Rheumatoid arthritis in American Indians and Alaska Natives: a review of the literature

Therapeutic interception in individuals at risk of rheumatoid arthritis to prevent clinically impactful disease

Multiple clinical trials for rheumatoid arthritis (RA) prevention have been completed. Here, we set out to report on the lessons learnt from these studies. Researchers who conducted RA prevention trials shared the background, rationale, approach and outcomes and evaluated the lessons learnt to inform the next generation of RA prevention trials. Individuals at risk of RA can be identified through population screening, referrals to musculoskeletal programmes and by recognition of arthralgia suspicious for RA. Clinical trials in individuals at risk for future clinical RA have demonstrated that limited courses of corticosteroids, atorvastatin and hydroxychloroquine do not alter incidence rates of clinical RA; however, rituximab delays clinical RA onset, and methotrexate has transient effects in individuals who are anticitrullinated protein antibody-positive with subclinical joint inflammation identified by imaging. Abatacept delays clinical RA onset but does not fully prevent onset of RA after treatment cessation. Additionally, subclinical joint inflammation and symptoms appear responsive to interventions such as methotrexate and abatacept. To advance prevention, next steps include building networks of individuals at risk for RA, to improve risk stratification for future RA and to understand the biological mechanisms of RA development, including potential endotypes of disease, which can be targeted for prevention, thus adopting a more precision-based approach. Future trials should focus on interceptions aimed at preventing clinical RA onset and which treat existing symptoms and imaging-defined subclinical inflammation. These trials may include advanced designs (eg, adaptive) and should be combined with mechanistic studies to further define pathophysiological drivers of disease development.

Rheumatoid Arthritis: The Continuum of Disease and Strategies for Prediction, Early Intervention, and Prevention

Rheumatoid arthritis (RA) is known to include a pre-RA stage that can be defined as the presence of familial or genetic risk factors, biomarker abnormalities (eg, anticitrullinated protein antibodies [ACPA]), symptoms, and even abnormal imaging findings prior to the development of the onset of clinical RA with inflammatory arthritis that is apparent on physical examination. Indeed, there are multiple completed or ongoing retrospective case-control as well as prospective observational studies to identify the key biologic drivers of disease. Further, building on the predictive ability of combinations of biomarkers, symptoms, and imaging for future RA, there are multiple clinical trials completed, underway, or in development to identify approaches that may prevent, delay, or ameliorate future clinical RA in at-risk individuals. Importantly, however, although an effective preventive intervention has not yet been identified, at-risk individuals are being increasingly identified in clinical care; this presents a challenge of how to manage these individuals in clinical practice. This review will discuss the current understanding of the biology and natural history of RA development, nomenclature, and current models for prediction of future RA, as well as evaluate the current and ongoing clinical prevention trials with the overall goal to provide insights into the challenges and opportunities in the field of RA prevention. Moreover, this review will provide up-to-date options for clinical management of individuals at risk for RA.

Healthcare segregation in orthopedic surgery: A statewide analysis of American Indian and Alaska Native patients

Significant health disparities have been described for American Indian and Alaska Native (AIAN) patients undergoing various surgical procedures, however, research into healthcare segregation within orthopedic surgery has been limited. In this study, our purpose was to assess if AIAN patients were more likely to be treated by lower-volume surgeons and at lower-volume hospitals. AIAN and White patients who underwent one of four common orthopedic procedures (knee or hip arthroplasty, femur or tibia repair) were identified from a Washington state inpatient database. Demographic, socioeconomic, geographic, and procedure data were surveyed, and volumetric thresholds were established for lower versus higher volume surgeons and hospitals. Adjusted odds ratios were calculated for AIAN patients receiving care from a lower volume surgeon or hospital, including covariates for patient demographics, geographic, and socioeconomic status. AIAN patients were more likely to receive care from a lower-volume surgeon for all procedures except tibial repair. Adjusted odds ratios of 1.53 (95% confidence interval [CI]: 1.22, 1.92) and 1.68 (95% CI: 1.26, 2.21) were found for AIAN patients receiving knee or hip arthroplasty from a lower volume surgeon, respectively. There was no strong evidence of AIAN patients being more likely to receive care at a lower-volume hospital. Finally, AIAN patients having knee arthroplasty at a higher volume hospital were more likely to have their surgery performed by a lower volume surgeon. These data suggest that there may be significant healthcare segregation among AIAN patients across common orthopedic surgical procedures.

