHB) and White (NHW) adults. Participants completed questionnaires, actigraphy, positron emission tomography, and sensory testing. We reproduced findings showing greater sleep disturbance and pain sensitivity among NHB participants; greater sleep disturbance (r = .35) and lower pain tolerance (r=-.37) were significantly associated with greater racism-related stress. In a sequential mediation model, the total effect of racism-related stress on pain tolerance (β=-.38, P = .005) weakened after adding sleep disturbance and ventromedial prefrontal cortex (vmPFC) μOR binding potential (BPND) as mediators (β = -.18, P = .16). The indirect effect was statistically significant [point estimate = -.003, (-.007, -.0003). Findings showed a potential sequentially mediated effect of racism-related stress on pain sensitivity through sleep disturbance and vmPFC μOR BPND. As policy efforts are enacted to eliminate the upstream cause of systemic racism, these results cautiously suggest that sleep interventions within racism-based trauma informed therapy might help prevent downstream effects on pain. PERSPECTIVE: This preliminary study identified the effect of racism-related stress on pain through sleep disturbance and mu-opioid receptor binding potential in the ventromedial prefrontal cortex. Findings cautiously support the application of sleep interventions within racism-based trauma-informed therapy to prevent pain inequities as policy changes function to eliminate all levels of racism.

The role of dispositional mindfulness in the fear-avoidance model of pain

OBJECTIVE

The fear-avoidance model of pain posits that a painful stimulus is interpreted through pain catastrophizing, which leads to negative downstream cognitions, emotions, and behaviors that shape the experience of pain. As dispositional mindfulness is associated with less catastrophizing and pain, some researchers have suggested incorporating mindfulness into the fear-avoidance model. Across two studies, we empirically tested dispositional mindfulness as a stand-alone component within the fear-avoidance model of pain.

METHODS

Two independent, online cross-sectional surveys (Ns = 362 and 580 U.S. adults) were conducted. Participants completed validated assessments of mindfulness, pain catastrophizing, fear of pain, pain vigilance, depression, pain intensity, and pain sensitivity. Using structural equation modeling, we tested the inclusion of dispositional mindfulness in the fear-avoidance model of pain. We proposed that greater mindfulness would be associated with less pain catastrophizing, which in turn would be associated with less fear of pain, leading to less depression, and then ultimately less pain intensity and pain sensitivity.

RESULTS

Across both studies, the fear-avoidance model of pain did not fit the data well, with or without mindfulness included. We found that a simplified model fit the data best (Study 1: χ2/df = 1.83; CFI = .981; RMSEA = .049, 90% CI [0.019, 0.076]; SRMR = 0.031; Study 2: χ2/df = 2.23; CFI = .976; RMSEA = .046, 90% CI [0.026, 0.067]; SRMR = .031), such that greater mindfulness was significantly associated with less pain catastrophizing and, in turn, lower levels of pain intensity and pain sensitivity.

CONCLUSION

Our findings suggest that a simplified model, compared to the traditional fear-avoidance model, may partly explain the experience of pain among individuals without chronic pain. Future work should examine the temporal associations among these variables to inform the employment of future empirically supported interventions for pain management.

Application of multilevel models for predicting pain following root canal treatment

OBJECTIVES

This study developed predictive models for one-week acute and six-month persistent pain following root canal treatment (RCT). An additional aim was to study the gain in predictive efficacy of models containing clinical factors only, over models containing sociodemographic characteristics.

METHODS

A secondary data analysis of 708 patients who received RCTs was conducted. Three sets of predictors were used: (1) combined set, containing all predictors in the data set; (2) clinical set and (3) sociodemographic set. Missing data were handled by multiple imputation using the missing indicator method. The multilevel least absolute selection and shrinkage operator (LASSO) regression was used to select predictors into the final multilevel logistic models. Three measures, the area under the receiver operating characteristic curve (AUROC) and precision-recall curve (AUPRC) and calibration curves, were used to assess the predictive performance of the models.

RESULTS

The selected-in factors in the final models, using LASSO regression, are related to pre- and intra-treatment clinical symptoms and pain experience. Predictive performance of the models remained the same with the inclusion (exclusion) of the socio-demographic factors. For predicting one-week outcome, the model built with combined set of predictors yielded the highest AUROC and AUPRC of 0.85 and 0.72, followed by the models built with clinical factors (AUROC = 0.82, AUPRC = 0.66). The lowest predictive ability was found in models with only sociodemographic characteristics (AUROC = 0.68, AUPRC = 0.40). Similar patterns were observed in predicting six-month outcome, where the AUROC for models with combined, clinical and sociodemographic sets of predictors were 0.85, 0.89 and 0.66, respectively, and the AUPRC were 0.48, 0.53 and 0.22, respectively.

CONCLUSIONS

Clinical factors such as the severity and experience of pre-operative and intra-operative pain were discovered important to the subsequent development of pain following RCTs. Adding sociodemographic characteristics to the models with clinical factors did not change the models' predictive performance or the proportion of explained variance.

Diagnostic Accuracy Rates of Appendicitis Scoring Systems for the Stratified Age Groups

BACKGROUND

Many scoring systems have been developed for acute appendicitis, which is the most common emergent disorder in surgical practice. Considering the physiological changes and chronic diseases occurring with advancing age, an applied scoring system may not produce the same score in similar patients in all age groups.

OBJECTIVES

We aimed to compare the predictive values of scoring systems in different age groups.

METHODS

In this prospective study, the patients operated on in our clinic with a prediagnosis of acute appendicitis between March 2020 and March 2021 were included. We divided them into three age groups as 18-45 years (group 1), 46-65 years (group 2), and >65 years (group 3). We compared the scores of the nine acute appendicitis scoring systems most commonly used in the literature for these age groups.

RESULTS

A total of 203 patients were included in our study. The Alvarado scoring system yielded the most accurate results for group 1, whereas the Fenyo-Linberg scoring system was the most accurate system for group 2 and the Eskelinen scoring system for group 3.

CONCLUSION

Age should be considered as a major parameter during the selection of the scoring system to be applied for patients with prediagnosis of acute appendicitis. Our study revealed the Alvarado and the Fenyo-Lindberg scoring systems as the most accurate systems for the differential diagnosis of appendicitis in the 18-45 and 46-65 years age groups, respectively. Although we found the Eskelinen scoring system as the most accurate one in the >65 years age group, the confidence intervals indicated that it may not be appropriate for use alone in this group.

