Pain and the Montreal Cognitive Assessment (MoCA) in Aging

OBJECTIVE

The present study aimed to determine whether specific cognitive domains part of the Montreal Cognitive Assessment (MoCA) are significantly lower in community-dwelling older adults with chronic pain compared with older adults without pain and whether these domains would be associated with self-reported pain, disability, and somatosensory function.

DESIGN

Secondary data analysis, cross-sectional.

SETTING

University of Florida.

SUBJECTS

Individuals over 60 years old enrolled in the Neuromodulatory Examination of Pain and mobility Across the Lifespan (NEPAL) study were included if they completed the MoCA and other study measures (n = 62). Most participants reported pain on most days during the past three months (63%).

METHODS

Subjects underwent a health assessment (HAS) and a quantitative sensory testing (QST) session. Health/medical history, cognitive function and self-reported pain measures were administered during the HAS. Mechanical and thermal detection, and thermal pain thresholds were assessed during the QST session.

RESULTS

Older adults with chronic pain had lower MoCA scores compared with controls on domains of executive function, attention, memory, and language (P < 0.05). The attention and language domains survived adjustments for age, sex, education, depression, and pain duration (P < 0.05). Attention was significantly associated with all pain characteristics including pain intensity and disability, while executive function was associated with mechanical detection (P < 0.05).

CONCLUSION

Our results support previous findings that individuals with chronic pain tend to show poorer cognitive functioning compared with pain-free controls in domains of attention and executive function. Our findings also extend these findings to community-dwelling older adults, who are already most vulnerable to age-related cognitive declines.

Brain gamma-aminobutyric acid, but not glutamine and glutamate levels are lower in older adults with chronic musculoskeletal pain: considerations by sex and brain location

INTRODUCTION AND OBJECTIVES

GABAergic and glutamatergic neurotransmitter systems are central to the pathophysiology of chronic pain and are equally affected by aging processes. We measured levels of frontal gamma-aminobutyric acid (GABA) and the combined resonance of glutamate and glutamine (Glx) in vivo using proton magnetic resonance spectroscopy (1H-MRS) to elucidate age-specific and pain-specific associations with clinical and experimental pain in older adults.

METHODS

Younger (18-24, n = 24) and older (60-94, n = 41) individuals part of a larger study (Neuromodulatory Examination of Pain and Mobility Across the Lifespan [NEPAL]) underwent questionnaires, quantitative sensory testing, and 1H-MRS Mescher-Garwood point-resolved spectroscopy to measure GABA and Glx levels in prefrontal and sensorimotor brain regions.

RESULTS

Older participants had significantly lower sensorimotor, but not prefrontal, GABA and Glx levels, compared with younger controls (P's < 0.05). Younger controls had significantly higher prefrontal and sensorimotor GABA, but not Glx, levels compared with older controls and older adults with chronic pain (P's < 0.05). Older males with chronic pain had significantly lower prefrontal GABA compared with older and younger male controls (P's < 0.05). Prefrontal GABA, but not Glx, was significantly associated with self-reported and experimental pain measures (P's < 0.05). Our results are the first to focus exclusively on age and pain differences in GABA and Glx including younger and older controls to elucidate aging and pain contributions to brain GABAergic and glutamatergic processes.

CONCLUSION

Evaluation of both the neuroinhibitory and neuroexcitatory mechanisms provide promising potential for improving both our understanding of the mechanisms of chronic pain in aging and opportunities for effective, individualized treatments.

Age Differences in Multimodal Quantitative Sensory Testing and Associations With Brain Volume

BACKGROUND AND OBJECTIVES

Somatosensory function is critical for successful aging. Prior studies have shown declines in somatosensory function with age; however, this may be affected by testing site, modality, and biobehavioral factors. While somatosensory function declines are associated with peripheral nervous system degradation, little is known regarding correlates with the central nervous system and brain structure in particular. The objectives of this study were to examine age-related declines in somatosensory function using innocuous and noxious stimuli, across 2 anatomical testing sites, with considerations for affect and cognitive function, and associations between somatosensory function and brain structure in older adults.

RESEARCH DESIGN AND METHODS

A cross-sectional analysis included 84 "younger" (n = 22, age range: 19-24 years) and "older" (n = 62, age range: 60-94 years) healthy adults who participated in the Neuromodulatory Examination of Pain and Mobility Across the Lifespan study. Participants were assessed on measures of somatosensory function (quantitative sensory testing), at 2 sites (metatarsal and thenar) using standardized procedures, and completed cognitive and psychological function measures and structural magnetic resonance imaging.

RESULTS

Significant age × test site interaction effects were observed for warmth detection (p = .018,η p 2 = 0.10) and heat pain thresholds (p = .014,η p 2 = 0.12). Main age effects were observed for mechanical, vibratory, cold, and warmth detection thresholds (ps < .05), with older adults displaying a loss of sensory function. Significant associations between somatosensory function and brain gray matter structure emerged in the right occipital region, the right temporal region, and the left pericallosum.

DISCUSSION AND IMPLICATIONS

Our findings indicate healthy older adults display alterations in sensory responses to innocuous and noxious stimuli compared to younger adults and, furthermore, these alterations are uniquely affected by anatomical site. These findings suggest a nonuniform decline in somatosensation in older adults, which may represent peripheral and central nervous system alterations part of aging processes.