Racial and Ethnic Distribution of Rheumatic Diseases in Health Systems of the National Patient-Centered Clinical Research Network

OBJECTIVE

To evaluate the relative prevalence of 8 rheumatic and musculoskeletal diseases (RMDs) across racial and ethnic groups within the National Patient-Centered Clinical Research Network (PCORnet).

METHODS

Electronic health records from participating PCORnet institutions and systems from January 1, 2013, to December 31, 2018, were used to identify adult patients with ≥ 2 diagnosis codes for rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), osteoporosis (OP), granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), eosinophilic granulomatosis with polyangiitis (EGPA), giant cell arteritis (GCA), and Takayasu arteritis (TAK). Among those with race and ethnicity data available, we compared prevalence of RMDs by race and ethnicity.

RESULTS

Data from 28,059,546 patients were available for analysis. RA was more common in patients who were American Indian or Alaska Native vs White, with a prevalence of 11.57 vs 10.11/1000 (odds ratio [OR] 1.15, 95% CI 1.09-1.22). SLE was more common in patients who were Black or African American (6.73/1000), American Indian or Alaska Native (3.82/1000), and Asian (3.39/1000) vs White (2.80/1000; OR 2.43, 95% CI 2.39-2.46; OR 1.39, 95% CI 1.25-1.53; OR 1.26, 95% CI 1.21-1.31, respectively). SLE was more common in patients who were Hispanic vs non-Hispanic (prevalence 3.93 vs 3.45/1000, OR 1.14, 95% CI 1.12-1.16). TAK was more common in patients who were Asian vs White (prevalence 0.05 vs 0.04/1000, OR 1.43, 95% CI 1.00-2.03). OP, RA, and the vasculitides were all more common in patients who were White vs Black or African American.

CONCLUSION

These data provide important information on the prevalence of RMDs by race and ethnicity in the United States. PCORnet can be used as a reliable data source to study RMDs within a large representative population.

C-Terminal Region of Caveolin-3 Contains a Stretch of Amino Acid Residues Capable of Diminishing Symptoms of Experimental Autoimmune Encephalomyelitis but Not Rheumatoid Arthritis Modeled in Rats

A short synthetic peptide from the C-terminal part of the caveolin-3 structure was tested for experimental autoimmune encephalomyelitis (EAE) treatment in rats. The structure-function similarity established between the novel synthetic peptide of pCav3 and the well-known immunomodulator immunocortin determined pCav3's ability to reduce EAE symptoms in Dark Agouti (DA) rats injected with pCav3 (500 µg/kg). pCav3 was found to interfere with the proliferation of lymphocytes extracted from the LNs of DA rats primed with homogenate injection, with IC50 = 0.42 μM (2.35 mcg/mL). pCav3 affected EAE in a very similar manner as immunocortin. The high degree of homology between the amino acid sequences of pCav3 and immunocortin corresponded well with the therapeutic activities of both peptides, as demonstrated on EAE. The latter peptide, possessing a homologous structure to pCav3, was also tested on EAE to explore whether there were structural restrictions between these peptides implied by the MHC-involved cell machinery. Consequently, immunocortin was further examined with a different autoimmune disease model, collagen-induced arthritis (CIA), established in Sprague-Dawley rats. CIA was established using an intentionally different genetic platform than EAE. Based on the results, it was concluded that the effectiveness of pCav3 and immunocortin peptides in EAE rat model was almost identical, but differed in the rat model of rheumatoid arthritis; thus, efficacy may be sensitive to the MHC type of animals used to establish the autoimmune disease model.

Inappropriate treatment response to DMARDs: A pathway to difficult-to-treat rheumatoid arthritis

In recent years, difficult-to-treat rheumatoid arthritis (D2T RA) has attracted significant attention from rheumatologists due to its poor treatment response and the persistent symptoms or signs experienced by patients. The therapeutic demands of patients with D2T RA are not properly met due to unclear pathogenic causes and a lack of high-quality data for current treatment options, creating considerable management difficulties with this patient population. This review describes the clinical challenges associated with disease-modifying antirheumatic drugs (DMARDs) and explores contributing factors associated with inappropriate response to DMARDs that may lead to D2T RA and related immunological dysregulation. It is now understood that D2T RA is a highly heterogeneous pathological status that involves multiple factors. These factors include but are not limited to genetics, environment, immunogenicity, comorbidities, adverse drug reactions, inappropriate drug application, poor adherence, and socioeconomic status. Besides, these factors may manifest in the selection and utilization of specific DMARDs, either individually or in combination, thereby contributing to inadequate treatment response. Finding these variables may offer hints for enhancing DMARD therapy plans and bettering the condition of D2T RA patients.

