Profiles of trauma exposure type and their associations to pain-related outcomes among adults with chronic pain: A two-year longitudinal study.

Individuals with chronic pain report disproportionally higher rates of trauma; yet, it is unclear whether different types of trauma (e.g., sexual, accidental trauma) are associated with worse pain outcomes. The present study sought to: 1) identify subgroups of people with chronic pain based on trauma type; and 2) determine whether subgroups differ in terms of pain characteristics over a two-year period. Individuals with chronic pain (N = 1,451) participated in an online study and completed self-report questionnaires at baseline, 3-, 12- and 24-month follow-up. Trauma was assessed via the Life Events Checklist for DSM-5. Pain intensity and interference were measured via the Brief Pain Inventory and pain distribution was evaluated using the Widespread Pain Index. Latent class analyses produced a three-class solution consisting of individuals with high and diverse trauma (16.3%), high sexual trauma (18.4%), and low/accidental trauma (57.1%) with the rest of the sample endorsing no trauma history (8.2%). After controlling for key demographic variables and baseline outcome levels, individuals in the high and diverse trauma group endorsed higher levels of pain severity and interference at the 3 and 12-month follow-ups compared to the group with no trauma (p<.01). Additionally, relative to the no trauma group, individuals in the high sexual trauma group reported higher levels of pain interference and more widespread pain at the 3-month follow-up (p<.05). Findings underscore the importance of screening for trauma and suggest that the type and variety of trauma experienced may be relevant to pain-related outcomes. PERSPECTIVE: This article highlights how an individual's unique trauma history may be related to their current pain experience. Knowledge of the type and frequency of past trauma may have relevant clinical implications for the treatment of chronic pain.

A preliminary examination of the effects of childhood abuse and resilience on pain and physical functioning in patients with knee osteoarthritis.

OBJECTIVES: We examined associations of a self-reported history of childhood abuse with pain and physical functioning in patients with knee osteoarthritis (KOA) awaiting total knee arthroplasty (TKA). We also explored the potential moderating effects of positive childhood experiences (PCEs), an index of resilience, on these associations. METHODS: Prior to TKA, participants with KOA awaiting surgery (N = 239) completed self-report measures of adverse childhood experiences (ACEs), PCEs, pain, and physical functioning. We evaluated associations of pain and physical functioning (Brief Pain Inventory [BPI] and Western Ontario and McMaster University of Osteoarthritis Index [WOMAC]) based on the experience of ACEs (childhood abuse), with PCEs (childhood happiness and supportive parental care) as potential moderators. RESULTS: Greater exposure to childhood abuse was positively correlated with BPI pain interference as well as WOMAC pain and functioning scores. Additionally, childhood happiness and supportive parental care moderated the positive associations of childhood abuse with pain and physical functioning; though, surprisingly, the adverse effects of childhood abuse on these outcomes were more pronounced among participants with high levels of childhood happiness and supportive parental care. CONCLUSION: Overall, results show an association between a self-reported history of childhood abuse and pain and functioning in patients with KOA awaiting TKA. However, PCEs did not protect against the negative consequences of childhood abuse in our cohort. Further research is needed to validate these associations and gain a more comprehensive understanding of the complex interplay between childhood abuse and PCEs and their potential influences on pain experiences in adults with chronic pain conditions, including KOA.

The association between changes in clinical pain severity and IL-6 reactivity among patients undergoing total knee Arthroplasty: The moderating role of change in insomnia.