Satisfaction, Usability, and Compliance With the Use of Smartwatches for Ecological Momentary Assessment of Knee Osteoarthritis Symptoms in Older Adults: Usability Study

Background

Smartwatches enable physicians to monitor symptoms in patients with knee osteoarthritis, their behavior, and their environment. Older adults experience fluctuations in their pain and related symptoms (mood, fatigue, and sleep quality) that smartwatches are ideally suited to capture remotely in a convenient manner.

Objective

The aim of this study was to evaluate satisfaction, usability, and compliance using the real-time, online assessment and mobility monitoring (ROAMM) mobile app designed for smartwatches for individuals with knee osteoarthritis.

Methods

Participants (N=28; mean age 73.2, SD 5.5 years; 70% female) with reported knee osteoarthritis were asked to wear a smartwatch with the ROAMM app installed. They were prompted to report their prior night’s sleep quality in the morning, followed by ecological momentary assessments (EMAs) of their pain, fatigue, mood, and activity in the morning, afternoon, and evening. Satisfaction, comfort, and usability were evaluated using a standardized questionnaire. Compliance with regard to answering EMAs was calculated after excluding time when the watch was not being worn for technical reasons (eg, while charging).

Results

A majority of participants reported that the text displayed was large enough to read (22/26, 85%), and all participants found it easy to enter ratings using the smartwatch. Approximately half of the participants found the smartwatch to be comfortable (14/26, 54%) and would consider wearing it as their personal watch (11/24, 46%). Most participants were satisfied with its battery charging system (20/26, 77%). A majority of participants (19/26, 73%) expressed their willingness to use the ROAMM app for a 1-year research study. The overall EMA compliance rate was 83% (2505/3036 responses). The compliance rate was lower among those not regularly wearing a wristwatch (10/26, 88% vs 16/26, 71%) and among those who found the text too small to read (4/26, 86% vs 22/26, 60%).

Conclusions

Older adults with knee osteoarthritis positively rated the ROAMM smartwatch app and were generally satisfied with the device. The high compliance rates coupled with the willingness to participate in a long-term study suggest that the ROAMM app is a viable approach to remotely collecting health symptoms and behaviors for both research and clinical endeavors.

Static and Dynamic Pain Sensitivity in Adults With Persistent Low Back Pain: Comparison to Healthy Controls and Associations With Movement-evoked Pain Versus Traditional Clinical Pain Measures

OBJECTIVES

Despite its impact, individual factors associated with persistent low back pain (LBP) remain poorly understood. This study investigated static and dynamic pain sensitivity in adults with persistent LBP versus pain-free controls; and investigated associations between pain sensitivity and 3 clinical pain measures: recalled, resting, and movement-evoked pain (MEP).

MATERIALS AND METHODS

A lifespan sample of 60 adults with persistent LBP and 30 age-matched/sex-matched controls completed 4 laboratory sessions. Static pain sensitivity (pressure pain threshold [PPT], heat pain threshold) and dynamic pain sensitivity (heat pain aftersensations [AS], temporal summation [TS] of second heat pain) were measured. Demographic and clinical factors collected were education, global cognition, and perceived health. Resting and recalled pain were measured via questionnaire, and MEP via the Back Performance Scale.

RESULTS

LBP participants demonstrated lower PPT remotely (hand; F1,84=5.34, P=0.024) and locally (low back; F1,84=9.55, P=0.003) and also had higher AS (F1,84=6.01, P=0.016). Neither static nor dynamic pain sensitivity were associated with recalled pain (P>0.05). However, static pain sensitivity (local PPT) explained an additional 9% variance in resting pain, while dynamic pain sensitivity (AS, TS) explained an additional 10% to 12% variance in MEP.

DISCUSSION

This study characterized pain sensitivity measures among individuals with persistent LBP and suggests static pain sensitivity plays a larger role in resting pain while dynamic pain sensitivity plays a larger role in MEP. Future studies will confirm these relationships and elucidate the extent to which changes in static or dynamic pain sensitivity predict or mediate clinical pain among adults with persistent LBP.

The Imperative for Racial Equality in Pain Science: A Way Forward

Racial equity is imperative to the future and integrity of scientific inquiry. In 2020, citizens of the United States (and globally) witnessed one of the most vile and egregious experiences of police brutality and systemic racism in recent history, the public execution of a Black American man. While some may isolate this and other similar events from influencing the scientific endeavors of pain researchers, events such as this can have a direct impact on the study, lived experience, and expression of pain in Black Americans. To truly understand the biopsychosocial effects of inequality and injustice on pain disparities, we must consider the unintended consequences that our current research approaches have in limiting the reliability and validity of scientific discovery. As we reflect on our current research practices in an effort to improve pain science, this perspective article discusses ways to initiate positive change in order to advance the science of pain in more equitable ways, not just for Black Americans, but for all individuals that identify as part of an underrepresented group. PERSPECTIVE: Elimination of inequities in pain care and research requires the identification, naming, and mitigation of systemic discriminatory and biased practices that limit our understanding of pain disparities. Now is the time to divest from traditional research methods and invest in equitable and innovative approaches to support pain researchers in advancing the science and improving the lives of people with pain.