Unique Serum Immune Phenotypes and Stratification of Oklahoma Native American Rheumatic Disease Patients

OBJECTIVE

Native American (NA) populations have higher rates of rheumatic disease and present with overlapping disease symptoms and nontraditional serologic features, thus presenting an urgent need for better biomarkers in NA diagnostics. This study used a machine learning approach to identify immune signatures that more effectively stratify NA patients with rheumatic disease.

METHODS

Adult NA patients with autoantibody-positive (AAB+) rheumatoid arthritis (RA; n = 28), autoantibody negative (AAB-) RA (n = 18), systemic autoimmune rheumatic disease (n = 28), arthralgia/osteoarthritis (n = 28), or polyarthritis/undifferentiated connective tissue disease (n = 28), and control patients (n = 28) provided serum samples for cytokine, chemokine, and AAB assessment. Random forest clustering and soluble mediator groups were used to identify patients and control patients with similar biologic signatures. The American College of Rheumatology criteria specific for systemic disease and RA identified differences in disease manifestations across clusters.

RESULTS

Serum soluble mediators were not homogenous between different NA rheumatic disease diagnostic groups, reflecting the heterogeneity of autoimmune diseases. Clustering by serum biomarkers created 5 analogous immune phenotypes. Soluble mediators and pathways associated with chronic inflammation and involvement of the innate, B cell, T follicular helper cell, and interferon-associated pathways, along with regulatory signatures, distinguished the 5 immune signatures among patients. Select clinical features were associated with individual immune profiles. Patients with low inflammatory and higher regulatory signatures were more likely to have few clinical manifestations, whereas those with T cell pathway involvement had more arthritis.

CONCLUSION

Serum protein signatures distinguished NA patients with rheumatic disease into distinct immune subsets. Following these immune profiles over time may assist with earlier diagnoses and help guide more personalized treatment approaches.

Personalized medicine in rheumatoid arthritis: Combining biomarkers and patient preferences to guide therapeutic decisions

The last few decades have seen major therapeutic advancements in rheumatoid arthritis (RA) therapeutics. New disease-modifying antirheumatic drugs (DMARDs) have continued to emerge, creating more choices for people. However, no therapeutic works for all patients. Each has its own inherent benefits, risks, costs, dosing, and monitoring considerations. In parallel, there has been a focus on personalized medicine initiatives that tailor therapeutic decisions to patients based on their unique characteristics or biomarkers. Personalized effect estimates require an understanding of a patient's baseline probability of response to treatment and data on the comparative effectiveness of the available treatments. However, even if accurate risk prediction models are available, trade-offs often still need to be made between treatments. In this paper, we review the history of RA therapeutics and progress that has been made toward personalized risk predictive models for DMARDs, outlining where knowledge gaps still exist. We further review why patient preferences play a key role in a holistic view of personalized medicine and how this links with shared decision-making. We argue that a "preference misdiagnosis" may be equally important as a medical misdiagnosis but is often overlooked.

Global epidemiology of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that predominantly affects the joints. The prevalence of RA varies globally, with generally a higher prevalence in industrialized countries, which may be explained by exposures to environmental risk factors, but also by genetic factors, differing demographics and under-reporting in other parts of the world. Over the past three decades, strong trends of the declining severity of RA probably reflect changes in treatment paradigms and overall better management of the disease. Other trends include increasing RA prevalence. Common risk factors for RA include both modifiable lifestyle-associated variables and non-modifiable features, such as genetics and sex. A better understanding of the natural history of RA, and of the factors that contribute to the development of RA in specific populations, might lead to the introduction of specific prevention strategies for this debilitating disease.

Health inequities in the rheumatic diseases of childhood

PURPOSE OF REVIEW

To describe differences in disease manifestations and outcomes in pediatric rheumatic diseases as they occur in non-European-descended populations in North America.

RECENT FINDINGS

Differences in disease prevalence, clinical phenotypes, disease course, and outcomes have been described across the spectrum of pediatric-onset rheumatic diseases. Although these differences are commonly explained by differences in genetic risk or access to tertiary healthcare facilities, our emerging understanding of the immunobiology of historical/ongoing trauma suggest a more complex explanation for these observed differences.

SUMMARY

Health inequities as observed in pediatric rheumatic diseases are likely to emerge from a complex interplay between social and biological factors. The important contribution of historical and repetitive trauma deserves further exploration.

