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

Disparities in Clinical and Experimental Pain Between Non-Hispanic White and Asian American Individuals With Knee Osteoarthritis and the Role of Pain Catastrophizing: Pilot Study in Florida

BACKGROUND

Although a few studies have delineated the disparities in knee osteoarthritis (KOA) pain between non-Hispanic White and Asian American individuals, a significant research gap persists in elucidating the mechanisms underlying these differences.

OBJECTIVE

This pilot study aims to examine psychological factors, specifically pain catastrophizing and negative affect, as potential explanatory mechanisms for these dissimilarities.

METHODS

A cross-sectional design was used. Forty community-dwelling participants aged 50-70 years with self-reported KOA pain, including 20 non-Hispanic White and 20 Asian American individuals, were recruited in North Central Florida. Clinical KOA pain intensity was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the 4 subscales of the Short-Form McGill Pain Questionnaire-2. Quantitative sensory testing was conducted to measure experimental sensitivity to heat- and mechanically induced pain, including heat pain, pressure pain threshold, and punctate mechanical pain, as well as inhibitory pain processes through conditioned pain modulation. Pain catastrophizing was evaluated using the Coping Strategies Questionnaire-Revised Pain Catastrophizing subscale, while negative affect was assessed using the Positive and Negative Affect Schedule. Bayesian mediation analyses were used to examine both direct and indirect effects (mediation) between variables.

RESULTS

Asian American individuals exhibited higher pain catastrophizing scores than non-Hispanic White individuals. Pain catastrophizing, at high levels, contributed to WOMAC and Short-Form McGill Pain Questionnaire-2, which measured clinical pain. Race had no direct effects on these pain scores but exerted significant indirect effects via pain catastrophizing (WOMAC pain: 0.96, 95% CI 0.03-2.16; continuous pain: 0.84, 95% CI 0.18-1.70; intermittent pain: 0.78, 95% CI 0.03-1.71; neuropathic pain: 0.43, 95% CI 0.03-0.95; and affective pain: 1.05, 95% CI 0.24-1.99); thus, pain catastrophizing likely fully mediated the relationship between race and these pain measures. While Asian American individuals reported greater experimental pain sensitivity (heat pain, pressure pain threshold, and punctate mechanical pain) than non-Hispanic White individuals, these racial effects were not mediated by pain catastrophizing. Asian American individuals reported higher negative affect scores compared with non-Hispanic White individuals; however, negative affect did not mediate the relationship between race and any pain measures.

CONCLUSIONS

 The results demonstrate the contribution of pain catastrophizing to clinical pain in Asian American individuals with KOA and identify it as a potential mechanism underlying group differences in KOA pain between non-Hispanic White and Asian American individuals. However, caution is warranted due to the exploratory nature of this study and the treatment of Asian American individuals as a monolithic sample. Hence, future replication with larger and more diverse samples is necessary. Additionally, the lack of mediation effects of pain catastrophizing in the relationship between race and experimental pain suggests the need to explore other factors, such as biological, genetic, social, and environmental influences. Moreover, further research is essential to clarify the role of negative affect.

[Body, mind and culture : The complex dimensions of experiencing pain]

This article deals with the interrelationship between body, mind and culture with respect to being healthy and being ill. If one wants to treat not only sickness but also sick people, it is helpful to be aware not only of the somatic and psychological dimensions of a disease but also of the "cultural" dimension of a disease. Based on personal reflections and supplemented by a focused literature search this article provides insights into how cultural influences not only affect the experience of illness but also decide how an illness is dealt with individually and socially. Furthermore, it is shown that not only being sick but also the sick body can be understood in somatic, psychological and cultural dimensions and that a distinction must be made between the body as it physically is and as it is subjectively perceived. Finally, an insight into the complexity of the somatopsychic and psychosomatic interactions is provided in order to derivatively show how mental stress can lead to physical pain and physical pain can become a mental stressor.

Prevalence of temporomandibular disorders and their associated factors in Confucian heritage cultures: A systematic review and meta-analysis

BACKGROUND

Temporomandibular disorders (TMDs) may be an 'idiom' of psychological distress in Confucian heritage cultures (CHCs).

OBJECTIVES

This systematic review/meta-analysis estimated the prevalence of TMDs in CHCs and compared the differences in TMD occurrence between time periods and age groups. Additionally, the associated biopsychosocial risk factors were also examined.

METHODS

The study protocol was developed a priori following the PRISMA guidelines and Joanna Briggs Institute systematic review methodology (CRD42021245526). Electronic searches of seven databases were conducted from January 2002 to Dec 2021. Reference lists of identified studies were hand-searched for additional articles. Study selection, quality assessment, and data extraction were done. Meta-analysis was performed using the RevMan 5.4 software.

RESULTS

Forty-eight articles were included in the systematic review. Overall prevalences were: TMDs-15% (95% CI: 15-16%); TMD pain-8% (95% CI: 7-9%); TMJ sounds-24% (95% CI: 21-27%); and TMJ locking-7% (95% CI: 1-13%). While TMD prevalence appeared to have declined from 2002 to 2011 to 2012-2021, the occurrence of TMD pain, TMJ sounds, and locking increased marginally or remained constant. TMD prevalence in children/adolescents was 18% (95% CI: 14-22%) and 17% (95% CI: 16-18%) among adults. Significant associations between TMDs and bruxism/psychological distress/education levels were specified by 73%/90%/88% of the relevant studies.