Knee osteoarthritis (KOA) is linked to an enhanced release of interleukin-6 (IL-6). Increased levels of IL-6 are associated with greater pain and insomnia. While total knee arthroplasty (TKA) typically results in the reduction of pain, for a subgroup of patients, pain does not improve. Understanding patients' propensity to upregulate IL-6 may provide insight into variation in the clinical success of TKA for improving pain, and insomnia may play an important modulatory role. We investigated the association between pre- and post-surgical changes in clinical pain and IL-6 reactivity, and whether change in insomnia moderated this association. Patients (n = 39) with KOA came in-person before and 3-months after TKA. At both visits, patients completed validated measures of clinical pain and insomnia, as well as underwent quantitative sensory testing (QST). Blood samples were collected to analyze IL-expression both before and after QST procedures to assess changes in IL-6 in response to QST (IL-6 reactivity). Patients were categorized into two groups based on change in clinical pain from pre- to post-surgery: 1) pain decreased > 2 points (pain improved) and 2) pain did not decrease > 2 points (pain did not improve). Based on this definition, 49 % of patients had improved pain at 3-months. Among patients with improved pain, IL-6 reactivity significantly decreased from pre- to post-surgery, whereas there was no significant change in IL-6 reactivity among those whose pain did not improve. There was also a significant interaction between pain status and change in insomnia, such that among patients whose insomnia decreased over time, improved pain was significantly associated with a reduction in IL-6 reactivity. However, among patients whose insomnia increased over time, pain status and change in IL-6 reactivity were not significantly associated. Our findings suggest that the resolution of clinical pain after TKA may be associated with discernible alterations in pro-inflammatory responses that can be measured under controlled laboratory conditions, and this association may be moderated by perioperative changes in insomnia. Randomized controlled trials which carefully characterize the phenotypic features of patients are needed to understand how and for whom behavioral interventions may be beneficial in modulating inflammation, pain, and insomnia.

Elevated pain sensitivity is associated with reduced rapid eye movement (REM) sleep in females with comorbid temporomandibular disorder and insomnia.

OBJECTIVE: Patients with chronic pain disorders, including Temporomandibular Disorders (TMDs) endorse high levels of sleep disturbances, frequently reporting reduced sleep quality. Despite this, little is known about the effect that daytime pain has on the microstructure and macro-architecture of sleep. Therefore, we aimed to examine the extent to which daytime pain sensitivity, measured using quantitative sensory testing (QST), is associated with objective sleep parameters the following night, including sleep architecture and power spectral density, in women with TMD. METHODS: 144 females with myalgia and arthralgia by examination using the Diagnostic criteria for TMD completed a comprehensive QST battery consisting of General Pain Sensitivity, Central Sensitization Index, and Masseter Pressure Pain Threshold assessments. Polysomnography was collected the same night to measure sleep architecture and calculate relative power in delta, theta, alpha, sigma, and beta power bands. RESULTS: Central Sensitization (B = -3.069, P = .009), General Pain Sensitivity Indices (B = -3.069, P = .007), and Masseter Pain Pressure Threshold (B = 0.030, P = .008) were significantly associated with lower REM% both before and after controlling for covariates. Pain sensitivity measures were not significantly associated with relative power in any of the spectral bands nor with any other sleep architectural stages. CONCLUSIONS: Our findings demonstrate that higher generalized pain sensitivity, masseter pain pressure threshold, as well as central sensitization were associated with a lower percentage of REM in participants with myofascial pain and arthralgia of the masticatory system. These findings provide an important step toward understanding the mechanistic underpinnings of how chronic pain interacts with sleep physiology.

Sleep Disruption Moderates the Daily Dynamics of Affect and Pain in Sickle Cell Disease.

Persons with sickle cell disease (SCD) often experience pain that can interfere with quality of life and daily activities. Pain can modulated by affect and sleep continuity; however, few studies have explored how these factors complementarily influence pain in adults with SCD. The study aims were to investigate 1) whether pain levels were heightened on days characterized by low positive affect and high negative affect, and 2) whether the relationship between affect and pain was intensified following nights of disrupted sleep. Adults with SCD (N = 25) completed ecological momentary assessments and daily sleep diaries. Mixed models were used to analyze the main and interactive effects of daily affect (positive affect and negative affect) and sleep disruption (wake after sleep onset and frequency of awakenings) on both daily average pain and daily maximum pain. Results suggested that daily average pain and maximum pain tended to be higher on days of low positive affect and high negative affect. Furthermore, the frequency of nocturnal awakenings moderated the relationship between positive affect and pain. On days where there were higher frequencies of nocturnal awakenings, low positive affect was associated with both average and maximum pain; however, this association was not observed with lower frequencies of nocturnal awakenings. The association between negative affect and maximum pain was also stronger at higher levels of awakenings. Results highlight the relevance of adjunctive interventions that target affect among populations with SCD and further suggest that sleep continuity may further facilitate these interventions, highlighting the importance of multimodal treatments. PERSPECTIVE: This study examined the effects of affect and sleep on pain among adults with sickle cell disease (SCD). Higher pain occurred on days of low positive affect and high negative affect, particularly following nights of more frequent awakenings. These findings emphasize the importance of addressing affect and sleep in SCD treatment.