Association of Hormonal Contraceptive Use with Headache and Temporomandibular Pain: The OPPERA Study

AIMS

To determine the relationship between hormonal contraceptive (HC) use and painful symptoms, particularly those associated with headache and painful temporomandibular disorders (TMD).

METHODS

Data from the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study were used. During the 2.5-year median follow-up period, quarterly health update (QHU) questionnaires were completed by 1,475 women aged 18 to 44 years who did not have TMD, menopause, hysterectomy, or hormone replacement therapy use at baseline. QHU questionnaires evaluated HC use, symptoms of headache and TMD, and pain of ≥ 1 day duration in 12 body regions. Participants who developed TMD symptoms were examined to classify clinical TMD. Headache symptoms were classified based on the International Classification of Headache Disorders 3 (ICHD-3). Associations between HC use and pain symptoms were analyzed using generalized estimating equations and Cox models.

RESULTS

HC use, endorsed in 33.7% of QHU questionnaires, was significantly associated with concurrent symptoms of TMD (odds ratio [OR]: 1.20, 95% CI: 1.06 to 1.35) and headache (OR: 1.26, 95% CI: 1.11 to 1.43). HC use was also significantly associated with concurrent pain of ≥ 1 day duration in the head (OR: 1.38, 95% CI: 1.16 to 1.63), face (OR: 1.44, 95% CI: 1.13 to 1.83), and legs (OR: 1.22, 95% CI: 1.01 to 1.47), but not elsewhere. Initiation of HC use was associated with increased odds of subsequent TMD symptoms (OR: 1.37, 95% CI: 1.13 to 1.66) and pain of ≥ 1 day in the head (OR: 1.37, 95% CI: 1.01 to 1.85). Discontinuing HC use was associated with lower odds of subsequent headache (OR: 0.82, 95% CI: 0.67 to 0.99). HC use was not significantly associated with subsequent onset of examiner-classified TMD.

CONCLUSION

These findings imply that HC influences craniofacial pain, and that this pain diminishes after cessation of HC use.

Uncontrolled Pain and Risk for Depression and Behavioral Symptoms in Residents With Dementia

OBJECTIVES

Limited cohort studies have assessed the association between uncontrolled pain and risk for behavioral and psychological symptoms of dementia (BPSDs). We conducted a longitudinal cohort study to examine whether associations exist between uncontrolled pain and risk for 2 common BPSDs-depression and behavioral symptoms-among long-term care (LTC) residents with Alzheimer disease and related dementia (ADRD).

DESIGN

This retrospective cohort study analyzed quarterly data from the 5% Medicare sample linked to Minimum Data Set (MDS) 3.0 between January 1, 2011, and December 31, 2015.

SETTING AND PARTICIPANTS

LTC residents aged 50 years or older with ADRD who had chronic pain and at least 2 quarterly MDS 3.0 assessments.

METHODS

LTC residents were followed up quarterly from first observed quarterly MDS 3.0 until first outcome event or last observed quarterly MDS 3.0. Uncontrolled pain was defined as numerical rating scale >4, verbal descriptor scale of moderate or severe pain, or ≥1 pain indicators on the Checklist of Nonverbal Pain Indicators. Depression was defined as ≥10 on the Patient Health Questionnaire 9; behavioral symptoms were defined as the presence of psychotic (delusions or hallucinations) or disruptive behaviors (rejection of care, or physical, verbal, or other aggressive behaviors). Generalized linear models (GLMs) with marginal structural modeling (MSM) stabilized weights were used to examine uncontrolled pain and outcome risk.

RESULTS

The incidence rate of depression and behavioral symptoms during follow-up was 9.4 and 23.1 per 100 resident-years, respectively. Results from the MSM-GLMs showed that LTC residents with uncontrolled pain had a higher risk than those with controlled pain for developing depression [hazard ratio 1.67, 95% confidence interval (CI) 1.54-1.81] and behavioral symptoms (hazard ratio 1.28, 95% CI 1.19-1.37).

CONCLUSIONS AND IMPLICATIONS

Uncontrolled pain was associated with elevated risk for depressive and behavioral symptoms in dementia, underscoring the importance of pain assessment and control among LTC residents with ADRD.

Sensory and Psychological Factors Predict Exercise-Induced Shoulder Injury Responses in a High-Risk Phenotype Cohort