A study of patient-reported pain during bone marrow aspiration and biopsy using local anesthesia alone compared with local anesthesia with intravenous midazolam coadministration at a tertiary academic hospital in South Africa

INTRODUCTION

During the bone marrow aspiration and biopsy (BMAB) procedure, patients report pain of widely variable intensity. There is limited literature on the factors associated with the pain. The use of local anesthesia (LA) only is still widespread although it does not abolish the pain. Midazolam is the most commonly used benzodiazepine for conscious sedation. Our center introduced universal midazolam sedation unless there is a contraindication to its use, 4 years ago. This study assessed the impact of the universal use of intravenous midazolam for BMAB compared to use of LA only. The factors associated with the pain of BMAB, were analyzed.

METHODS

A retrospective cross-sectional study was performed on adult patients who had a BMAB procedure from July 1, 2018 to March 30, 2019. A questionnaire incorporating a visual analog pain scale, was used for data collection.

RESULTS

A total of 182 BMAB procedures were included in the study. Pain was reported in all procedures performed under LA and only in 29.1% of procedures performed with midazolam. Age, sex, race, level of education, body mass index (BMI), indication and diagnosis had no influence on pain. Patients who had previous BMAB experienced less pain. Experience of operator had a significant effect on pain. Midazolam dose showed a negative correlation with pain.

CONCLUSION

LA only is not enough to abolish pain of BMAB. Midazolam conscious sedation used with LA reduces pain to acceptable levels. Patients with previous experience of BMAB under midazolam premedication reported less pain. Furthermore, the experience of operator reduced the pain significantly.

The neurobiology of social stress resulting from Racism: Implications for pain disparities among racialized minorities

Extant literature posits that humans experience two types of threat: physical threat and social threat. While describing pain as "physical" or "social" can be helpful for understanding pain origins (i.e., broken bone versus lost relationship), this dichotomy is largely artificial and not particularly helpful for understanding how the human brain experiences pain. One real world example of social exclusion and rejection that is threatening and likely to bring about significant stress is racism. Racism is a system of beliefs, practices, and policies that operates to disadvantage racialized minorities while providing advantage to those with historical power, particularly White people in the United States and most other Western nations. The objective of this Mini-Review is to present evidence in support of the argument that racism promotes physical pain in racialized minorities, which in turn promotes chronic pain disparities. First, we provide a theoretical framework describing how racism is a potent stressor that affects the health and well-being of racialized minorities. We will then address the neurobiological underpinnings linking racism to social threat, as well as that linking social threats and physical pain. Finally, we will discuss how the perception of social threat brought about by racism may undermine pain management efforts.

The Impact of Primary Language Spoken on the Pain Experience of Children With Cancer

The purpose of the current prospective cohort study was to determine if acculturation, measured by primary language spoken, impacts the pain response of children being treated for cancer during an experimental pain task. Sixty-seven Spanish-speaking and English-speaking children ages 6 to 18 years being treated for cancer provided ratings of pain and upset severity during the completion of the cold pressor task (CPT). One week following the CPT, participants provided their recollection of average pain and upset during the CPT. Repeated measures analysis of variance revealed Spanish-speaking children reported significantly higher pain (F1,64=5.58, P=0.02) and upset (F1,64=7.69, P=0.007) ratings during the CPT compared with English-speaking children. Also, Spanish-speaking children were over 4 times as likely to remove their hands from the water before the CPT 4-minute uninformed ceiling compared with English-speaking children (P=0.002). These findings suggest that cultural and contextual factors, including the level of acculturation, are important considerations in the assessment and management of pain in children with cancer. Future research should continue to examine the mechanisms underlying the association between acculturation and the symptom experience for children receiving treatment for cancer.

Dysmenorrhea and associated symptoms in Ethiopia: A systematic review and meta-analysis

Introduction:

Dysmenorrhea is the most common gynecologic compliant and reproductive health problem among adolescents, young, and reproductive age group. Dysmenorrhea has psychological, physical, and behavioral impact on adolescent girls in different regions.

Objective:

This systematic review and meta-analysis aimed to assess the overall prevalence of dysmenorrhea, its pain intensity and associated symptoms in Ethiopia and compare with other countries.

Methods:

Literatures from PubMed, MEDLINE, EMABSE, CINHAL, SCOPUS, Hinari, Africa journals, and Google scholar were retrieved. Eligible cross-sectional studies were included for meta-analysis. I2 statistics was calculated to check heterogeneity. Subgroup analysis based on outcome of interest was performed. Sensitivity analysis was undertaken to examine the level of heterogeneity.

Results:

The prevalence of overall and primary dysmenorrhea in Ethiopia was 72% (95%CI 68–77) and 72.27% (95%CI 69.8–75.33) respectively. Back pain 56.62% (95%CI 46.68–66.57) and fatigue 51.51% (95%CI 40.08–62.94) were more common than headache 29.15% (95%CI 18.16–40.14) whereas moderate pain 41.03% (95%CI 33.98–48.07) was more common than mild 31.83% (95%CI 21.61–42.05) and severe pain intensity 21.57% (95%CI 14.24–28.89). The prevalence between small and large samples, Northern and South/West Ethiopia, and school girls and university students were nearly similar. Positive family history (OR = 4.05; 95%CI 3.15–5.20), early menarche (OR = 2.91; 95%CI 2.00–4.24) and irregular monthly menstrual cycle (OR = 1.87, 95%CI 1.23–2.84) were the predictors of dysmenorrhea.

Conclusion:

Compared with other countries, the prevalence of dysmenorrhea in Ethiopia is moderate, presenting as mainly back pain and fatigue with moderate pain intensity. Positive family history, early menarche, and irregular menstrual cycle are the positive contributing factors.