Children with sexual behavior problems: Ties to child maltreatment, family functioning, and help-seeking.

Although the literature on children's sexual behavior problems (SBPs) has indicated that maltreatment and family dysfunction are linked to SBPs, several facets of these factors have remained unexamined. Prior research has largely focused on SBPs more broadly, though interpersonal SBPs (ISBPs) are likely a distinct, more severe SBP subtype. The aim of the current study was to examine potentially relevant, unexplored factors, including the number of types of and total allegations of maltreatment as well as familial characteristics (i.e., parenting attitudes and behaviors, discipline methods, family functioning, and help-seeking) in relation to SBPs and ISBPs. The present study included 8-year-old children (N = 1,011, 51.1% female, 53.8% Black) and their caregivers from the Longitudinal Studies of Child Abuse and Neglect (LONGSCAN) study. In the model for SBPs, externalizing symptoms, the number of types of maltreatment allegations, maladaptive discipline methods, and help-seeking were associated with SBPs, whereas child's gender, race/ethnicity, internalizing symptoms, total maltreatment allegations, income, family functioning, and parenting attitudes were unrelated, r2 = .23. When ISBPs were examined, only child's gender and externalizing symptoms were tied to ISBPs, r2 = .09. However, child's race/ethnicity and internalizing symptoms, as well as maltreatment experiences, family factors, and help-seeking, were not associated with ISBPs. These findings highlight the importance of broader externalizing symptoms for both SBPs and ISBPs as well as the role of multiple types of maltreatment, parenting behavior, and help-seeking in the context of general SBPs.

Altered pain processing and sensitization in sickle cell disease: a scoping review of quantitative sensory testing findings.

OBJECTIVES: Over 50% of adults living with sickle cell disease (SCD) have chronic pain, but the underlying mechanisms of chronic pain in this population remain unclear. Quantitative sensory testing is an important measurement tool for understanding pain and sensory processing. This scoping review summarizes quantitative sensory testing methodologies used in sickle cell studies and the evidence for central sensitization in this population. METHODS: We conducted a systematic search of PubMed, Embase, and CINAHL to identify studies using quantitative sensory testing in individuals living with sickle cell disease. Search strategies were based on variations of the terms "sickle cell disease," and "quantitative sensory testing." Eligible studies were observational or experimental studies in human participants living with SCD that reported findings and detailed methodology for at least 1 quantitative sensory testing modality. RESULTS: Our search yielded a total of 274 records; 27 of which are included in this scoping review. Of the 27 studies, 17 were original studies (with combined total of 516 adult and 298 pediatric participants), and 10 were secondary or subgroup analyses of these prior studies. Significant variation existed in quantitative sensory testing methodologies across studies, including testing locations, type and intensity of stimuli, and interpretation of findings. Of the identified studies, 22% (2/9 studies) reported sensory abnormalities in mechanical sensitivity and thresholds, 22% (2/9 studies) reported abnormal pressure pain thresholds, 46% (6/13 studies) reported sensory abnormalities in thermal pain thresholds and tolerance (cold and warm), and 50% (2/4 studies) reported abnormalities in temporal summation. CONCLUSION: Future studies should use standardized quantitative sensory testing protocols with consistent and operationalized definitions of sensitization to provide clear insight about pain processing and central sensitization in sickle cell disease.