CONCLUSIONS

TMDs are prevalent in CHCs and a slight increase in TMD pain (2%) and TMJ sounds (8%) were discerned over the past two decades. TMDs are related to a myriad of biopsychosocial variables, particularly psychological distress, and these factors must be addressed within the cultural context of patients.

Severity of Pain Catastrophizing and Its Associations With Cognitive Flexibility and Self-Efficacy in Patients With Rheumatoid Arthritis

BACKGROUND

Pain catastrophizing in patients with rheumatoid arthritis exacerbates negative pain-related outcomes, such as anxiety, depression, and pain intensity. Therefore, it is essential to investigate the severity of pain catastrophizing and the factors contributing to it among these patients. The present study aimed to assess the severity of pain catastrophizing and its association with cognitive flexibility and self-efficacy in a sample of Iranian patients with rheumatoid arthritis.

METHODS

A descriptive correlational study was conducted on 220 rheumatoid patients referred to a rheumatology clinic affiliated with Birjand University of Medical Sciences, Birjand, Iran. The instruments used to collect data included a demographic form, the Pain Catastrophizing Scale, the Cognitive Flexibility Inventory, and the Arthritis Self-Efficacy Scale. The data were analysed using SPSS version 24.

RESULTS

The mean age of the participants was 53.25 ± 12.41 years, and the mean duration of their disease was 6.63 ± 3.39 years. The majority of participants, specifically 61.8%, reported high levels of pain catastrophizing. An inverse and significant correlation was found between pain catastrophizing and cognitive flexibility (p < 0.001). Likewise, pain catastrophizing exhibited an inverse and significant correlation with self-efficacy and all its dimensions (p < 0.001). The results of the multiple linear regression analysis indicate that the final significant predictors of pain catastrophizing were cognitive flexibility (β = -0.34, p < 0.001) and self-efficacy (β = -0.53, p < 0.001). These predictors were found to significantly explain 51% of the variance in catastrophizing.

CONCLUSIONS

Through psychosocial interventions aimed at enhancing pain self-efficacy and cognitive flexibility, healthcare providers can hope to reduce pain catastrophizing and its adverse effects in patients with rheumatoid arthritis.

Pressure algometry in the general adult population: Age and sex differences

Experimental pain studies have revealed inter-individual variations in pain perception that are influenced by age, sex, and country of origin. This study aimed to explore the age and sex differences in pressure pain thresholds within the Iranian general population. To assess the pressure pain thresholds, a handheld pressure algometer was applied bilaterally to the middle fingers of both hands. The participants also completed the short form of the McGill Pain Questionnaire to provide a clinical pain rating. This cross-sectional study included 1610 adult subjects (54.96% female, mean age 40.13 ± 10.18 years). The findings indicated that females generally exhibited lower pain thresholds than males when assessing pain detection and tolerance parameters (P < .001). Females also demonstrated a significant lower pressure thresholds and clinical pain ratings compared with men (P < .001). Additionally, significant differences were observed between age groups in terms of pain detection and tolerance thresholds (P = .02 and P = .03, respectively). However, the interaction between sex and age was not significant. No significant differences in pain detection thresholds were observed between the right and left hand (P = .11). This study underscores the potential utility of algometry as a valuable tool for objectifying pain in the Iranian population.

Secondary analysis: heat and self-report pain sensitivity associate with biological sex and racialized sociocultural group but may not be mediated by anxiety or pain catastrophizing

Introduction

Previous studies have demonstrated associations between sex and racialized group on pain sensitivity and tolerance. We analyzed the association of sex and racialized group on heat pain sensitivity, sensibility to painful suprathreshold mechanical pain (STMP), and pain sensitivity questionnaire (PSQ). We hypothesized that anxiety and pain catastrophizing reported by racialized minority groups and women would mediate enhanced pain sensitivity. Our secondary aim was to evaluate validity of the PSQ in a diverse population.

Methods

Using quantitative sensory testing for painful heat, STMP (forces: 64, 128, 256, and 512 mN), and PSQ, we evaluated pain sensitivity in 134 healthy participants [34 (18 women) Asian, 25 (13 women) Black, and 75 (41 women) White]. We used general linear and linear mixed models to analyze outcomes. We assessed mediation of state and trait anxiety and pain catastrophizing on pain sensitivity.

Results

Racialized minority status was associated with greater heat pain sensitivity (F = 7.63; P = 0.00074) and PSQ scores (F = 15.45; P = 9.84 × 10-7) but not associated with STMP (F = 1.50; P = 0.23). Female sex was associated with greater heat pain sensitivity (F = 4.9; P = 0.029) and lower PSQ (F = 9.50; P = 0.0025) but not associated with STMP (F = 0.0018; P = 0.97). Neither anxiety nor pain catastrophizing mediated associations between sex or racialized group with heat pain threshold or PSQ. Differential experience of individual items (F = 19.87; P = 3.28 × 10-8) limited PSQ face validity in racialized minorities.