Our prior studies identified a high-risk phenotype (ie, high pain sensitivity variant of the catechol-O-methyltransferase gene (Single Nucleotide Polymorphism [SNP] rs6269) and pain catastrophizing scores) for shoulder pain. The current study identified sensory and psychological predictors of heightened pain responses following exercise-induced shoulder injury. Healthy participants (N = 131) with the SNP rs6269 catechol-O-methyltransferase gene and Pain Catastrophizing Scale scores ≥5 underwent baseline sensory and psychological testing followed by an established shoulder fatigue protocol, to induce muscle injury. Movement-evoked pain, pain intensity, disability, and strength were assessed 24 hours postinjury. Demographic, sensory, and psychological variables were included as predictors in full and parsimonious models for each outcome. The highest variance explained was for the shoulder disability outcome (full model R2 = .20, parsimonious R2 = .13). In parsimonious models, the individual predictors identified were: 1) 1st pulse heat pain sensitivity for isometric shoulder movement-evoked pain and pain intensity; 2) pressure pain threshold for shoulder disability; 3) fear of pain for active shoulder movement-evoked pain and shoulder disability; and 4) depressive symptoms for shoulder strength. Findings indicate specific pain sensitivity and psychological measures may have additional prognostic value for self-reported disability within a high-risk phenotype. These findings should be tested in a clinical cohort for validation. PERSPECTIVE: The current study extends previous work by providing insight regarding how poor shoulder outcomes may develop within a high-risk phenotype. Specifically, 1st pulse heat pain sensitivity and pressure pain threshold were sensory measures, and fear of pain and depressive symptoms were psychological measures, that improved prediction of different shoulder outcomes.

A Mediation Appraisal of Catastrophizing, Pain-Related Outcomes, and Race in Adults With Knee Osteoarthritis

The current cross-sectional study investigates whether pain catastrophizing mediates the relationship between ethnicity/race and pain, disability and physical function in individuals with knee osteoarthritis. Furthermore, this study examined mediation at 2-year follow-up. Participants included 187 community-dwelling adults with unilateral or bilateral knee pain who screened positive for knee osteoarthritis. Participants completed several self-reported pain-related measures and pain catastrophizing subscale at baseline and 2-year follow-up. Non-Hispanic Black (NHB) adults reported greater pain, disability, and poorer functional performance compared to their non-Hispanic White (NHW) counterparts (Ps < .05). NHB adults also reported greater catastrophizing compared to NHW adults. Mediation analyses revealed that catastrophizing mediated the relationship between ethnicity/race and pain outcome measures. Specifically, NHB individuals reported significantly greater pain and disability, and exhibited lower levels of physical function, compared to NHW individuals, and these differences were mediated by higher levels of catastrophizing among NHB persons. Catastrophizing was a significant predictor of pain and disability 2-years later in both ethnic/race groups. These results suggest that pain catastrophizing is an important variable to consider in efforts to reduce ethnic/race group disparities in chronic pain. The findings are discussed in light of structural/systemic factors that may contribute to greater self-reports of pain catastrophizing among NHB individuals. PERSPECTIVE: The current study examines whether pain catastrophizing mediates the relationship between ethnicity/race and OA-related pain, disability, and functional impairment at baseline and during a 2-year follow-up period in non-Hispanic Black and non-Hispanic White adults with knee pain. These results point to the need for interventions that target pain catastrophizing.

Clinical, psychological, and sensory characteristics associated with headache attributed to temporomandibular disorder in people with chronic myogenous temporomandibular disorder and primary headaches

Background

Headache attributed to Temporomandibular Disorder (HATMD) is a secondary headache that may have features resulting in diagnostic overlap with primary headaches, namely, tension-type (TTH) or migraine. This cross-sectional study of people with both chronic myogenous TMD and primary headaches evaluated characteristics associated with HATMD.

Methods

From a clinical trial of adults, baseline data were used from a subset with diagnoses of both TMD myalgia according to the Diagnostic Criteria for TMD (DC/TMD) and TTH or migraine according to the International Classification of Headache Disorders, 3rd edition. HATMD was classified based on the DC/TMD. Questionnaires and examinations evaluated 42 characteristics of facial pain, headache, general health, psychological distress, and experimental pain sensitivity. Univariate regression models quantified the associations of each characteristic with HATMD (present versus absent), headache type (TTH versus migraine), and their interaction in a factorial design. Multivariable lasso regression identified the most important predictors of HATMD.

Results

Of 185 participants, 114 (61.6%) had HATMD, while the numbers with TTH (n = 98, 53.0%) and migraine (n = 87, 47.0%) were similar. HATMD was more likely among migraineurs (61/87 = 70.1%) than participants with TTH (53/98 = 54.1%; odds ratio = 2.0; 95%CL = 1.1, 3.7). In univariate analyses, characteristics associated with HATMD included pain-free jaw opening and examination-evoked pain in masticatory muscles and temporomandibular joints (TMJ) as well as frequency and impact of headache, but not frequency or impact of facial pain. Lowered blood pressure but not psychological or sensory characteristics was associated with HATMD. Multiple characteristics of facial pain, headache, general health, and psychological distress differed between TTH or migraine groups. Few interactions were observed, demonstrating that most characteristics’ associations with HATMD were consistent in TTH and migraine groups. The lasso model identified headache frequency and examination-evoked muscle pain as the most important predictors of HATMD.

Conclusions

HATMD is highly prevalent among patients with chronic myogenous TMD and headaches and often presents as migraine. In contrast to primary headaches, HATMD is associated with higher headache frequency and examination-evoked masticatory muscle pain, but with surprisingly few measures of facial pain, general health, and psychological distress. A better understanding of HATMD is necessary for developing targeted strategies for its management.

Trial identification and registration

SOPPRANO; NCT02437383. Registered May 7, 2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01255-1.