Change in Pain During Physical Activity Following Total Knee Arthroplasty: Associations With Improved Physical Function and Decreased Situational Pain Catastrophizing.

Background and Objectives: Knee osteoarthritis is one of the primary causes of chronic pain among older adults and because of the aging population, the number of total knee arthroplasties (TKAs) performed is exponentially increasing. While pain reduction is a goal of TKA, movement-evoked pain is rarely assessed pre- and post-TKA. We characterized the distributions of change in pain, function, and situational catastrophizing in patients from presurgery to 3 months postsurgery and explored associations among these pre-post changes. Research Design and Methods: This prospective study longitudinally assessed movement-evoked pain, function, and situational catastrophizing in patients with knee osteoarthritis (N = 92) using in-person performance-based tests (6-min walk test [6MWT], stair-climb test [SCT]) prior to and 3 months after TKA. Patients also completed the Western Ontario McMaster Universities Scales (WOMAC) pain and function subscales, and Pain Catastrophizing Scale, presurgery and 3- and 6-months postsurgery. Results: Movement-evoked pain and function on performance tests significantly improved from pre- to post-TKA. Improved SCT function was associated with reduced SCT pain and catastrophizing. Similarly, reduced pain during the SCT was associated with reduced catastrophizing during the SCT. However, 6MWT function was not associated with 6MWT pain or catastrophizing; yet reduced pain during the 6MWT was associated with reduced catastrophizing during the 6MWT. Reduced movement-evoked pain during both performance tests was consistently associated with improved WOMAC function and pain, whereas improved function on performance tests was inconsistently associated with WOMAC function and pain. Notably, greater movement-evoked pain on both performance tests at 3-month post-TKA was associated with worse WOMAC function and pain at 6 months, whereas better function on performance tests at 3 months was associated with better WOMAC function, but not related to WOMAC pain at 6 months. Discussion and Implications: Findings highlight the importance of situation-specific and in vivo assessments of pain and catastrophizing during physical activity.

Predictors of participation in online self-management programs: A longitudinal observational study.

PURPOSE/OBJECTIVE: Lack of patient participation and engagement remains a barrier to implementing effective online self-management and behavioral health interventions. Identifying patient characteristics associated with engagement rates may lead to interventions that improve engagement in traditional and online self-management programs. In this study, two online self-management and recovery programs were evaluated to identify factors that predict patient engagement. RESEARCH METHOD/DESIGN: Predictors were collected in a questionnaire at baseline before 435 participants started either of the two interventions. One or two online lessons were completed per week with seven or eight total lessons to complete in each program, and each lesson took about 20-30 min to finish. Full patient engagement was defined as completing all lessons and assessments in the program and partial engagement as attempting at least one lesson or assessment. RESULTS: Predictors of full patient engagement were self-rated confidence in completing the program or being over 60 years of age. Predictors of at least partial patient engagement were experienced ordering online or being over 50 years of age. CONCLUSIONS/IMPLICATIONS: Identifying profiles of individuals who predict poor engagement may improve implementation and the health outcomes of intervention programs. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Within subject, double blind, examination of opioid sensitivity in participant-reported, observed, physiologic, and analgesic outcomes.

Background: Inter-individual differences in opioid sensitivity may underlie different opioid risk profiles but have often been researched in persons who have current or past opioid use disorder or physical dependence. This study examined how opioid sensitivity manifests across various assessments of opioid effects in a primarily opioid-naïve population. Procedures: Data were harmonized from two within-subject, double-blind trials wherein healthy participants (N = 123) received placebo and 4 mg oral hydromorphone. Demographics, self-report ratings, observer ratings, physiological, and cold pressor measures were collected. Participants were categorized as being responsive or nonresponsive to the opioid dose tested and compared using mixed-models, Pearson product correlations, and paired t-tests. Findings: Participants were 49.6% female, mean 33.0 (SD=9.3) years old, and 44.7% Black/African American and 41.5% White, with 89.4% reporting no prior exposure to opioids. Within-subject sensitivity to opioids varied depending on the measure. One in five participants did not respond subjectively to the 4 mg hydromorphone dose based on their "Drug Effects" rating. Persons who were responsive showed more evidence of drug-dependent effects than did persons who were not responsive on ratings of Bad Effects (p= .03), feeling High (p= .01), Nausea (p= .03), pupil diameter (p< 0.01), and on the circular lights task (p< 0.001). Conclusions: This study provides initial evidence that the experience of opioids may be domain specific. Data suggest potentially clinically meaningful differences exist regarding opioid response patterns, evident following one dose among opioid inexperienced individuals.