Conclusion

Consistent with previous research, sensitivity to painful heat was associated with racialized minority status and female sex. By contrast, there was no significant effect of racialized minority status or female sex on STMP. Some PSQ items are inapplicable to participants from racialized minority groups.

Recent Advances in Temporomandibular Joint Surgery

Temporomandibular disorders (TMDs) affect a high percentage of children and adults worldwide. Surgery may be indicated in severe or recalcitrant cases. Several recent advancements in TMD and temporomandibular joint (TMJ) surgery have elevated understanding and the ability to treat affected patients. We discuss recent advances in TMD epidemiology, juvenile idiopathic arthritis (JIA) of the TMJ, and surgical techniques and technologies. Technical advancements have been identified in TMJ arthroscopy, the treatment of TMJ subluxation and dislocation, and extended prosthetic total TMJ reconstruction (eTMJR). Overall, this review provides valuable insights into significant recent advancements in TMJ disorders and their surgical management.

Elucidating factors contributing to disparities in pain-related experiences among adults with or at risk for knee osteoarthritis

Background and purpose

We and others have reported ethnic/race group differences in clinical pain, physical function, and experimental pain sensitivity. However, recent research indicates that with consideration for socioenvironmental factors, ethnicity/race differences become less or non-significant. Understanding of factors contributing to pain inequities are needed. Guided by the NIA and NIMHD Health Disparities Research Frameworks, we evaluate the contributions of environmental and behavioral factors on previously reported ethnic/race group differences in: (1) clinical pain, (2) physical function, and (3) experimental pain in individuals with knee pain.

Methods

Baseline data from Understanding of Pain and Limitations in Osteoarthritis Disease (UPLOAD) and UPLOAD-2 studies were analyzed. Participants were adults 45 to 85 years old who self-reported as non-Hispanic white (NHW) or black (NHB) with knee pain. A health assessment and quantitative sensory testing were completed. Sociodemographics, environmental, health, clinical and experimental pain, and physical functioning measures were included in nested regressions.

Results

Pooled data from 468 individuals, 57 ± 8 years of age, 63% women, and 53% NHB adults. As NHB adults were younger and reported greater socioenvironmental risk than the NHW adults, the term sociodemographic groups is used. With inclusion of recognized environmental and behavioral variables, sociodemographic groups remained a significant predictor accounting for <5% of the variance in clinical pain and physical function and <10% of variance in experimental pain.

Conclusion

The incorporation of environmental and behavioral factors reduced relationships between sociodemographic groups and pain-related outcomes. Pain sites, BMI, and income were significant predictors across multiple models. The current study adds to a body of research on the complex array of factors contributing to disparities in pain-related outcomes.

Biological sex influences psychological aspects of the biopsychosocial model related to chronic pain intensity and interference among South Korean patients with chronic secondary musculoskeletal pain in rheumatic diseases

Introduction

Pain is a prominent contributor to negative personal and social outcomes, including increased disability and mortality, in many rheumatic diseases. In the Biopsychosocial model of chronic pain, psychological and social factors share roles with the biology of the injury in determining each patient's pain and suffering. The current study explored factors associated with clinical pain intensity and interference among patients with chronic secondary musculoskeletal pain in rheumatic diseases.

Methods

In total, 220 patients experiencing chronic secondary musculoskeletal pain participated. Biological factors (age, biological sex, pain condition, pain duration, pain sensitivity, and comorbidity), socio-economic factors, psychological factors (pain catastrophizing and depressive symptoms), and pain intensity and interference were measured. Descriptive, multivariable linear regression and partial correlation analyses were conducted. Subgroup analysis by sex was conducted to examine differences in how different factors affect the pain experience.

Results

The mean age of the participants was 52.3 years (SD = 12.07) and ranged from 22 to 78. Average pain intensity was 3.01 (0-10 scale) and average total pain interference score was 21.07 (0-70 scale). Partial correlation found positive correlations between pain intensity and interference with depression (intensity: R = 0.224; p = 0.0011; interference: R = 0.351; p < 0.001) and pain catastrophizing (intensity: R = 0.520; p < 0.001; interference: R = 0.464; p < 0.001). In males, pain condition (β = -0.249, p = 0.032) and pain catastrophizing (R = 0.480, p < 0.001) were associated with pain intensity. In males, the simple correlation between pain intensity and depression (R = 0.519; p < 0.001) was driven by pain catastrophizing. In females, pain catastrophizing (R = 0.536, p < 0.001) and depressive symptoms (R = 0.228, p = 0.0077) were independently associated with pain intensity. Age (β = -0.251, p = 0.042) and pain catastrophizing (R = 0.609, p < 0.001) were associated with pain interference in males, while depressive symptoms (R = 0.439, p < 0.001) and pain catastrophizing (R = 0.403, p < 0.001) were associated with pain interference in females. Again, in males, the simple correlation between pain interference and depression (R = 0.455; p < 0.001) was driven by pain catastrophizing.

Discussion

In this study, females were more directly affected by depressive symptoms than males, regarding pain intensity and interference. Pain catastrophizing was a significant factor influencing chronic pain for both males and females. Based on these findings, a sex-specific approach to the Biopsychosocial model should be considered in understanding and managing pain among Asians with chronic secondary musculoskeletal pain.