Lack of Effects of the Presence of a Dog on Pain Perception in Healthy Participants-A Randomized Controlled Trial

Animal-assisted interventions (AAIs) have been shown to be effective in the treatment of pain. Studies suggest that relationships with animals can have comparable qualities to relationships with humans and that this enables animals to provide social support. Further, the presence of an animal can strengthen the therapeutic alliance between patients and treatment providers. This suggests that the analgesic effects of AAI might be mediated by social support from an animal or by strengthening the alliance between the patient and the treatment provider. To test these assumptions, we examined the effects of the presence of a dog on experimentally induced pain in a pain assessment and a pain therapy context. Hundred thirty-two healthy participants were randomly assigned to the conditions “pain,” “pain + dog,” “pain + placebo,” or “pain + placebo + dog.” We collected baseline and posttreatment measurements of heat-pain tolerance and the heat-pain threshold and of the corresponding subjective ratings of heat-pain intensity and unpleasantness as well as of participants' perceptions of the study investigator. The primary outcome was heat-pain tolerance. The presence of the dog did not influence the primary outcome (“pain” vs. “pain + dog”: difference = 0.04, CI = −0.66 to 0.74, p = 0.905; “pain + placebo” vs. “pain + placebo + dog”: difference = 0.43, CI = −0.02 to 0.88, p = 0.059). Participants did also not perceive the study investigator to be more trustworthy in the presence of the dog (“pain” vs. “pain + dog”: difference = 0.10, CI = −0.67 to 0.87, p = 0.796; “pain + placebo” vs. “pain + placebo + dog”: difference = 0.11, CI = −0.43 to 0.64, p = 0.695). The results indicate that the mere presence of a dog does not contribute to pain reduction and that the analgesic effects of AAI that previous studies have found is not replicated in our study as AAI did not increase perceived social support and had no effect on the alliance between the participant and the treatment provider. We assume that the animal most likely needs to be an integrated and plausible part of the treatment rationale so that participants are able to form a treatment-response expectation toward AAI.

Clinical Trial Registration: This study was preregistered as a clinical trial on www.clinicaltrials.gov (Identifier: NCT0389814).

Racial Differences in Pain, Nutrition, and Oxidative Stress

Investigating the disproportionate rates of chronic pain and their related comorbidities between Black and non-Hispanic White (White) individuals is a growing area of interest, both in the healthcare community and in general society. Researchers have identified racial differences in chronic pain prevalence and severity, but still very little is known about the mechanisms underlying them. Current explanations for these differences have primarily focused on socioeconomic status and unequal healthcare between races as causal factors. Whereas these factors are informative, a racial gap still exists between Black and White individuals when these factors are controlled for. One potential cause of this racial gap in chronic pain is the differences in nutrition and dietary intake between groups. Certain foods play a key role in the inflammatory and oxidative stress pathways in the human body and could potentially influence the severity of the pain experience. Here, we review the previous literature on the surrounding topics and propose a potential mechanism to explain racial differences in the chronic pain population, based on established racial differences in diet and oxidative stress.

Chronic Pain Severity and Sociodemographics: An Evaluation of the Neurobiological Interface

Chronic pain is variably associated with brain structure. Phenotyping based on pain severity may address inconsistencies. Sociodemographic groups also differ in the experience of chronic pain severity. Whether differences by chronic pain severity and/or sociodemographic groups are indicated in pain-related areas of the brain is unknown. Relations between 2 measures of chronic pain severity and brain structure via T1-weighted MRI were investigated and sociodemographic group differences explored. The observational study included 142 community-dwelling (68 non-Hispanic Black [NHB] and 74 non-Hispanic White [NHW]) adults with/at risk for knee osteoarthritis. Relationships between chronic pain severity, sociodemographic groups, and a priori selected brain structures (postcentral gyrus, insula, medial orbitofrontal, anterior cingulate, rostral middle frontal gyrus, hippocampus, amygdala, thalamus) were explored. Chronic pain severity associated with cortical thickness. NHB participants reported lower sociodemographic protective factors and greater clinical pain compared to NHWs who reported higher sociodemographic protective factors and lower clinical pain. Greater chronic pain severity was associated with smaller amygdala volumes in the NHB group and larger amygdala volumes in the NHW group. Brain structure by chronic pain stage differed between and within sociodemographic groups. Overall, chronic pain severity and sociodemographic factors are associated with pain-related brain structures. Our findings highlight the importance of further investigating social and environmental contributions in the experience of chronic pain to unravel the complex array of factors contributing to disparities. PERSPECTIVE: The study presents data demonstrating structural brain relationships with clinical pain severity, characteristic pain intensity and chronic pain stage, differ by sociodemographic groups. Findings yield insights into potential sources of previous inconsistent pain-brain relationships and highlights the need for future investigations to address social and environmental factors in chronic pain disparities research.

Play the Pain: A Digital Strategy for Play-Oriented Research and Action

The value of understanding patients' illness experience and social contexts for advancing medicine and clinical care is widely acknowledged. However, methodologies for rigorous and inclusive data gathering and integrative analysis of biomedical, cultural, and social factors are limited. In this paper, we propose a digital strategy for large-scale qualitative health research, using play (as a state of being, a communication mode or context, and a set of imaginative, expressive, and game-like activities) as a research method for recursive learning and action planning. Our proposal builds on Gregory Bateson's cybernetic approach to knowledge production. Using chronic pain as an example, we show how pragmatic, structural and cultural constraints that define the relationship of patients to the healthcare system can give rise to conflicted messaging that impedes inclusive health research. We then review existing literature to illustrate how different types of play including games, chatbots, virtual worlds, and creative art making can contribute to research in chronic pain. Inspired by Frederick Steier's application of Bateson's theory to designing a science museum, we propose DiSPORA (Digital Strategy for Play-Oriented Research and Action), a virtual citizen science laboratory which provides a framework for delivering health information, tools for play-based experimentation, and data collection capacity, but is flexible in allowing participants to choose the mode and the extent of their interaction. Combined with other data management platforms used in epidemiological studies of neuropsychiatric illness, DiSPORA offers a tool for large-scale qualitative research, digital phenotyping, and advancing personalized medicine.

Racial and weight discrimination associations with pain intensity and pain interference in an ethnically diverse sample of adults with obesity: a baseline analysis of the clustered randomized-controlled clinical trial the goals for eating and moving (GEM) study

BACKGROUND

Everyday experiences with racial (RD) and weight discrimination (WD) are risk factors for chronic pain in ethnically diverse adults with obesity. However, the individual or combined effects of RD and WD on pain in adults with obesity is not well understood. There are gender differences and sexual dimorphisms in nociception and pain, but the effect of gender on relationships between RD, WD, and pain outcomes in ethnically diverse adults with obesity is unclear. Thus, the purposes of this study were to: 1) examine whether RD and WD are associated with pain intensity and interference, and 2) explore gender as a moderator of the associations between RD, WD, and pain.