Presurgical sleep and pain behaviors predict insomnia symptoms and pain after total knee arthroplasty: a 12-month longitudinal, observational study.

OBJECTIVE: Up to 40% of individuals who undergo total knee arthroplasty (TKA) experience some degree of pain following surgery. Presurgical insomnia has been identified as a predictor of postsurgical pain; however, modifiable presurgical behaviors related to insomnia have received minimal attention. The objective of the present study was to develop a 2-item sleep and pain behavior scale (SP2) to investigate a maladaptive sleep and pain behavior and is a secondary analysis of a larger, parent study. METHODS: Patients (N = 109) completed SP2 at baseline and 12 months and questionnaires assessing sleep and pain at baseline (pre-TKA), 6 weeks, 3, 6, and 12 months post-TKA. SP2 demonstrated adequate preliminary psychometric properties. RESULTS: As hypothesized, even after controlling for baseline insomnia, pain, anxiety and other covariates, baseline SP2 predicted insomnia symptom severity at 6 weeks (ß = 2.828), 3 (ß = 2.140), 6 (ß = 2.962), and 12 months (ß = 1.835) and pain at 6 weeks (ß = 6.722), 3 (ß = 5.536), and 6 months (ß = 7.677) post-TKA (P < .05). Insomnia symptoms at 6-weeks post-TKA mediated the effect of presurgical SP2 on pain at 3 (95% CI: 0.024-7.054), 6 (95%CI: 0.495-5.243), and 12 months (95% CI: 0.077-2.684). CONCLUSIONS: This provides preliminary evidence that patients who cope with pain by retiring to their bed and bedroom have higher rates of post-surgical insomnia and pain and supports efforts to target this maladaptive sleep and pain behavior to reduce postsurgical pain.

Perioperative insomnia trajectories and functional outcomes after total knee arthroplasty.

ABSTRACT: Longitudinal total knee arthroplasty (TKA) studies indicate that a substantial percentage of patients continue to experience clinically significant pain and functional impairment after surgery. Insomnia has been associated with poorer surgical outcomes; however, previous work has largely focused on long-term postsurgical insomnia. This study builds on previous work by examining sleep and pain outcomes about perioperative insomnia trajectories. Insomnia symptoms (using the Insomnia Severity Index) during the acute perioperative period (2 weeks pre-TKA to 6 weeks post-TKA) were used to classify participants into perioperative insomnia trajectories: (1) No Insomnia (ISI < 8), (2) New Insomnia (baseline < 8; postoperative ≥ 8 or ≥6-point increase), (3) Improved Insomnia (baseline ≥ 8, postoperative < 8 or ≥6-point decrease), and (4) Persistent Insomnia (ISI ≥ 8). Insomnia, pain, and physical functioning were assessed in participants with knee osteoarthritis (n = 173; M age = 65 ± 8.3, 57.8% female) at 5 time points: 2 weeks pre-TKA, post-TKA: 6 weeks, 3 months, 6 months, and 12 months. Significant main effects were seen for insomnia trajectory and time, and trajectory-by-time interactions for postoperative insomnia, pain severity, and physical functioning ( P' s < 0.05). The Persistent Insomnia trajectory had the worst postoperative pain at all follow-ups and marked insomnia and physical functioning impairment post-TKA ( P' s < 0.05). The New Insomnia trajectory had notable long-term insomnia (6 weeks to 6 months) and acute (6 weeks) postoperative pain and physical functioning ( P' s < 0.05). Findings indicated a significant relationship between perioperative insomnia trajectory and postoperative outcomes. Results of this study suggest that targeting presurgical insomnia and preventing the development of acute postoperative insomnia may improve long-term postoperative outcomes, with an emphasis on persistent perioperative insomnia due to poorer associated outcomes.