Psychosocial and Sensory Factors Contribute to Self-Reported Pain and Quality of Life in Young Adults with Irritable Bowel Syndrome

AIMS

Psychosocial and sensory factors, including anxiety, depression, and pressure pain threshold have been used to cluster chronic symptoms in irritable bowel syndrome (IBS). This study examined the contribution of psychosocial sensory factors on pain interference and quality of life (QOL) in this population.

DESIGN

We performed a cross-sectional analysis of baseline data from a randomized controlled trial.

SETTINGS

Two gastrointestinal clinics, general communities, and two large campuses of a public university in the Northeastern United States.

PARTICIPANTS/SUBJECTS

Eighty young adults with IBS aged 21 ± 2.57 years (76.25% female).

METHODS

Demographic and psychosocial factors including anxiety, depression, fatigue, cognition or general concerns, sleep disturbance, self-efficacy, coping, and food intake were measured as independent variables. Quantitative sensory testing was conducted to measure mechanical, thermal, and pressure pain thresholds. Self-reported pain measured by the brief pain inventory (BPI) and IBS-QOL were assessed as the outcome variables. Regression analysis and mediation analysis were conducted to determine the associated factors of IBS pain and QOL.

RESULTS

Age, sex, and psychosocial factors including coping, self-efficacy, alcohol intake, mechanical pain sensitivity, and cold pain threshold were significantly associated with pain interference (all p < 0.05). Coping, and self-efficacy were significantly associated with IBS-QOL (all p < 0.05). In the mediation analysis, coping catastrophizing and self-efficacy were indirectly associated with IBS-QOL mediated by fatigue.

CONCLUSIONS

Psychosocial factors including coping and self-efficacy, and quantitative sensory testing factors significantly correlate with self-reported pain and QOL among young adults with IBS. This preliminary research calls for further interventional studies that target personalized psychosocial and quantitative sensory factors to improve pain management and quality of life in IBS patients.

Sodium-calcium exchanger-3 regulates pain "wind-up": From human psychophysics to spinal mechanisms

Repeated application of noxious stimuli leads to a progressively increased pain perception; this temporal summation is enhanced in and predictive of clinical pain disorders. Its electrophysiological correlate is "wind-up," in which dorsal horn spinal neurons increase their response to repeated nociceptor stimulation. To understand the genetic basis of temporal summation, we undertook a GWAS of wind-up in healthy human volunteers and found significant association with SLC8A3 encoding sodium-calcium exchanger type 3 (NCX3). NCX3 was expressed in mouse dorsal horn neurons, and mice lacking NCX3 showed normal, acute pain but hypersensitivity to the second phase of the formalin test and chronic constriction injury. Dorsal horn neurons lacking NCX3 showed increased intracellular calcium following repetitive stimulation, slowed calcium clearance, and increased wind-up. Moreover, virally mediated enhanced spinal expression of NCX3 reduced central sensitization. Our study highlights Ca2+ efflux as a pathway underlying temporal summation and persistent pain, which may be amenable to therapeutic targeting.

Demoralization level fluctuated at various time frame of radiotherapy for patients with different cancers: a longitudinal observational study

Background

Demoralization is a psychological response that is frequently observed in patients with cancer or advanced diseases. It is affected by national characteristics, culture, disease characteristics and general conditions of the patient such as individual cultural features, nature of stress, personal expression preferences and social behavior. Compared with the results of previous studies on demoralization syndrome, patients with cancer in Taiwan exhibit a higher prevalence of demoralization. We aimed to investigate the prevalence of high demoralization and the changes in the level of demoralization in cancer patients during radiotherapy to explore the associated factors and the contributing factors to the high level of demoralization.

Methods

We used the Demoralization Scale-Mandarin Version to evaluate the demoralization level at six-time points in patients admitted for radiotherapy in a 3-month observational period. 101 patients allocated to three groups by cancer region completed the study. We applied the generalized estimating equation (GEE) to analyze the changes in the demoralization level among the three groups. The variables associated with the changes in the demoralization level were also investigated.

Results

In the analysis using univariate GEE, only patients in the chest and breast group exhibited significant changes at two different time points. The results obtained using multivariate GEE revealed that sociodemographic variables, stage of disease and use of surgery or chemotherapy had no impact on the changes in demoralization across three months.

Conclusion

The demoralization level certainly fluctuated in an extremely high range. The higher prevalence of demoralized patients may indicate that if medical staff neglect the importance of demoralization, demoralized patients with cancer may not receive appropriate care.

Somatosensory Profiles Differentiate Pain and Psychophysiological Symptoms Among Young Adults With Irritable Bowel Syndrome: A Cluster Analysis

OBJECTIVE

The aim of this study was to investigate if somatosensory profiles can differentiate pain and psychophysiological symptoms among young adults with irritable bowel syndrome (IBS).

METHODS

We performed a cluster analysis of data collected from a randomized clinical trial of 80 IBS patients and 21 age-matched healthy controls (HCs) to stratify pain and symptoms among young adults with IBS by their peripheral sensory profiles. Data of quantitative sensory testing and IBS-related pain and symptoms were collected at baseline and 6-week and 12-week follow-ups.