Forty-two Million Ways to Describe Pain: Topic Modeling of 200,000 PubMed Pain-Related Abstracts Using Natural Language Processing and Deep Learning-Based Text Generation

OBJECTIVE

Recent efforts to update the definitions and taxonomic structure of concepts related to pain have revealed opportunities to better quantify topics of existing pain research subject areas.

METHODS

Here, we apply basic natural language processing (NLP) analyses on a corpus of >200,000 abstracts published on PubMed under the medical subject heading (MeSH) of "pain" to quantify the topics, content, and themes on pain-related research dating back to the 1940s.

RESULTS

The most common stemmed terms included "pain" (601,122 occurrences), "patient" (508,064 occurrences), and "studi-" (208,839 occurrences). Contrarily, terms with the highest term frequency-inverse document frequency included "tmd" (6.21), "qol" (6.01), and "endometriosis" (5.94). Using the vector-embedded model of term definitions available via the "word2vec" technique, the most similar terms to "pain" included "discomfort," "symptom," and "pain-related." For the term "acute," the most similar terms in the word2vec vector space included "nonspecific," "vaso-occlusive," and "subacute"; for the term "chronic," the most similar terms included "persistent," "longstanding," and "long-standing." Topic modeling via Latent Dirichlet analysis identified peak coherence (0.49) at 40 topics. Network analysis of these topic models identified three topics that were outliers from the core cluster, two of which pertained to women's health and obstetrics and were closely connected to one another, yet considered distant from the third outlier pertaining to age. A deep learning-based gated recurrent units abstract generation model successfully synthesized several unique abstracts with varying levels of believability, with special attention and some confusion at lower temperatures to the roles of placebo in randomized controlled trials.

CONCLUSIONS

Quantitative NLP models of published abstracts pertaining to pain may point to trends and gaps within pain research communities.

Knee pain trajectories over 18 months in non-Hispanic Black and non-Hispanic White adults with or at risk for knee osteoarthritis

BACKGROUND

Pain is the hallmark symptom of knee osteoarthritis (OA), and varies widely across individuals. Previous research has demonstrated both fluctuating and stable pain trajectories in knee OA using various time periods. Changes in pain assessed quarterly (i.e. 3-month intervals) in knee OA are relatively unknown. The current study aimed to investigate temporal variations in pain over a one and a half year period (18 months) based on quarterly characteristic pain assessments, and to examine differences in pain patterns by sociodemographic and baseline pain characteristics.

METHODS

The sample included a prospective cohort of 188 participants (mean age 58 years; 63% female; 52% non-Hispanic Black) with or at risk for knee OA from an ongoing multisite investigation of ethnic/race group differences. Knee pain intensity was self-reported at baseline and quarterly over an18-month period. Baseline pain assessment also included frequency, duration, and total number of pain sites. Group-based trajectory modeling was used to identify distinct pain trajectories. Multinomial logistic regression was used to examine associations between sociodemographic characteristics, risk factors, and pain trajectory groups.

RESULTS

Pain trajectories were relatively stable among a sample of adults with knee pain. Four distinct pain trajectories emerged in the overall sample, with the largest proportion of participants (35.1%) classified in the moderate-high pain group. There were significant relationships between age, education, income, ethnicity/race and trajectory group; with younger, less educated, lower income, and non-Hispanic Black participants had a greater representation in the highest pain trajectory group.

CONCLUSIONS

Pain remained stable across a one and a half-year period in adults with or at risk for knee osteoarthritis, based on quarterly assessments. Certain sociodemographic variables (e.g. ethnicity/race, education, income, age) may contribute to an increased risk of experiencing greater pain.

Phenotypic profile clustering pragmatically identifies diagnostically and mechanistically informative subgroups of chronic pain patients

ABSTRACT

Traditional classification and prognostic approaches for chronic pain conditions focus primarily on anatomically based clinical characteristics not based on underlying biopsychosocial factors contributing to perception of clinical pain and future pain trajectories. Using a supervised clustering approach in a cohort of temporomandibular disorder cases and controls from the Orofacial Pain: Prospective Evaluation and Risk Assessment study, we recently developed and validated a rapid algorithm (ROPA) to pragmatically classify chronic pain patients into 3 groups that differed in clinical pain report, biopsychosocial profiles, functional limitations, and comorbid conditions. The present aim was to examine the generalizability of this clustering procedure in 2 additional cohorts: a cohort of patients with chronic overlapping pain conditions (Complex Persistent Pain Conditions study) and a real-world clinical population of patients seeking treatment at duke innovative pain therapies. In each cohort, we applied a ROPA for cluster prediction, which requires only 4 input variables: pressure pain threshold and anxiety, depression, and somatization scales. In both complex persistent pain condition and duke innovative pain therapies, we distinguished 3 clusters, including one with more severe clinical characteristics and psychological distress. We observed strong concordance with observed cluster solutions, indicating the ROPA method allows for reliable subtyping of clinical populations with minimal patient burden. The ROPA clustering algorithm represents a rapid and valid stratification tool independent of anatomic diagnosis. ROPA holds promise in classifying patients based on pathophysiological mechanisms rather than structural or anatomical diagnoses. As such, this method of classifying patients will facilitate personalized pain medicine for patients with chronic pain.