METHODS

This is a baseline data analysis from a randomized, controlled clinical trial of a lifestyle weight-management intervention. Eligible participants were English or Spanish-speaking (ages 18-69 years) and had either a body mass index of ≥30 kg/m2 or ≥ 25 kg/m2 with weight-related comorbidity. RD and WD were measured using questions derived from the Experiences of Discrimination questionnaire (EOD). Pain interference and intensity were measured using the PROMIS 29 adult profile V2.1. Linear regression models were performed to determine the associations between WD, RD, gender, and pain outcomes.

RESULTS

Participants (n = 483) reported mild pain interference (T-score: 52.65 ± 10.29) and moderate pain intensity (4.23 ± 3.15). RD was more strongly associated with pain interference in women (b = .47, SE = .08, p < 001), compared to men (b = .14, SE = .07, p = .06). Also, there were no significant interaction effects between RD and gender on pain intensity, or between WD and gender on pain interference or pain intensity.

CONCLUSIONS

Pain is highly prevalent in adults with obesity, and is impacted by the frequencies of experiences with RD and WD. Further, discrimination against adults with obesity and chronic pain could exacerbate existing racial disparities in pain and weight management. Asking ethnically diverse adults with obesity about their pain and their experiences of RD and WD could help clinicians make culturally informed assessment and intervention decisions that address barriers to pain relief and weight loss.

TRIAL REGISTRATION

NCT03006328.

Use of likelihood estimates for variances for the design and evaluation of multiregional clinical trials with heterogeneous variances

Globalized drug development studies, such as multiregional clinical trials (MRCTs), have attracted much attention due to their ability to expedite drug development and shorten the time lag of drug release. While observing the overall effect of a new drug, the region-specific effects to support drug registration in constituent regions can also be evaluated. Several challenges arise in conducting MRCTs, such as the heterogeneity in the variability of the primary endpoint across regions. However, most of the existing statistical methods assume a common variability, which may not be valid in practice due to differences across regions (eg, diversities in ethnicity or disparities in medical culture/practice). We present a statistical method for the design and evaluation of MRCTs to consider the heterogeneous variability across regions. We assessed the overall sample size requirement and addressed the region-specific sample size determination to establish the consistency of treatment effects between the specific region and the entire group. We demonstrate the proposed approach with numerical examples.

Ethnic disparities in pain processing among healthy adults: μ-opioid receptor binding potential as a putative mechanism

Although ethnic differences in pain perception are well documented, the underlying mechanism for these outcomes has not been established. µ-opioid receptor (MOR) function might contribute to this disparity, given that MORs play a key role in pain sensitivity and modulation. However, no study has characterized ethnic differences in MOR physiology. This study sought to address this knowledge gap by examining differences in µ-selective agonist binding potential (BPND; [C]-Carfentanil) between 27 non-Hispanic black (NHB) and 27 demographically similar, non-Hispanic white participants. Participants completed questionnaires and two 90-minute high-resolution research tomograph positron emission tomography (PET) imaging sessions. During PET imaging, a capsaicin or control cream was applied to individuals' arms, and pain ratings were collected. Bonferroni-corrected PET volumes of interest analyses revealed significantly greater [C]-Carfentanil BPND among NHB participants in bilateral ventral striatum ([left]: F1,52 = 16.38, P < 0.001; [right]: F1,52 = 21.76, P < 0.001), bilateral dorsolateral prefrontal cortex ([left] F1,52 = 17.3, P < 0.001; [right]: F1,52 = 14.17, P < 0.001), bilateral subgenual anterior cingulate cortex ([left]: F1,52 = 10.4, P = 0.002; [right]: F1,52 = 12.91, P = 0.001), and right insula (F1,52 = 11.0, P = 0.002). However, there were no significant main effects of condition or ethnicity × condition interaction effects across models, likely attributable to individual variability in the direction of change within groups. BPND values were significantly correlated with pain ratings collected during the capsaicin condition (r range = 0.34-0.46, P range = 0.01-0.001). Results suggest that NHB individuals might have generally greater unoccupied MOR density than non-Hispanic white peers. Findings have implications for physiological differences underlying ethnicity-related pain disparities. If replicated, these results further emphasize the need for tailored treatments in historically underserved populations.

The Adaptation of Pain Assessment Tools from High-Income to Low- and Middle-Income Countries: Psychometric Properties of a Set of Chronic Pain Questionnaires in Mongolian and New Zealand Patient Samples

OBJECTIVE

Chronic pain is a leading cause of disability in low- and middle-income countries; however, pain assessment tools have generally been developed and validated in high-income countries. This study examines the psychometric properties of a set of translated pain (and distress) questionnaires in Mongolia and documents the characteristics of people seeking treatment for chronic pain in Mongolia, compared with those in New Zealand, which is representative of high-income countries.

DESIGN

Cross-sectional, observational.

SETTING

Hospital-based pain treatment centers in New Zealand and Mongolia.

SUBJECTS

People seeking treatment for chronic pain in Mongolia (N = 142) and New Zealand (N = 159).

METHODS

The Brief Pain Inventory, the Depression Anxiety Stress Scale-21, the Pain Catastrophizing Scale, and the Pain Self-Efficacy Questionnaire were translated into Mongolian and administered to patients attending a hospital-based pain service. Questionnaires that were completed by patients in New Zealand were used for comparisons. Internal reliability, convergent validity, and factor structure were assessed in both groups.

RESULTS

Patients in Mongolia were older and reported lower pain intensity, interference, and distress and higher pain self-efficacy than those in New Zealand. The translated questionnaires had good internal consistencies, and the relationships between pain variables were similar across both groups. The factor structure for the Pain Catastrophizing Scale was consistent across both groups, but this was not the case for the Brief Pain Inventory or the Depression Anxiety Stress Scale-21.

CONCLUSIONS

Findings indicate that some pain outcome measures may be appropriate for use in Mongolia and should be investigated in other low- and middle-income countries.

Differences in Psychosocial Factors and Experimental Pain Sensitivity between Hispanics and non-Hispanic Whites from the U.S.-Mexico Border

PURPOSE

Research suggests that ethnicity is a predictor of pain-related outcomes; however, studies comparing the differences in experimental pain sensitivity between Hispanics and non-Hispanic Whites (NHW) are scarce. This study investigated these differences between Hispanics and NHW from the U.S- Mexico border.

METHODS

Fifty-eight healthy subjects completed the survey packet, which included a demographic and a psychosocial factors questionnaire. Participants underwent quantitative sensory testing which included heat pain threshold, heat pain tolerance, Suprathreshold Heat Pain Response (SHPR), and Conditioned Pain Modulation (CPM). SHPR was induced by repeated thermal stimuli in both thenar eminences. CPM was assessed using SHPR as the experimental stimulus, and cold pressor task as the conditioning stimulus.