RESULTS

Using the K-means method, IBS patients were classified into 2 clusters, the "IBS normal threshold" (IBS-NT) and the "IBS increased threshold" (IBS-IT). The IBS-NT cluster had a similar pain threshold as the HCs, and the IBS-IT cluster had an increased threshold of somatic pain perception (lower cold pain threshold, higher heat pain threshold, and higher pressure pain threshold, all P<0.001) than HCs. Compared with the IBS-NT cluster, the IBS-IT cluster reported higher levels of IBS-related pain intensity, anxiety, fatigue, and sleep disturbance over the 3 visits (all P<0.05).

DISCUSSION

Young adults with IBS fell into 2 clusters, one with a similar sensory threshold as the HCs and another with an increased pain threshold, who reported higher pain intensity and more severe symptoms. Somatic sensory profiles should be integrated into further personalized self-management intervention among patients with IBS.

Regulatory Emotional Self-Efficacy Buffers the Effect of Heart Rate Variability on Functional Capacity in Older Adults With Chronic Low Back Pain

Introduction

Chronic low back pain is one of the leading causes of disability globally among older adults. Prevailing research suggests that autonomic dysregulation places individuals at increased risk for chronic pain. This study examines the moderating role of emotional self-efficacy (ESE) on the relationship between heart rate variability (HRV) and pain related-outcomes, including movement-evoked pain (MEP) and physical functioning.

Methods

In a secondary analysis of the Adaptability and Resilience in Aging Adults (ARIAA) study, a total of 58 adults (aged 60 and older) with chronic low back pain (cLBP) completed the PROMIS self-efficacy for managing emotions questionnaire and the 6-minute walk test (6 MWT) to assess functional capacity and MEP. Heart rate variability, indexed by the frequency domain, was assessed for 5 min during rest.

Results

For pain-related outcomes, having a lower body mass index (p = 0.03) was associated with better functional capacity on the 6MWT, while higher education level (p = 0.01) and less pain duration (p = 0.00) were correlated with lower MEP. After controlling for sex, age, and body mass index, an increase in low-frequency HRV (LF-HRV) was associated with poorer physical functioning among individuals low in ESE (b = −0.12 p = 0.03). No significant moderation effects were observed for MEP.

Conclusion

Our results bring attention to the degree to which ESE influences the relationship between LF-HRV and physical functioning. Interventions that enhance adaptive psychological processes such as ESE may dampen ANS dysregulation and mitigate risk for adverse pain outcomes among older adults with cLBP.

Pain catastrophizing: A patient-centered approach to assessment

ABSTRACT

Pain is a subjective experience and its perception and expression vary widely. Pain catastrophizing, which refers to patients' thoughts or feelings about their pain, may impact their communication of pain and nurses' subsequent response. This article discusses how nurses can more readily recognize, assess, and manage pain catastrophizing.

An overview of pain assessment and management

Pain is a distressing, subjective and complex phenomenon that all nurses will encounter in their clinical practice. Effective pain management requires nurses to undertake a structured assessment to identify the probable causes of pain and guide management. Interventions used to reduce pain can be varied and multimodal. This article provides an overview of pain including its definition, classifications, assessment and management. It emphasises the importance of a person-centred approach to care which reflects Margo McCaffery's seminal quote that pain is 'whatever the experiencing person says it is'.

Simple Quantitative Sensory Testing Reveals Paradoxical Co-existence of Hypoesthesia and Hyperalgesia in Diabetes

Background: Diabetic neuropathy is characterized by the paradoxical co-existence of hypo- and hyperalgesia to sensory stimuli. The literature shows consistently sensory differences between healthy and participants with diabetes. We hypothesized that due to differences in pathophysiology, advanced quantitative sensory testing (QST) might reveal sensory discrepancies between type 1 (T1D) and type 2 diabetes (T2D). Furthermore, we investigated whether vibration detection thresholds (VDT) were associated with sensory response.

Method: Fifty-six adults with T1D [43 years (28–58)], 99 adults with T2D [65 years (57–71)], and 122 healthy individuals [51 years (34–64)] were included. VDT, pressure pain detection thresholds (pPDT) and tolerance (pPTT), tonic cold pain (hand-immersion in iced water), and central pain mechanisms (temporal summation and conditioned pain modulation) were tested and compared between T1D and T2D. VDT was categorized into normal (< 18 V), intermediary (18–25 V), or high (> 25 V).

Results: In comparison to healthy, analysis adjusted for age, BMI, and gender revealed hypoalgesia to tibial (pPDT): p = 0.01, hyperalgesia to tonic cold pain: p < 0.01, and diminished temporal summation (arm: p < 0.01; abdomen: p < 0.01). In comparison to participants with T2D, participants with T1D were hypoalgesic to tibial pPDT: p < 0.01 and pPTT: p < 0.01, and lower VDT: p = 0.02. VDT was not associated with QST responses.

Conclusion: Participants with T1D were more hypoalgesic to bone pPDT and pPTT independent of lower VDT, indicating neuronal health toward normalization. Improved understanding of differentiated sensory profiles in T1D and T2D may identify improved clinical endpoints in future trials.