Quality of opioid prescribing in older adults with or without Alzheimer disease and related dementia

Background

Pain is common among individuals with Alzheimer’s disease and related dementias (ADRD), and use of opioids has been increasing over the last decade. Yet, it is unclear to what extent opioids are appropriately prescribed for patients with ADRD and whether the appropriateness of opioid prescribing differs by ADRD status. The objective of this study is to compare the quality of opioid prescribing among patients with or without ADRD who have chronic noncancer pain.

Methods

A nationally representative cohort study of Medicare beneficiaries aged 50 years or older who had chronic pain but who had no cancer, hospice, or palliative care from 2011 to 2015. Four indicators of potentially inappropriate opioid prescribing were measured in patients residing in communities (75,258 patients with and 435,870 patients without ADRD); five indicators were assessed in patients in nursing homes (NHs) (37,117 patients with and 5128 patients without ADRD). Each indicator was calculated as the proportion of eligible patients with inappropriate opioid prescribing in the year after a chronic pain diagnosis. Differences in proportions between ADRD and non-ADRD groups were estimated using a generalized linear model adjusting for covariates through inverse probability weighting.

Results

Patients with ADRD versus those without had higher concurrent use of opioids and central nervous system–active drugs (community 44.1% vs 33.3%; NH 58.8% vs 54.1%, both P < 0.001) and no opioids or scheduled pain medications for moderate or severe pain (NH 60.1% vs 52.5%, P < 0.001). The ADRD versus non-ADRD group had higher use of long-term opioids for treating neuropathic pain in communities (21.7% vs 19.5%, P = 0.003) but lower use in NHs (26.9% vs 36.0%, P < 0.001). Use of strong or high-dose opioids when naive to opioids (community 1.5% vs 2.8%; NH 2.5% vs 3.5%) and use of contraindicated opioids (community 0.08% vs 0.12%; NH 0.05% vs 0.21%) were rare for either group.

Conclusion

Potential inappropriate opioid prescribing in 2 areas of pain care was more common among patients with ADRD than among patients without ADRD in community or NH settings. Further studies aimed at understanding the factors and effects associated with opioid prescribing patterns that deviate from guidelines are warranted.

A hybrid implementation-effectiveness randomized trial of CYP2D6-guided postoperative pain management

PURPOSE

Cytochrome P450 2D6 (CYP2D6) genotype-guided opioid prescribing is limited. The purpose of this type 2 hybrid implementation-effectiveness trial was to evaluate the feasibility of clinically implementing CYP2D6-guided postsurgical pain management and determine that such an approach did not worsen pain control.

METHODS

Adults undergoing total joint arthroplasty were randomized 2:1 to genotype-guided or usual pain management. For participants in the genotype-guided arm with a CYP2D6 poor (PM), intermediate (IM), or ultrarapid (UM) metabolizer phenotype, recommendations were to avoid hydrocodone, tramadol, codeine, and oxycodone. The primary endpoints were feasibility metrics and opioid use; pain intensity was a secondary endpoint. Effectiveness outcomes were collected 2 weeks postsurgery.

RESULTS

Of 282 patients approached, 260 (92%) agreed to participate. In the genotype-guided arm, 20% had a high-risk (IM/PM/UM) phenotype, of whom 72% received an alternative opioid versus 0% of usual care participants (p < 0.001). In an exploratory analysis, there was less opioid consumption (200 [104-280] vs. 230 [133-350] morphine milligram equivalents; p = 0.047) and similar pain intensity (2.6 ± 0.8 vs. 2.5 ± 0.7; p = 0.638) in the genotype-guided vs. usual care arm, respectively.

CONCLUSION

Implementing CYP2D6 to guide postoperative pain management is feasible and may lead to lower opioid use without compromising pain control.

Topical Review: Examining Multidomain Pain Resilience in Late Adolescents and Young Adults

OBJECTIVE

Upwards of 14% of late adolescents and young adults (AYAs) experience chronic pain; however, limited research has focused on factors specifically influencing late AYAs as they transition to adulthood. In this topical review, we propose a conceptual model of multidomain pain resilience (MDPR) in late AYAs with chronic pain that extends existing pain resilience literature, including the Ecological Resilience-Risk Model for Pediatric Chronic Pain.

METHOD

A conceptual framework for MDPR in late AYAs was developed from the existing literature on resilience in young people with chronic pain. Gaps in knowledge specific to late AYAs are identified, and relevant research examining MDPR in adults with pain are summarized to inform applications of this concept to youth as they transition to adulthood.

RESULTS

Few studies have explored resilience factors in pediatric pain. Of note, these endeavors have largely neglected late adolescence and young adulthood, despite unique considerations germane to this crucial developmental period. Existing research has also focused exclusively on assessing resilience as a unitary, rather than a multidimensional construct. Although limited, MDPR has been examined in midlife and older adults with chronic pain, highlighting the need to expand prior models of pain resilience and extend these principles to emerging adulthood.

CONCLUSIONS

Understanding MDPR in late AYAs with chronic pain may provide insights regarding measurable and modifiable resilience factors (e.g., adaptive and personal resources) that promote healthy pain-related outcomes (e.g., reduced pain and enhanced physical functioning) and optimize prevention and/or treatment strategies for this group.