RESULTS

Analyses showed significant differences in experimental pain measures believed to be representative of facilitatory pain processing including SHPR, and heat pain threshold, where Hispanics reported significantly higher pain ratings than NHW. Hispanics also reported higher levels of ethnic identity and acculturation. However, these factors were not significantly associated with experimental pain sensitivity.

CONCLUSION

The experimental pain sensitivity and psychosocial factors included in this study differed by ethnic group, where Hispanics reported significantly higher pain ratings, when compared to NHW. However, ethnic identity and acculturation were not associated with these pain-related outcomes. Overall, enhanced understanding by clinicians of pain sensitivity and disparities in the pain experience between ethnic groups allows for increased cultural sensitivity and can be used to optimize pain treatment on an individual-by-individual basis.

Racial/Ethnic Differences in Staff-Assessed Pain Behaviors Among Newly Admitted Nursing Home Residents

CONTEXT

Nonverbal pain behaviors are effective indicators of pain among persons who have difficulty communicating. In nursing homes, racial/ethnic differences in self-reported pain and pain management have been documented.

OBJECTIVES

We sought to examine racial/ethnic differences in nonverbal pain behaviors and pain management among residents with staff-assessed pain.

METHODS

We used the U.S. national Minimum Data Set 3.0 and identified 994,510 newly admitted nursing home residents for whom staff evaluated pain behaviors and pain treatments between 2010 and 2016. Adjusted prevalence ratios (aPRs) and 95% CIs estimated using robust Poisson models compared pain behaviors and treatments across racial/ethnic groups.

RESULTS

Vocal complaints were most commonly recorded (18.3% non-Hispanic black residents, 19.3% of Hispanic residents, and 30.3% of non-Hispanic white residents). Documentation of pain behaviors was less frequent among non-Hispanic black and Hispanic residents than non-Hispanic white residents (e.g., vocal complaints: aPR_Black: 0.76; 95% CI: 0.73-0.78; with similar estimates for other pain behaviors). Non-Hispanic blacks (47.3%) and Hispanics (48.6%) were less likely to receive any type of pharmacologic pain intervention compared with non-Hispanic white residents (59.3%) (aPR_Black: 0.87; 95% CI: 0.86-0.88; aPR_Hispanics: 0.87; 95% CI: 0.84-0.89).

CONCLUSION

Among residents requiring staff assessment of pain because they are unable to self-report, nursing home staff documented pain and its treatment less often in Non-Hispanic blacks and Hispanics than in non-Hispanic white residents. Studies to understand the role of differences in expression of pain, explicit bias, and implicit bias are needed to inform interventions to reduce disparities in pain documentation and treatment.

Role of VVZ-149, a Novel Analgesic Molecule, in the Affective Component of Pain: Results from an Exploratory Proof-of-Concept Study of Postoperative Pain following Laparoscopic and Robotic-Laparoscopic Gastrectomy

OBJECTIVE

VVZ-149 is a small molecule that both inhibits the glycine transporter type 2 and the serotonin receptor 5 hydroxytryptamine 2 A. In a randomized, parallel-group, and double-blind trial (NCT02844725), we investigated the analgesic efficacy and safety of VVZ-149 Injections, which is under clinical development as a single-use injectable product for treating moderate to severe postoperative pain.

METHODS

Sixty patients undergoing laparoscopic and robotic-laparoscopic gastrectomy were randomly assigned to receive a 10-hour intravenous infusion of VVZ-149 Injections or placebo, initiated approximately 1 hour before completion of surgical suturing. Major outcomes included pain intensity and opioid consumption via patient-controlled analgesia and rescue analgesia provided "as needed." The treatment efficacy of VVZ-149 was further examined in a subpopulation requiring early rescue medication, previously associated with the presence of high levels of preoperative negative affect in a prior Phase 2 study (NCT02489526).

RESULTS

Pain intensity was lower in the VVZ-149 (n = 30) than the placebo group (n = 29), reaching statistical significance at 4 hours post-emergence (P < .05), with a 29.5% reduction in opioid consumption for 24 hours and fewer demands for patient-controlled analgesia. In the rescued subgroup, VVZ-149 further reduced pain intensity (P < .05) with 32.6% less opioid consumption for 24 hours compared to placebo patients.

CONCLUSIONS

VVZ-149 demonstrated effective analgesia with reduced postoperative pain and opioid requirements. Consistent with the results from the previous Phase 2 study, patients with early rescue requirement had greater benefit from VVZ-149, supporting the hypothesis that VVZ-149 may alleviate the affective component of pain and mitigate excessive use of opioids postoperatively.

Risk of depression and anemia in users of hormonal endometriosis treatments: Results from the VIPOS study

OBJECTIVE

Dienogest (DNG) 2 mg (Visanne) was launched for endometriosis treatment in Europe in 2010. The Visanne Post-approval Observational Study (VIPOS) was designed to assess the safety of DNG 2 mg/day compared to other hormonal endometriosis treatments, focusing especially on clinically relevant depression and anemia.

STUDY DESIGN

Large, prospective, non-interventional, active surveillance study in six European countries. Participants were recruited via gynecologists or specialized centers routinely prescribing endometriosis medication. Self-administered questionnaires during study entry and follow-up collected information on baseline characteristics, health status and endometriosis treatment. Patient-reported anemia and depression cases were validated by health care professionals. Inferential statistics were based on Cox proportional hazards models and crude and adjusted hazard ratios (HR) between cohorts were calculated (including 95% confidence intervals [CI]). Adjustment for potential confounding was performed by including predefined prognostic factors as covariates in the Cox models.

RESULTS

Out of 26,430 participants, 11.4% used DNG, 12.8% used other approved endometriosis medications (OAED) and 75.7% used hormonal treatments not approved but frequently used for endometriosis treatment (NAED). At baseline, DNG users more frequently reported a surgically confirmed endometriosis diagnosis, severe endometriosis-associated pain and a history of depression, compared to the other cohorts. Baseline characteristics showed large inter-country variability. Overall, the number of confirmed anemia and depression events were substantially lower than expected. The adjusted HRs for anemia were 1.1 (95% CI, 0.4-2.6) for DNG vs OAED and 1.3 (95% CI, 0.7-2.4) for DNG vs NAED. The adjusted HRs for new or worsening depression were 1.8 (95% CI, 0.3-9.4) for DNG vs OAED and 1.5 (95% CI, 0.8-2.8) for DNG vs NAED.