Heart Rate Variability and Pain: A Systematic Review

Background and Objective: Heart rate variability (HRV) as an index of the autonomic nervous system appears to be related to reactivity to experimental pain stimuli. HRV could better explain the contributions of sympathetic and parasympathetic activity response to nociceptive stimulation. The aim of this study was to systematically review and synthesize the current evidence on HRV in relation to the experience of pain in experimental tasks. Databases and Data Treatment: Studies indexed in the PubMed, PsycINFO, MEDLINE, WebOfScience, and Scopus databases were reviewed for eligibility. Studies on the autonomic response (i.e., HRV) to experimentally induced pain in healthy adults were included. Different methods of pain induction were considered (e.g., thermal, pressure, and electrical). Data were synthesized considering the association between HRV and both pain induction and subjective measures of pain. Results: Seventy-one studies were included. The results underline significant change in both the sympathetic and parasympathetic autonomic nervous systems during the painful stimulation independent of the pain induction method. The autonomic reaction to pain could be affected by several factors, such as sex, age, body mass index, breathing patterns, the intensity of the stimulation, and the affective state. Moreover, an association between the autonomic nervous system and the subjective experience of pain was found. Higher parasympathetic activity was associated with better self-regulation capacities and, accordingly, a higher pain inhibition capacity. Conclusions: HRV appears to be a helpful marker to evaluate nociceptive response in experimentally induced pain. Future studies are also needed in clinical samples to understand better the interindividual changes of autonomic response due to pain stimuli.

Unsupervised Machine Learning Identified Distinct Population Clusters Based on Symptoms of Oral Pain, Psychological Distress, and Sleep Problems

Objectives:

The aims of this study were to explore the use of unsupervised machine learning in clustering the population based on reports of oral pain, psychological distress, and sleep problems and to compare demographic and socio-economic characteristics as well as levels of functional domains (work, social, and leisure) between clusters.

Materials and Methods:

In this cross-sectional study, a total of 1613 participants from the National Health and Nutrition Examination Survey in 2017–2018 were analyzed. Five variables, including oral pain, depression, anxiety, sleep apnea, and excessive daytime sleepiness, were selected for cluster analysis using the k-medoids clustering algorithm. The distribution of categorical variables between clusters was assessed using χ² test. One-way analysis of variance and Kruskal–Wallis H test were used to compare numerical variables as appropriate.

Results:

Five distinct clusters were identified: healthy, norm, anxiety, apnea-comorbid, and pain-comorbid. The apnea-comorbid cluster had mean age of 59 years and higher proportion of men. The pain-comorbid cluster had mean age of 56 years and higher proportion of women. Whites constituted a majority of both comorbid clusters. The pain-comorbid cluster demonstrated the least percentage of individuals with college degree, the lowest income, and significant impairment in all functional domains.

Conclusion:

Through the use of unsupervised machine learning, the clusters with comorbidity of oral pain, psychological distress, and sleep problems have emerged. Major characteristics of the comorbid clusters included mean age below 60 years, White, and low levels of education and income. Functional domains were significantly impaired. The comorbid clusters thus call for public health intervention.

Pharmacogenomic Testing and Patient Perception Inform Pain Pharmacotherapy

(1) Background: Chronic pain is one of the most common reasons for individuals to seek medications. Historically, opioids have been the mainstay of chronic pain management. However, in some patient populations, opioids fail to demonstrate therapeutic efficacy, whereas in other populations, opioids may cause toxic effects, even at lower doses. Response to pain medication is affected by many factors, including an individual's genetic variations. Pharmacogenomic testing has been designed to help achieve optimal treatment outcomes. This study aimed at assessing the impact of CYP2D6 pharmacogenomic testing on physicians' choice in prescribing chronic pain medications and patient pain control. (2) Methods: This retrospective study reviewed 107 patient charts from a single site pain management center. All 107 patients received pharmacogenomic testing. The outcomes of interest were confirmation that the optimal pain medication is being administered or a change in the chronic pain medication is warranted as a result of the pharmacogenomic testing. The main independent variable was the pharmacogenomic test result. Other independent variables included patient gender, race, and comorbidities. The retrospective study was reviewed and approved by the Touro College and University System IRB, HSIRB1653E. (3) Results: Patients self-reported pain intensity on a scale of 1-10 before and after pharmacogenomic testing. Then, 100% of patients in the retrospective study were tested for their pain pharmacogenomic profile. Of the 107 patients participating in the study, more than 50% had their medications altered as a result of the pharmacogenomic testing. The percentage of patients with intense pain were decreased post-pharmacogenomic testing (5.6%) as compared to pre-pharmacogenomic testing (10.5%). Patients with intense, moderate, and mild pain categories were more likely to receive changes in pain medications. In contrast, patients with severe pain were less likely to receive a change in pain medication. Hispanic ethnicity was associated with a statistically significantly decrease in a pain scale category. Illegal drug abuse was associated with a decrease in pain scale category. Change in medication dose was associated with a decrease in pain scale category. (4) Conclusion: In this retrospective study, implementation of pharmacogenomic testing demonstrated significant benefits to patients with intense pain undergoing treatment.

Demoralization syndrome among cardiac transplant recipients

AIMS AND OBJECTIVES

To investigate the characteristics and prevalence of demoralisation syndrome among heart transplantation patients in Taiwan.