Ethnicity, disease severity, and survival in Canadian patients with primary biliary cholangitis

BACKGROUND AND AIMS

We investigated associations between ethnicity, survival, and disease severity in a diverse Canadian cohort of patients with primary biliary cholangitis (PBC).

APPROACH AND RESULTS

Patients with PBC were included from the Canadian Network for Autoimmune Liver Disease. Ethnicity was defined using a modified list adopted from Statistics Canada, and ethnicities with small samples were grouped. Clinical events were defined as liver decompensation, HCC, liver transplantation, or death. Clinical event-free and liver transplantation-free survival were analyzed using Cox regression. Trajectories of serum liver function tests were assessed over time using mixed-effects regression. Health-related quality of life was assessed using the Short Form 36, the PBC-40 questionnaire, and the 5-D Itch scale and analyzed using mixed-effects regression. The cohort included 1538 patients with PBC from six sites and was comprised of 82% White, 4.7% Indigenous, 5.5% East Asian, 2.6% South Asian, and 5.1% miscellaneous ethnicities. Indigenous patients were the only ethnic group with impaired liver transplant-free and event-free survival compared to White patients (HR, 3.66; 95% CI, 2.23-6.01; HR, 3.09; 95% CI, 1.94-4.92). Indigenous patients were more likely to have a clinical event before diagnosis (10%) than all other ethnic groups despite similar age at diagnosis. Indigenous patients presented with higher alkaline phosphatase, total bilirubin, and GLOBE scores than White patients; and these relative elevations persisted during follow-up.

CONCLUSIONS

Indigenous Canadians with PBC present with advanced disease and have worse long-term outcomes compared to White patients.

Epidemiology of rheumatoid arthritis: genetic and environmental influences

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic systemic disease characterized by articular involvement and extra-articular manifestations. The incidence and prevalence of the disease vary across populations, and there is an ongoing debate on whether a change of RA occurrence over time exists or is due to methodological issues and other biases. Moreover, the disease's onset is related to an interaction of genetic and environmental factors that influence its expression.

AREAS COVERED

This review explores the latest knowledge on RA epidemiology and the possible risk factors associated with its presentation to identify potential warning signs that may in the future help disease management.

EXPERT OPINION

Current epidemiological evidence suggests a significant impact of smoking, sex hormones, and lifestyle status in RA occurrence. However, the association between these variables has not yet been thoroughly studied. Still, their effect must be interpreted as they may present subsequently integral indicators for a more rational approach of the disease.

Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation

In this review, we explore systemization of knowledge about the triggering effects of non-genetic factors in pathogenic mechanisms that contribute to the development of rheumatoid arthritis (RA). Possible mechanisms involving environmental and individual factors in RA pathogenesis were analyzed, namely, infections, mental stress, sleep deprivation ecology, age, perinatal and gender factors, eating habits, obesity and smoking. The non-genetic factors modulate basic processes in the body with the impact of these factors being non-specific, but these common challenges may be decisive for advancement of the disease in the predisposed body at risk for RA. The provocation of this particular disease is associated with the presence of congenital loci minoris resistentia. The more frequent non-genetic factors form tangles of interdependent relationships and, thereby, several interdependent external factors hit one vulnerable basic process at once, either provoking or reinforcing each other. Understanding the specific mechanisms by which environmental and individual factors impact an individual under RA risk in the preclinical stages can contribute to early disease diagnosis and, if the factor is modifiable, might be useful for the prevention or delay of its development.

Sleep Problems Mediate the Relationship Between Psychosocial Stress and Pain Facilitation in Native Americans: A Structural Equation Modeling Analysis from the Oklahoma Study of Native American Pain Risk

BACKGROUND

Native Americans (NAs) are more likely to experience chronic pain than non-Hispanic Whites (NHWs); however, the proximate causes predisposing NAs to chronic pain remain elusive. Likely due to centuries of adversity, discrimination, and marginalization, NAs report greater psychological stress than NHWs, which may place them at risk for sleep problems, a well-established risk factor for chronic pain onset.

PURPOSE

This study examined the effects of psychological stress and sleep problems on subjective and physiological measures of pain processing in NAs and NHWs.

METHODS

Structural equation modeling was used to determine whether ethnicity (NA or NHW) was associated with psychological stress or sleep problems and whether these variables were related to conditioned pain modulation of pain perception (CPM-pain) and the nociceptive flexion reflex (CPM-NFR), temporal summation of pain (TS-pain) and NFR (TS-NFR), and pain tolerance in a sample of 302 (153 NAs) pain-free participants.