CONCLUSION

The main limitations encountered (low number of confirmed events and considerable inter-country variability) made a robust statistical analysis and a solid interpretation of the results challenging. However, no safety signal regarding anemia for DNG users could be detected, whereas a slight increase in depression risk cannot be excluded but might be explained by baseline severity of endometriosis or unknown country-specific confounding variables. VIPOS reflected routine use of hormonal endometriosis medications and provided real-world insights into endometriosis management in Europe.

Ethnic Differences in Experimental Pain Responses Following a Paired Verbal Suggestion With Saline Infusion: A Quasiexperimental Study

BACKGROUND

Ethnic differences in placebo and nocebo responses are an important, yet underresearched, patient factor that might contribute to treatment disparities.

PURPOSE

The purpose of this study was to examine ethnic differences in pain trajectories following a verbal suggestion paired with a masked, inert substance (i.e., saline).

METHODS

Using a quasiexperimental design, we examined differences between 21 non-Hispanic Black (NHB) participants and 20 non-Hispanic White (NHW) participants in capsaicin-related pain rating trajectories following a nondirectional verbal suggestion + saline infusion. All participants were told that the substance would "either increase pain sensation, decrease it, or leave it unchanged." A spline mixed model was used to quantify the interaction of ethnicity and time on ratings.

RESULTS

There was a significant Ethnicity × Time interaction effect (β = -0.28, p = .002); NHB individuals reported significantly greater increases in pain following, but not before, the verbal suggestion + saline infusion. Sensitivity analyses showed no change in primary results based on differences in education level, general pain sensitivity, or condition order.

CONCLUSIONS

The present results showed ethnic differences in pain response trajectories following a verbal suggestion + saline infusion and suggest that future research rigorously examining possible ethnic differences in placebo/nocebo responses is warranted.

The Effects of Racial/Ethnic Minority Status on Sleep, Mood Disturbance, and Depression in People with Fibromyalgia

Purpose

Fibromyalgia syndrome (FMS) is a chronic musculoskeletal pain disorder that is characterized by persistent and widespread pain. FMS has been associated with sleep disturbance, mood disorders and depression. Racial/ethnic minorities are less likely to receive a diagnosis of FMS than White individuals. Although mood disorders and depression are prevalent among racial/ethnic minority groups, researchers have not examined whether there are differences between racial/ethnic minorities and White individuals with FMS.

Participants and Methods

The participants were 600 people who were 18 years of age or older and who had a physician's diagnosis of FMS, which was confirmed using the 1990 American College of Rheumatology criteria. Most participants were female (95.5%) and White (85.0%). Sleep disturbance was assessed using the Pittsburgh Sleep Quality Index (PSQI), mood disturbance was assessed using the Profile of Mood States (POMS), and depression was assessed via the Center for Epidemiological Studies Depression Scale (CES-D).

Results

Racial/ethnic minorities reported significantly greater levels of sleep disturbance, significantly greater levels of mood disturbance, and had significantly greater levels of depression than White participants. However, racial/ethnic minorities had significantly greater reductions in mood disturbance over the one-year period than White participants.

Conclusion

Overall, the findings from the present study indicated that racial/ethnic minorities had "worse" physical and psychological outcomes than White participants.

Assessing peripheral fibers, pain sensitivity, central sensitization, and descending inhibition in Native Americans: main findings from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) have a higher prevalence of chronic pain than other U.S. racial/ethnic groups, but there have been few attempts to understand the mechanisms of this pain disparity. This study used a comprehensive battery of laboratory tasks to assess peripheral fiber function (cool/warm detection thresholds), pain sensitivity (eg, thresholds/tolerances), central sensitization (eg, temporal summation), and pain inhibition (conditioned pain modulation) in healthy, pain-free adults (N = 155 NAs, N = 150 non-Hispanic Whites [NHWs]). Multiple pain stimulus modalities were used (eg, cold, heat, pressure, ischemic, and electric), and subjective (eg, pain ratings and pain tolerance) and physiological (eg, nociceptive flexion reflex) outcomes were measured. There were no group differences on any measure, except that NAs had lower cold-pressor pain thresholds and tolerances, indicating greater pain sensitivity than NHWs. These findings suggest that there are no group differences between healthy NAs and NHWs on peripheral fiber function, central sensitization, or central pain inhibition, but NAs may have greater sensitivity to cold pain. Future studies are needed to examine potential within-group factors that might contribute to NA pain risk.

Pain-related anxiety promotes pronociceptive processes in Native Americans: bootstrapped mediation analyses from the Oklahoma Study of Native American Pain Risk

INTRODUCTION

Evidence suggests Native Americans (NAs) experience higher rates of chronic pain than the general US population, but the mechanisms contributing to this disparity are poorly understood. Recently, we conducted a study of healthy, pain-free NAs (n = 155), and non-Hispanic whites (NHWs, n = 150) to address this issue and found little evidence that NAs and NHWs differ in pain processing (assessed from multiple quantitative sensory tests). However, NAs reported higher levels of pain-related anxiety during many of the tasks.

OBJECTIVE

The current study is a secondary analysis of those data to examine whether pain-related anxiety could promote pronociceptive processes in NAs to put them at chronic pain risk.

METHODS

Bootstrapped indirect effect tests were conducted to examine whether pain-related anxiety mediated the relationships between race (NHW vs NA) and measures of pain tolerance (electric, heat, ischemia, and cold pressor), temporal summation of pain and the nociceptive flexion reflex (NFR), and conditioned pain modulation of pain/NFR.

RESULTS

Pain-related anxiety mediated the relationships between NA race and pain tolerance and conditioned pain modulation of NFR. Exploratory analyses failed to show that race moderated relationships between pain-related anxiety and pain outcomes.

CONCLUSION

These findings imply that pain-related anxiety is not a unique mechanism of pain risk for NAs, but that the greater tendency to experience pain-related anxiety by NAs impairs their ability to engage descending inhibition of spinal nociception and decreases their pain tolerance (more so than NHWs). Thus, pain-related anxiety may promote pronociceptive processes in NAs to place them at risk for future chronic pain.

'Sirim' (Cold) Pain as a Common Symptom in Korean Patients with Clinically Suspected Small-Fiber Neuropathy

Background and Purpose

Diagnosing small-fiber neuropathy (SFN) is challenging because there is no gold-standard test and few diagnostic tests. This study investigated the clinical symptom profile and its associations with the results of quantitative sensory testing (QST) and the quantitative sudomotor axon reflex test (QSART) as well as the quality of life (QOL) in patients with clinically suspected SFN.