Medium- and Long-Term Effects of Insomnia Severity and Circadian Preference on Pain and Emotional Distress Among Individuals With Chronic Pain.

Studies have identified insomnia as having significant influence on chronic pain. A rising body of research has also underscored the association between eveningness and chronic pain. However, co-assessment of insomnia and eveningness in the context of chronic pain adjustment has been limited. The present study sought to investigate the effects of insomnia and eveningness on pain severity, pain interference, and emotional distress (ie, depressive and anxiety symptoms) over nearly 2 years among adults with chronic pain in the U.S. Adults with chronic pain (N = 884) were surveyed 3 times via Amazon's MTurk online crowdsourcing platform: baseline, 9-month follow-up, and 21-month follow-up. Path analysis was conducted to examine the effects of baseline insomnia severity (Insomnia Severity Index) and eveningness (Morningness and Eveningness Questionnaire), as well as their moderating effects on outcomes. Controlling for select sociodemographic variables and baseline outcome levels, greater insomnia severity at baseline was associated with worsening of all of the pain-related outcomes at 9-month follow-up, and pain interreference and emotional distress at 21-month follow-up. We did not find evidence that evening types are at a higher risk of experiencing worsening pain-related outcomes over time compared to morning and intermediate types. There were also no significant insomnia severity and eveningness moderation effects on any outcome. Our findings suggest that insomnia is a more robust predictor of changes in pain-related outcomes as compared to eveningness. Treatment of insomnia can be important in chronic pain management. Future studies should evaluate the role of circadian misalignment on pain using more accurate biobehavioral makers. PERSPECTIVE: This study examined the effects of insomnia and eveningness on pain and emotional distress in a large sample of individuals with chronic pain. Insomnia severity is a stronger predictor of changes in pain and emotional distress than eveningness, highlighting insomnia as an important clinical target for chronic pain management.

Race differences in pain and pain-related risk factors among former professional American-style football players.

ABSTRACT: The burden of pain is unequal across demographic groups, with broad and persisting race differences in pain-related outcomes in the United States. Members of racial and ethnic minorities frequently report more pervasive and severe pain compared with those in the majority, with at least some disparity attributable to differences in socioeconomic status. Whether race disparities in pain-related health outcomes exist among former professional football players is unknown. We examined the association of race with pain outcomes among 3995 former professional American-style football players who self-identified as either Black or White. Black players reported more intense pain and higher levels of pain interference relative to White players, even after controlling for age, football history, comorbidities, and psychosocial factors. Race moderated associations between several biopsychosocial factors and pain; higher body mass index was associated with more pain among White but not among Black players. Fatigue and psychosocial factors were more strongly related to pain among Black players relative to White players. Collectively, the substantial social and economic advantages of working as a professional athlete did not seem to erase race-related disparities in pain. We highlight an increased burden of pain among elite Black professional football players and identify race-specific patterns of association between pain and biopsychosocial pain risk factors. These findings illuminate potential future targets of interventions that may serve to reduce persistent disparities in the experience and impact of pain.

Within-subject, double-blind, randomized, placebo-controlled evaluation of combining the cannabinoid dronabinol and the opioid hydromorphone in adults with chronic pain.