BACKGROUND

Patients with end-stage heart failure who have undergone cardiac transplantation are at risk of demoralisation syndrome. Demoralisation syndrome has been studied in cancer populations, but our understanding of the syndrome among heart transplant recipients is limited.

DESIGN AND METHODS

The study adopted a cross-sectional design and analysed the baseline data from a longitudinal study with cardiac transplant patients at a heart centre in northern Taiwan. A structured questionnaire, namely the Demoralization Scale-Mandarin Version (DS-MV), was used to assess demoralisation syndrome. Hierarchical regression was applied to determine the predictors of demoralisation. Reporting was consistent with the STROBE checklist.

RESULTS

There were a total of 84 participants with an average age of 51.9 years and a time since heart transplantation of around 4.1 years. Among them, the prevalence of demoralisation syndrome was 35.8%, and 57.1% coped well with stress. In addition, on the DS-MV, participants tended to choose sentences with positive rather than negative wording. Our data showed that cardiac transplant recipients with stress have higher possibility suffering from demoralisation syndrome; poor renal function and those who cannot relive from stress are predictors for loss of meaning.

CONCLUSIONS

Chinese individuals tend to hide their weaknesses; nevertheless, demoralisation syndrome among cardiac transplant recipients, as related to stress status and kidney function, is still remarkable.

RELEVANCE TO CLINICAL PRACTICE

Since demoralisation is preventable, further research on this phenomenon in the cardiac transplant population is warranted and needs to be developed.

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 Mediating Role of Pain Catastrophizing on the Association Between Depression and Pain Severity and Interference Among Elderly Asian Immigrants with Chronic Pain

Purpose

The association between depression and chronic pain is well established. However, few studies have examined the pathways from depression to chronic pain. The present cross-cultural study aimed to test the mediating effects of pain catastrophizing on associations between depression and chronic pain (eg, pain severity, pain intensity) among Korean American elderly.

Patients and Methods

A total of 132 elderly Korean Americans with chronic pain were recruited from elderly daycare centers and Korean ethnic churches in the community. For mediation analyses, structural equation modeling with full information maximum likelihood estimation method was used. The bias-corrected bootstrap confidence interval (CI) method for inferential tests of the indirect effects was also conducted in mediation analysis.

Results

The results indicated that the proportion of comorbid depression and chronic pain was 45.7%. Elderly Korean Americans with depression scored higher in pain severity, pain interference, and pain catastrophizing than those without depression. Pain catastrophizing was found to have a significant mediating effect on the relationship between depression and pain severity (indirect effect = 0.147, Bootstrap 95% CI = [0.079, 0.226]), controlling for demographic covariates, comorbidities and pain area. Pain catastrophizing also mediated the relationship between depression and pain interference (indirect effect =0.164, Bootstrap 95% CI = [0.097, 0.244]), controlling for the covariates.

Conclusion

These findings add to the literature by providing evidence that pain catastrophizing plays a role in high levels of pain severity and pain interference comorbid chronic pain and depression in Asian elderly immigrants. Appropriate culturally tailored programs to redirect pain catastrophizing cognitive process should be developed and provided for elderly Asian Americans to reduce chronic pain disparity.

Resilience, pain, and the brain: Relationships differ by sociodemographics

Chronic musculoskeletal (MSK) pain is disabling to individuals and burdensome to society. A relationship between telomere length and resilience was reported in individuals with consideration for chronic pain intensity. While chronic pain associates with brain changes, little is known regarding the neurobiological interface of resilience. In a group of individuals with chronic MSK pain, we examined the relationships between a previously investigated resilience index, clinical pain and functioning measures, and pain-related brain structures, with consideration for sex and ethnicity/race. A cross-sectional analysis of 166 non-Hispanic Black and non-Hispanic White adults, 45-85 years of age with pain ≥ 1 body site (s) over the past 3 months was completed. Measures of clinical pain and functioning, biobehavioral and psychosocial resilience, and structural MRI were completed. Our findings indicate higher levels of resilience associate with lower levels of clinical pain and functional limitations. Significant associations between resilience, ethnicity/race, and/or sex, and pain-related brain gray matter structure were demonstrated in the right amygdaloid complex, bilateral thalamus, and postcentral gyrus. Our findings provide compelling evidence that in order to decipher the neurobiological code of chronic pain and related protective factors, it will be important to improve how chronic pain is phenotyped; to include an equal representation of females in studies including analyses stratifying by sex, and to consider other sociodemographic factors.

Parent responses to pediatric pain: The differential effects of ethnicity on opioid consumption

OBJECTIVE

Within the context of the United States opioid epidemic, some parents often fear the use of opioids to help manage their children's postoperative pain. As a possible consequence, parents often do not dispense optimal analgesic medications to their children after surgery, putting their children at risk of suffering from postsurgical pain. The objective of this research was to assess ethnicity as a predictor of both pain and opioid consumption, and to examine how Hispanic/Latinx and Non-Hispanic White parents alter their child's opioid consumption in response to significant postsurgical pain.