Multi-ethnic GWAS and meta-analysis of sleep quality identify MPP6 as a novel gene that functions in sleep center neurons

Poor sleep quality can have harmful health consequences. Although many aspects of sleep are heritable, the understandings of genetic factors involved in its physiology remain limited. Here, we performed a genome-wide association study (GWAS) using the Pittsburgh Sleep Quality Index (PSQI) in a multi-ethnic discovery cohort (n = 2868) and found two novel genome-wide loci on chromosomes 2 and 7 associated with global sleep quality. A meta-analysis in 12 independent cohorts (100 000 individuals) replicated the association on chromosome 7 between NPY and MPP6. While NPY is an important sleep gene, we tested for an independent functional role of MPP6. Expression data showed an association of this locus with both NPY and MPP6 mRNA levels in brain tissues. Moreover, knockdown of an orthologue of MPP6 in Drosophila melanogaster sleep center neurons resulted in decreased sleep duration. With convergent evidence, we describe a new locus impacting human variability in sleep quality through known NPY and novel MPP6 sleep genes.

Race Differences in Resilience Among Older Adults with Chronic Low Back Pain

Introduction

Racial minorities are disproportionally affected by pain. Compared to non-Hispanic Whites (NHWs), non-Hispanic Blacks (NHBs) report higher pain intensity, greater pain-related disability, and higher levels of mood disturbance. While risk factors contribute to these disparities, little is known regarding how sources of resilience influence these differences, despite the growing body of research supporting the protective role of resilience in pain and disability among older adults with chronic pain. The current study examined the association between psychological resilience and pain, and the moderating role of race across these relationships in older adults with chronic low back pain (cLBP).

Methods

This is a secondary analysis of the Adaptability and Resilience in Aging Adults (ARIAA). Participants completed measures of resilience (ie, gratitude, trait resilience, emotional support), as well as a performance-based measure assessing lower-extremity function and movement-evoked pain.

Results

There were 45 participants that identified as non-Hispanic White (NHW) and 15 participants that identified as non-Hispanic Black (NHB). Race was a significant correlate of pain outcomes with NHBs reporting greater movement-evoked pain (r = 0.27) than NHWs. After controlling for relevant sociodemographic characteristics, measures of movement-evoked pain were similar across both racial groups, F (1, 48) = 0.31, p = 0.57. Moderation analyses revealed that higher levels of gratitude (b = −1.23, p = 0.02) and trait resilience (b = −10.99, p = 0.02) were protective against movement-evoked pain in NHWs. In contrast, higher levels of gratitude were associated with lower functional performance in NHBs (b = −0.13, p =0.02).

Discussion

These findings highlight racial differences in the relationship between resilience and pain-related outcomes among older adults with cLBP. Future studies should examine the potential benefits of targeted interventions that improve resilience and ameliorate pain disparities among racial minorities.

Predicting long-term postsurgical pain by examining the evolution of acute pain

BACKGROUND

Increased acute postoperative pain intensity has been associated with the development of persistent postsurgical pain (PPP) in mechanistic and clinical investigations, but it remains unclear which aspects of acute pain explain this linkage.

METHODS

We analysed clinical postoperative pain intensity assessments using symbolic aggregate approximations (SAX), a graphical way of representing changes between pain states from one patient evaluation to the next, to visualize and understand how pain intensity changes across sequential assessments are associated with the intensity of postoperative pain at 1 (M1) and 6 (M6) months after surgery. SAX-based acute pain transition patterns were compared using cosine similarity, which indicates the degree to which patterns mirror each other.

RESULTS

This single-centre prospective cohort study included 364 subjects. Patterns of acute postoperative pain sequential transitions differed between the 'None' and 'Severe' outcomes at M1 (cosine similarity 0.44) and M6 (cosine similarity 0.49). Stratifications of M6 outcomes by preoperative pain intensity, sex, age group, surgery type and catastrophising showed significant heterogeneity of pain transition patterns within and across strata. Severe-to-severe acute pain transitions were common, but not exclusive, in patients with moderate or severe pain intensity at M6.

CONCLUSIONS

Clinically, these results suggest that individual pain-state transitions, even within patient or procedural strata associated with PPP, may not alone offer good predictive information regarding PPP. Longitudinal observation in the immediate postoperative period and consideration of patient- and surgery-specific factors may help indicate which patients are at increased risk of PPP.

SIGNIFICANCE

Symbolic aggregate approximations of clinically obtained, acute postoperative pain intraday time series identify different motifs in patients suffering moderate to severe pain 6 months after surgery.

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.

Effect of comorbid migraine on propranolol efficacy for painful TMD in a randomized controlled trial

Introduction

The migraine-preventive drug propranolol is efficacious in reducing pain from temporomandibular disorder, suggesting potential modifying or mediating effects of comorbid migraine.

Methods

In this randomized controlled trial, myofascial temporomandibular disorder patients were treated with propranolol or placebo for 9 weeks. The primary endpoint was change in a facial pain index derived from daily symptom diaries. Linear and logistic regression models tested for a migraine × treatment-group interaction in reducing facial pain index. Counterfactual models explored changes in headache impact and heart rate as mediators of propranolol's efficacy.