The potential synergistic effects of combining cannabinoids and opioids for analgesia has received considerable attention. No studies to date have evaluated this combination in patients with chronic pain. The present study aimed to evaluate the combined analgesic and drug effects of oral opioid (hydromorphone) and delta-9-tetrahydrocannabinol (dronabinol), as well as their effects on physical and cognitive functioning, and human abuse potential (HAP) outcomes among individuals with knee osteoarthritis (KOA). This was a within-subject, double-blind, randomized, placebo-controlled study. Participants (N = 37; 65% women; mean age = 62) diagnosed with knee osteoarthritis of ≥3/10 average pain intensity were included. Participants received (1) placebo-placebo, (2) hydromorphone (4 mg)-placebo; (3) dronabinol (10 mg)-placebo, and (4) hydromorphone (4 mg)-dronabinol (10 mg). Clinical and experimentally-induced pain, physical and cognitive function, subjective drug effects, HAP, adverse events, and pharmacokinetics were evaluated. No significant analgesic effects were observed for clinical pain severity or physical functioning across all drug conditions. Little enhancement of hydromorphone analgesia by dronabinol was observed on evoked pain indices. While subjective drug effects and some HAP ratings were increased in the combined drug condition, these were not significantly increased over the dronabinol alone condition. No serious adverse events were reported; hydromorphone produced more mild adverse events than placebo, but hydromorphone + dronabinol produced more moderate adverse events than both placebo and hydromorphone alone. Only hydromorphone impaired cognitive performance. Consistent with laboratory studies on healthy adults, the present study shows minimal benefit of combining dronabinol (10 mg) and hydromorphone (4 mg) for analgesia and improving physical functioning in adults with KOA.

A randomized, placebo-controlled, double-blinded mechanistic clinical trial using endotoxin to evaluate the relationship between insomnia, inflammation, and affective disturbance on pain in older adults: A protocol for the sleep and Healthy Aging Research for pain (SHARE-P) study.

Chronic pain is prevalent in older adults. Treatment, especially with opioids, is often ineffective and poses considerable negative consequences in this population. To improve treatment, it is important to understand why older adults are at a heightened risk for developing chronic pain. Insomnia is a major modifiable risk factor for chronic pain that is ubiquitous among older adults. Insomnia can also lead to heightened systemic inflammation and affective disturbance, both of which may further exacerbate pain conditions in older adults. Endotoxin exposure can be used as an experimental model of systemic inflammation and affective disturbance. The current study aims to understand how insomnia status and endotoxin-induced changes in inflammation and affect (increased negative affect and decreased positive affect) may interact to impact pain facilitatory and inhibitory processes in older adults. Longitudinal data will also assess how pain processing, affective, and inflammatory responses to endotoxin may predict the development of pain and/or depressive symptoms. The current study is a randomized, double-blinded, placebo-controlled, mechanistic clinical trial in men and women, with and without insomnia, aged 50 years and older. Participants were randomized to either 0.8ng/kg endotoxin injection or saline placebo injection. Daily diaries were used to collect variables related to sleep, mood, and pain at two-week intervals during baseline and 3-, 6-, 9-, and 12-months post-injection. Primary outcomes during the experimental phase include conditioned pain modulation, temporal summation, and affective pain modulation ∼5.5 hours after injection. Primary outcomes for longitudinal assessments are self-reported pain intensity and depressive symptoms. The current study uses endotoxin as an experimental model for pain. In doing so, it aims to extend the current literature by: (1) including older adults, (2) investigating insomnia as a potential risk factor for chronic pain, (3) evaluating the role of endotoxin-induced affective disturbances on pain sensitivity, and (4) assessing sex differences in endotoxin-induced hyperalgesia. Clinicaltrialsgov: NCT03256760. Trial sponsor: NIH R01AG057750-01.

Individual Dimensions of Pain Catastrophizing Do Not Mediate the Effect of Sociodemographic and Psychological Factors on Chronic Orofacial Pain Severity, Interference, and Jaw Limitation: A Structural Equation Modeling Approach.