Methods

This study involved 63 patients with clinically suspected length-dependent SFN. Assessments were performed using QST, QSART, SFN Symptoms Inventory Questionnaire, Neuropathic Pain Symptom Inventory, ‘Sirim’ frequency and ‘Sirim’ (cold) pain severity, and 36-item Short-Form Health Survey. Multiple logistic and linear regression analyses were performed to predict risk factors for QST or QSART abnormalities and QOL, respectively.

Results

‘Sirim’ and ‘Sirim’ pain was the most-common (84%) and the most-severe complaint (mean score of 6.3 on a numerical rating scale ranging from 0 to 10) in patients with clinically suspected SFN. The findings of QST [cold detection threshold (CDT)] and QSART were abnormal in 71% (n=45/57) and 62% (n=39/56) of the patients, respectively. An abnormal CDT was correlated with more-severe stabbing pain (odds ratio=2.23, 95% CI=1.02–4.87, p=0.045). Restless-leg symptoms (β=−7.077) and pressure-evoked pain (β=−5.034) were independent predictors of the physical aspects of QOL.

Conclusions

‘Sirim’ pain, similar to cold pain, should be considered a major neuropathic pain in SFN. Among pain characteristics, stabbing pain of a spontaneous paroxysmal nature may be more pronounced in the setting of dysfunctional Aδ fibers with functional autonomic C fibers.

The Clinical Relevance of Pain Severity Changes: Is There Any Difference Between Asian and Caucasian Patients With Osteoarthritis Pain?

The objective of the present analysis was to determine whether changes in Brief Pain Inventory (BPI) average pain scores by patient global impression of improvement (PGI‐I) category and the cut‐off for clinically important difference (CID) were different between Asian and Caucasian patients with chronic pain due to osteoarthritis. This analysis used data from 3 (Caucasian) and 2 (Asian) randomized, placebo‐controlled, 10‐ to 14‐week duloxetine studies for the treatment of patients ≥40 years of age with osteoarthritis pain. The receiver operating characteristic (ROC) analysis was used to characterize the association between changes in BPI average pain scores and PGI‐I levels at study endpoint. The CID was characterized by PGI‐I, and the cut‐off point for CID in BPI average pain scores was determined by the intersection of a 45‐degree tangent line with each ROC curve. Data from 668 Asian and 868 Caucasian patients were available for analysis. Baseline BPI average pain ratings including worst and least pain were comparable between Asians and Caucasians. Ratings for percentage change from baseline to endpoint for BPI average pain scores in Asian patients and Caucasian patients were similar across the 7 PGI‐I categories, regardless of age, gender, study, and treatment. The ROC analysis results of cut‐off points in BPI average pain scores demonstrated the raw change cut‐off was −3.0, and percentage change cut‐off was −40% for both Asian and Caucasian patients. Overall, the present analysis concludes changes in BPI average pain scores by PGI‐I category and the cut‐off for CID were similar for Asian and Caucasian patients with chronic pain due to osteoarthritis.

Sensory, Affective, and Catastrophizing Reactions to Multiple Stimulus Modalities: Results from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) have a higher prevalence of chronic pain than any other U.S. racial/ethnic group; however, little is known about the mechanisms for this pain disparity. This study used quantitative sensory testing to assess pain experience in healthy, pain-free adults (n = 137 NAs (87 female), n = 145 non-Hispanic whites (NHW; 68 female)) after painful electric, heat, cold, ischemic, and pressure stimuli. After each stimulus, ratings of pain intensity, sensory pain, affective pain, pain-related anxiety, and situation-specific pain catastrophizing were assessed. The results suggested that NAs reported greater sensory pain in response to suprathreshold electric and heat stimuli, greater pain-related anxiety to heat and ischemic stimuli, and more catastrophic thoughts in response to electric and heat stimuli. Sex differences were also noted; however, with the exception of catastrophic thoughts to cold, these finding were not moderated by race/ethnicity. Together, findings suggest NAs experience heightened sensory, anxiety, and catastrophizing reactions to painful stimuli. This could place NAs at risk for future chronic pain and could ultimately lead to a vicious cycle that maintains pain (eg, pain → anxiety/catastrophizing → pain). PERSPECTIVE: NAs experienced heightened sensory, anxiety, and catastrophizing reactions in response to multiple pain stimuli. Given the potential for anxiety and catastrophic thoughts to amplify pain, this characteristic may place them at risk for pain disorders and could lead to a vicious cycle that maintains pain.

An experimental investigation of the relationships among race, prayer, and pain

Background and aims Compared to White individuals, Black individuals demonstrate a lower pain tolerance. Research suggests that differences in pain coping strategies, such as prayer, may mediate this race difference. However, previous research has been cross-sectional and has not determined whether prayer in and of itself or rather the passive nature of prayer is driving the effects on pain tolerance. The aim of this study was to clarify the relationships among race, prayer (both active and passive), and pain tolerance. Methods We randomly assigned 208 pain-free participants (47% Black, 53% White) to one of three groups: active prayer ("God, help me endure the pain"), passive prayer ("God, take the pain away"), or no prayer ("The sky is blue"). Participants first completed a series of questionnaires including the Duke University Religion Index, the Coping Strategies Questionnaire-Revised (CSQ-R), and the Pain Catastrophizing Scale. Participants were then instructed to repeat a specified prayer or distractor coping statement while undergoing a cold pressor task. Cold pain tolerance was measured by the number of seconds that had elapsed while the participant's hand remained in the cold water bath (maximum 180 s). Results Results of independent samples t-tests indicated that Black participants scored higher on the CSQ-R prayer/hoping subscale. However, there were no race differences among other coping strategies, religiosity, or catastrophizing. Results of a 2 (Race: White vs. Black)×3 (Prayer: active vs. passive vs. no prayer) ANCOVA controlling for a general tendency to pray and catastrophizing in response to prayer indicated a main effect of prayer that approached significance (p=0.06). Pairwise comparisons indicated that those in the active prayer condition demonstrated greater pain tolerance than those in the passive (p=0.06) and no prayer (p=0.03) conditions. Those in the passive and no prayer distractor conditions did not significantly differ (p=0.70). There was also a trending main effect of race [p=0.08], with White participants demonstrating greater pain tolerance than Black participants. Conclusions Taken together, these results indicate that Black participants demonstrated a lower pain tolerance than White participants, and those in the active prayer condition demonstrated greater tolerance than those in the passive and no prayer conditions. Furthermore, Black participants in the passive prayer group demonstrated the lowest pain tolerance, while White participants in the active prayer group exhibited the greatest tolerance. Results of this study suggest that passive prayer, like other passive coping strategies, may be related to lower pain tolerance and thus poorer pain outcomes, perhaps especially for Black individuals. On the other hand, results suggest active prayer is associated with greater pain tolerance, especially for White individuals. Implications These results suggest that understanding the influence of prayer on pain may require differentiation between active versus passive prayer strategies. Like other active coping strategies for pain, active prayer may facilitate self-management of pain and thus enhance pain outcomes independent of race. Psychosocial interventions may help religiously-oriented individuals, regardless of race, cultivate a more active style of prayer to improve their quality of life.