METHODS

Participants were 254 children undergoing outpatient tonsillectomy and/or adenoidectomy surgery and their parents. Longitudinal multilevel modeling examined changes in both parent-reported pain and hydrocodone/APAP consumption (mg/kg) on days 1 to 7 after surgery.

RESULTS

Parent reports of postoperative pain were higher in Hispanic/Latinx patients compared to their Non-Hispanic White counterparts (β = -0.15; 95% CI: -0.28, -0.01). There was also a significant interaction of ethnicity and pain on opioid consumption (β = 0.07; 95% CI: 0.01, 0.13). The relationship between parent perceived pain and opioid use was stronger for Non-Hispanic White children, suggesting that this group was more likely to consume opioids to help manage clinically significant postsurgical pain.

CONCLUSIONS

Hispanic/Latinx children might be at risk for undertreatment of surgical pain. Findings highlight the importance of assessing parent background and cultural beliefs as predictors of at home pain management and the potential effectiveness of tailored interventions that educate parents about monitoring and treating child postoperative pain.

Placebo hypoalgesia: racial differences

No large-cohort studies that examine potential racial effects on placebo hypoalgesic effects exist. To fill this void, we studied placebo effects in healthy and chronic pain participants self-identified as either African American/black (AA/black) or white. We enrolled 372 study participants, 186 with a diagnosis of temporomandibular disorder (TMD) and 186 race-, sex-, and age-matched healthy participants to participate in a placebo experiment. Using a well-established paradigm of classical conditioning with verbal suggestions, each individual pain sensitivity was measured to calibrate the temperatures for high- and low-pain stimuli in the conditioning protocol. These 2 temperatures were then paired with a red and green screen, respectively, and participants were told that the analgesic intervention would activate during the green screens to reduce pain. Participants then rated the painfulness of each stimulus on a visual analog scale ranging from 0 to 100. Racial influences were tested on conditioning strength, reinforced expectations, and placebo hypoalgesia. We found that white participants reported greater conditioning effects, reinforced relief expectations, and placebo effects when compared with their AA/black counterparts. Racial effects on placebo were observed in TMD, although negligible, short-lasting, and mediated by conditioning strength. Secondary analyses on the effect of experimenter-participant race and sex concordance indicated that same experimenter-participant race induced greater placebo hypoalgesia in TMDs while different sex induced greater placebo hypoalgesia in healthy participants. This is the first and largest study to analyze racial effects on placebo hypoalgesia and has implications for both clinical research and treatment outcomes.

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.

Chronic pain, cardiovascular health and related medication use in ageing African Americans with osteoarthritis

AIM AND OBJECTIVES

To describe the (a) prevalence and perceptions of cardiovascular disease and related health conditions in African Americans with osteoarthritis pain, (b) their knowledge of cardiovascular safety of commonly prescribed analgesics for osteoarthritis and (c) frequency of high-risk analgesic use.

BACKGROUND

African Americans have more disabling osteoarthritis pain and an excessive burden of cardiovascular disease than any other US racial group. However, minimal research has investigated the relationship between chronic pain and cardiovascular disease and subsequent medication knowledge and use in African Americans. Consolidated Criteria for Reporting Qualitative and Srengthening the Reporting of Observational studies in Epidemiology checklists were followed.

DESIGN

A descriptive, secondary mixed-methods analysis.

METHODS

A convenience sample of 110 African American adults (50-94 years and older) completed surveys and individual qualitative interviews. Data were analysed using descriptive statistics, chi-square or Fisher's exact test, t test, Mann-Whitney U and a qualitative content analysis.

RESULTS

Hypertension was the most common cardiovascular condition reported, and African Americans with hypertension reported greater pain than those without. The survey questions revealed that most participants did not possess accurate knowledge about the appropriateness of analgesics in heart failure and other cardiovascular-related diseases; however, during the interviews, some did acknowledge a general understanding of the negative effects of some medications. Still, many older adults were taking nonsteroidal anti-inflammatory drugs despite having hypertension.

CONCLUSIONS

There was evidence of multimorbidity in our sample; based on our data, chronic osteoarthritis pain and hypertension are two highly comorbid conditions, suggesting a possible syndemic. More disparate is the lack of knowledge that African Americans possess as it relates to safe use of analgesic medications when cardiovascular disease is present.

RELEVANCE TO CLINICAL PRACTICE

Chronic pain and cardiovascular-related diseases are common and often co-occur and should be evaluated in all older adults, particularly African Americans. Both issues are important to manage, including the safe and appropriate use of medications, to prevent adverse effects.

Biomarkers in Temporomandibular Disorder and Trigeminal Neuralgia: A Conceptual Framework for Understanding Chronic Pain

In this review, we will explore the use of biomarkers in chronic pain, using the examples of two prototypical facial pain conditions: trigeminal neuralgia and temporomandibular disorder. We will discuss the main categories of biomarkers and identify various genetic/genomic, molecular, neuroradiological, and psychophysical biomarkers in both facial pain conditions, using them to compare and contrast features of neuropathic, nonneuropathic, and mixed pain. By using two distinct model facial pain conditions to explore pain biomarkers, we aim to familiarize readers with different types of biomarkers currently being studied in chronic pain and explore how these biomarkers may be used to develop new precision medicine approaches to pain diagnosis, prognosis, and management.