Results

Propranolol's efficacy in reducing facial pain index was greater among the 104 migraineurs than the 95 non-migraineurs: For example, for the binary ≥ 30% reduction in facial pain index, odds ratios were 3.3 (95% confidence limits: 1.4, 8.1) versus 1.3 (0.5, 3.2), respectively, although the interaction was statistically non-significant (p = 0.139). Cumulative response curves confirmed greater efficacy for migraineurs than non-migraineurs (differences in area under the curve 26% and 6%, respectively; p = 0.081). While 9% of the treatment effect was mediated by reduced headache impact, 46% was mediated by reduced heart rate.

Conclusions

Propranolol was more efficacious in reducing temporomandibular disorder pain among migraineurs than non-migraineurs, with more of the effect mediated by reduced heart rate than by reduced headache impact.

Study identification and registration

SOPPRANO; NCT02437383; https://clinicaltrials.gov/ct2/show/NCT02437383

Neuropathic-Like Pain Symptoms in a Community-Dwelling Sample with or at Risk for Knee Osteoarthritis

OBJECTIVE

To characterize neuropathic-like pain among individuals with or at risk for knee osteoarthritis.

SUBJECTS

One hundred eighty-four individuals who self-identified as non-Hispanic black or non-Hispanic white and presented with unilateral or bilateral knee pain.

DESIGN

Neuropathic-like pain was assessed using the painDETECT, and those with high vs low neuropathic-like pain were compared on clinical pain, psychological symptoms, physical function, and quantitative sensory testing. Analyses were unadjusted, partially and fully adjusted for relevant covariates.

RESULTS

Thirty-two (17.4%) participants reported experiencing neuropathic-like pain features above the painDETECT clinical cut-score. The neuropathic-like pain group reported significantly greater pain severity on all measures of clinical pain and higher levels of psychological symptoms when fully adjusted for covariates, but no differences emerged for disability and lower extremity function. The neuropathic-like pain group also reported greater overall heat pain ratings during the heat pain threshold and increased temporal summation of heat pain in the fully adjusted model. Additionally, those with neuropathic-like pain symptoms reported greater painful after-sensations following heat pain temporal summation in all analyses. No significant group differences in pressure pain threshold emerged at any of the testing sites. In contrast, temporal summation of mechanical pain was significantly greater at both the index knee and the ipsilateral hand for the neuropathic-like pain group in all analyses.

CONCLUSIONS

Participants with or at risk for knee osteoarthritis who reported high neuropathic-like pain experienced significantly greater clinical pain and increased heat and mechanical temporal summation at the index knee and other body sites tested, suggesting central sensitization.

The Temporal Relationship Between Ecological Pain and Life-Space Mobility in Older Adults With Knee Osteoarthritis: A Smartwatch-Based Demonstration Study

Background

Older adults who experience pain are more likely to reduce their community and life-space mobility (ie, the usual range of places in an environment in which a person engages). However, there is significant day-to-day variability in pain experiences that offer unique insights into the consequences on life-space mobility, which are not well understood. This variability is complex and cannot be captured with traditional recall-based pain surveys. As a solution, ecological momentary assessments record repeated pain experiences throughout the day in the natural environment.

Objective

The aim of this study was to examine the temporal association between ecological momentary assessments of pain and GPS metrics in older adults with symptomatic knee osteoarthritis by using a smartwatch platform called Real-time Online Assessment and Mobility Monitor.

Methods

Participants (n=19, mean 73.1 years, SD 4.8; female: 13/19, 68%; male: 6/19, 32%) wore a smartwatch for a mean period of 13.16 days (SD 2.94). Participants were prompted in their natural environment about their pain intensity (range 0-10) at random time windows in the morning, afternoon, and evening. GPS coordinates were collected at 15-minute intervals and aggregated each day into excursion, ellipsoid, clustering, and trip frequency features. Pain intensity ratings were averaged across time windows for each day. A random effects model was used to investigate the within and between-person effects.

Results

The daily mean pain intensities reported by participants ranged between 0 and 8 with 40% reporting intensities ≥2. The within-person associations between pain intensity and GPS features were more likely to be statistically significant than those observed between persons. Within-person pain intensity was significantly associated with excursion size, and others (excursion span, total distance, and ellipse major axis) showed a statistical trend (excursion span: P=.08; total distance: P=.07; ellipse major axis: P=.07). Each point increase in the mean pain intensity was associated with a 3.06 km decrease in excursion size, 2.89 km decrease in excursion span, 5.71 km decrease total distance travelled per day, 31.4 km² decrease in ellipse area, 0.47 km decrease ellipse minor axis, and 3.64 km decrease in ellipse major axis. While not statistically significant, the point estimates for number of clusters (P=.73), frequency of trips (P=.81), and homestay (P=.15) were positively associated with pain intensity, and entropy (P=.99) was negatively associated with pain intensity.

Conclusions

In this demonstration study, higher intensity knee pain in older adults was associated with lower life-space mobility. Results demonstrate that a custom-designed smartwatch platform is effective at simultaneously collecting rich information about ecological pain and life-space mobility. Such smart tools are expected to be important for remote health interventions that harness the variability in pain symptoms while understanding their impact on life-space mobility.