Pain catastrophization (PC), involving rumination, magnification, and helplessness, can be viewed as a coping strategy associated with chronic pain. PC is considered a driving force in mediating pain-related outcomes, but it is still unclear whether PC mediates the relationship between psychological and sociodemographic factors with chronic pain when considered in a single model. Using baseline data from a parent study, this study examined the effect of positive and negative psychological and sociodemographic factors on pain severity, interference, and jaw limitation mediated by the PC dimensions in a sample of 397 temporomandibular disorder (TMD) participants using structural equation modeling (SEM). SEM revealed that pain severity regressed on age, sex, education, and income; interference regressed on positive and negative psychological factors, education, and income; and jaw limitation regressed on age. The PC dimensions did not individually mediate these relationships. Although they jointly mediated the relationships between negative psychological factors and pain severity and between age and pain interference, the effect size was small, suggesting that PC is not a critical factor in mediating TMD pain outcomes. Reducing negative cognitions, not just PC, may be of greatest benefit to the most vulnerable TMD populations. PERSPECTIVE: This study examines sociodemographic and psychological factors that affect orofacial pain, finding that the pain catastrophizing dimensions do not mediate these relationships. Understanding which factors most strongly affect pain outcomes will help identify targets for intervention to produce the greatest benefit for the most vulnerable persons suffering from pain.

Comparing Pain and Pain Coping Mechanisms in Patients Undergoing Total Joint Arthroplasty as Part of a Mission Trip to Those in the United States.

BACKGROUND: Access to total joint arthroplasty can be difficult in low-resource settings. Service trips are conducted to provide arthroplasty care to populations in need around the world. This study aimed to compare the pain, function, surgical expectations, and coping mechanisms of patients from one such service trip to the United States. METHODS: In 2019, the Operation Walk program conducted a service trip in Guyana during which 50 patients had hip or knee arthroplasties. Patient demographics, patient-reported outcome measures, questionnaires assessing pain attitudes and coping, and pain visual analog scales were collected preoperatively and at 3 months postoperatively. These outcomes were compared with a matched cohort of elective total joint arthroplasty at a US tertiary care medical center. There were 37 patients matched between the 2 cohorts. RESULTS: The mission cohort had significantly lower preoperative self-reported function scores than the US cohort (38.3 versus 47.5, P = .003), as well as a significantly larger improvement at 3 months (42.4 versus 26.4, P = .014). The mission cohort had significantly higher initial pain (8.0 versus 7.0, P = .015), but there were no differences with regard to pain at 3 months (P = .420) or change in pain (P = .175). The mission cohort had significantly greater preoperative scores in pain attitude and coping responses. CONCLUSION: Patients in low-resource settings were more likely to have preoperative functional limitations and pain, and they coped with pain through prayer. Understanding the key differences between these 2 types of populations and how they approach pain and functional limitations may help improve care for each group. LEVEL OF EVIDENCE: II, prospective study.

Determining Profiles of Pain-Specific and General Emotion Regulation Skills and Their Relation to 12-Month Outcomes Among People With Chronic Pain.

Difficulties with pain-specific emotion regulation (ER; eg, pain catastrophizing, pain acceptance) are associated with poor pain outcomes. Less is known about how general ER relates to pain outcomes, or the extent to which pain-specific and general ER interact. In a sample (N = 1,453) of adults with chronic pain, the current study used latent profile analysis to identify subgroups of people with distinct pain-specific and general ER profiles, and determined how subgroup membership at baseline related to pain severity, pain interference, depression and anxiety symptoms at 12-month follow-up. Four groups were identified: 1) general ER difficulties only (29.6%); 2) pain-specific and general ER difficulties (26.3%); 3) skillful pain-specific and general ER (24.6%); 4) pain-specific ER difficulties only (19.4%). Controlling for auto-correlation and demographic covariates, those with pain-specific and general ER difficulties had the worst outcomes in all domains. Membership to other groups did not differentiate between pain severity or interference outcomes; those skillful in pain-specific and general ER had the lowest depression and anxiety symptoms at 12 months. General ER difficulties are common among adults with chronic pain and raise relative risk when paired with pain-specific ER difficulties. Findings offer potential directions for individualizing pain psychology treatment. PERSPECTIVE: This article shows that people with chronic pain have different sets of strengths and difficulties when it comes to regulating emotions related and/or unrelated to the experience of pain itself. Understanding an individual's unique constellation of emotion regulation skills and difficulties might help personalize the psychological treatment of pain.