Can aberrant spinal nociception be a marker of chronicity of pain in fibromyalgia syndrome?

Pain sensitivity is a recognized feature of fibromyalgia syndrome (FMS) but the contribution of spinal nociceptive circuitry to this phenomenon is unknown. Therefore, the objectives were to study the changes in spinal nociception i.e. nociceptive flexion reflex (NFR) in patients with FMS and to investigate correlation if any, between NFR threshold, pain duration and tender points in FMS. One hundred and three patients with FMS and 74 healthy volunteers participated in the study. To record NFR, sural nerve was stimulated in the retro malleolar region and the reflex response was recorded from the short head of biceps femoris muscle. NFR was elicited at significantly lower [21.0(18.0-25.0)V] thresholds in FMS group when compared to healthy subjects [30.0(24.75-35.0)V; p = 0.001] indicating hyperalgesic response to electrocutaneous stimulation in FMS patients. The latency and other parameters of NFR were comparable in both the groups. No significant correlation was found among NFR threshold and pain duration or tender points. On the basis of results of present study, it may be concluded that the functional deficit of the spinal nociceptive system can contribute to hyperalgesia in FMS. This is first study that correlates a marker of central hyper-excitability (NFR threshold) with clinical symptoms (pain duration and tender points) of FMS.

Racial/ethnic differences in experimental pain sensitivity and associated factors - Cardiovascular responsiveness and psychological status

This study evaluated the contributions of psychological status and cardiovascular responsiveness to racial/ethnic differences in experimental pain sensitivity. The baseline measures of 3,159 healthy individuals-non-Hispanic white (NHW): 1,637, African-American (AA): 1,012, Asian: 299, and Hispanic: 211-from the OPPERA prospective cohort study were used. Cardiovascular responsiveness measures and psychological status were included in structural equation modeling based mediation analyses. Pain catastrophizing was a significant mediator for the associations between race/ethnicity and heat pain tolerance, heat pain ratings, heat pain aftersensations, mechanical cutaneous pain ratings and aftersensations, and mechanical cutaneous pain temporal summation for both Asians and AAs compared to NHWs. HR/MAP index showed a significant inconsistent (mitigating) mediating effect on the association between race/ethnicity (AAs vs. NHWs) and heat pain tolerance. Similarly, coping inconsistently mediated the association between race/ethnicity and mechanical cutaneous pain temporal summation in both AAs and Asians, compared to NHWs. The factor encompassing depression, anxiety, and stress was a significant mediator for the associations between race/ethnicity (Asians vs. NHWs) and heat pain aftersensations. Thus, while pain catastrophizing mediated racial/ethnic differences in many of the QST measures, the psychological and cardiovascular mediators were distinctly restrictive, signifying multiple independent mechanisms in racial/ethnic differences in pain.

Do Sleep and Psychological Distress Mediate the Association Between Neighborhood Factors and Pain?

OBJECTIVE

Pain affects millions of American adults. However, individuals from socioeconomically disadvantaged groups experience higher rates of pain, and individuals from racial/ethnic minorities report greater pain severity and pain-related disability. Some studies find an association between neighborhood socioeconomic status and pain. The present study aimed to further understand the association between neighborhood disadvantage and pain, including the role of objective (e.g., crime rates) and subjective neighborhood characteristics (e.g., perceived safety, neighborhood satisfaction), and to examine sleep and psychological distress as potential mediators of these associations.

METHODS

The sample included 820 participants from two predominantly African American socioeconomically disadvantaged neighborhoods. Trained data collectors interviewed participants on a number of self-report measures, and objective neighborhood characteristics were obtained from city crime data and street segment audits.

RESULTS

Subjective characteristics, specifically perceived infrastructure and perceived safety, were associated with pain. Based on bootstrapped regression models, sleep efficiency and psychological distress were tested as mediators of the association between these neighborhood factors and pain. Results of mediation testing indicated that psychological distress served as a significant mediator. Though sleep efficiency was not a mediator, it had a significant independent association with pain.

CONCLUSIONS

Understanding the contribution of sleep problems and psychological distress to pain among at-risk individuals living in disadvantaged neighborhoods is important to identifying ways that individual- and neighborhood-level interventions may be leveraged to reduce pain-related disparities.

The Correlation Between PROMIS Pain Interference and VAS Pain in Ambulatory Orthopedic Patients

The purpose of this study was to investigate the correlation of Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference (PI) score with traditionally collected visual analog scale (VAS) scores and to determine the influence of patient demographics on PROMIS PI and VAS scores. Patient demographics were collected, and PROMIS PI, PROMIS Physical Function (PF), and VAS questionnaires were distributed to 215 patients in orthopedic ambulatory clinics. The primary outcome was correlation between PROMIS PI and VAS questionnaires. The statistical method of seemingly unrelated regressions was used to identify significant predictors and strengths of correlation between PROMIS PI and conventional forms. The PROMIS PI score was highly correlated to conventional pain and functional scores, with each standard deviation increase in PROMIS PI score predicting a 16-point increase for pain-related VAS scores (current pain, pain at rest, pain during activity, pain at night), an 18-point decrease in satisfaction of function score, and a 6-point decrease in general health score. Each standard deviation increase in PROMIS PF score for black patients predicted a reduction of 11 points for current pain, 10 points for pain at rest, 10 points for pain during activity, and 12 points for pain at night scores. The PROMIS PI score consistently predicts changes in VAS pain scores and can be considered a useful, standardized tool for measuring pain for clinical and research purposes. [Orthopedics. 2018; 41(6):e813-e819.].