RESULTS

NAs experienced more psychological stress (Estimate = 0.027, p = .009) and sleep problems (Estimate = 1.375, p = .015) than NHWs. When controlling for age, sex, physical activity, BMI, and general health, NA ethnicity was no longer related to greater sleep problems. Psychological stress was also related to sleep problems (Estimate = 30.173, p = <.001) and psychological stress promoted sleep problems in NAs (indirect effect = 0.802, p = .014). In turn, sleep problems were associated with greater TS-pain (Estimate = 0.714, p = .004), but not other pain measures.

CONCLUSIONS

Sleep problems may contribute to chronic pain risk by facilitating pain perception without affecting facilitation of spinal neurons or endogenous inhibition of nociceptive processes. Since psychological stress promoted pain facilitation via enhanced sleep problems, efforts to reduce psychological stress and sleep problems among NAs may improve health outcomes.

The Unmet Need for Orthopaedic Services Among American Indian and Alaska Native Communities in the United States

ABSTRACT

Historic and present-day marginalization has resulted in a high burden of disease and worse health outcomes for American Indian and Alaska Native (AI/AN) communities in the United States. Musculoskeletal disease is the leading cause of disability for the general population in the U.S. today. However, few have examined musculoskeletal disease burden and access to orthopaedic surgical care in the AI/AN communities. A high prevalence of hip dysplasia, arthritis, back pain, and diabetes, and a high incidence of trauma and road traffic-related mortality, suggest a disproportionately high burden of musculoskeletal pathology among the AI/AN communities and a substantial need for orthopaedic surgical services. Unfortunately, AI/AN patients face many barriers to receiving specialty care, including long travel distances and limited transportation to health facilities, inadequate staff and resources at Indian Health Service (IHS)-funded facilities, insufficient funding for referral to specialists outside of the IHS network, and sociocultural barriers that complicate health-system navigation and erode trust between patients and providers. For those who manage to access orthopaedic surgery, AI/AN patients face worse outcomes and more complications than White patients. There is an urgent need for orthopaedic surgeons to participate in improving the availability of quality orthopaedic services for AI/AN patients through training and support of local providers, volunteerism, advocating for a greater investment in the IHS Purchased/Referred Care program, expanding telemedicine capabilities, and supporting community-based participatory research activities.

The Relationship Between Experienced Discrimination and Pronociceptive Processes in Native Americans: Results From the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) have higher pain rates than the general U.S. population. It has been found that increased central sensitization and reduced pain inhibition are pronociceptive processes that increase pain risk; yet, little attention has focused on the influence of psychosocial factors. Discrimination is a psychosocial factor associated with increased pain in other minoritized groups; however, it is unclear whether it also promotes pain in NAs. This study analyzed data from 269 healthy, pain-free participants (N = 134 non-Hispanic whites [NHWs], N = 135 NAs) from the Oklahoma Study of Native American Pain Risk. Experienced discrimination was measured using the Everyday Discrimination Scale (EDS). Nociceptive processes were measured via static measures of spinal sensitivity (nociceptive flexion reflex [NFR] threshold, 3-stimulation NFR threshold), temporal summation of pain (TS-Pain) and nociceptive flexion reflex (TS-NFR), and conditioned pain modulation of pain (CPM-Pain) and NFR (CPM-NFR). Results demonstrated that greater discrimination was associated with enhanced TS-NFR and impaired CPM-NFR but not static measures of spinal sensitivity or measures of pain modulation (TS-Pain, CPM-Pain). Although the effects of discrimination on outcomes were similar in both groups (not moderated by ethnicity), NAs experienced higher levels of discrimination and therefore discrimination mediated a relationship between ethnicity and impaired CPM-NFR. This indicates experienced discrimination may promote a pain risk phenotype in NAs that involves spinal sensitization resulting from impaired inhibition of spinal nociception without sensitization of pain experience. PERSPECTIVE: This study found that discrimination was associated with spinal sensitization and impaired descending inhibition of spinal nociception. These findings bolster our understanding of how social stressors experienced disproportionately by minoritized groups can contribute to pain outcomes.

Psychosocial and cardiometabolic predictors of chronic pain onset in Native Americans: serial mediation analyses of 2-year prospective data from the Oklahoma Study of Native American Pain Risk

ABSTRACT

Chronic pain results in considerable suffering, as well as significant economic and societal costs. Previous evidence suggests that Native Americans (NAs) have higher rates of chronic pain than other U.S. racial or ethnic groups, but the mechanisms contributing to this pain disparity are poorly understood. The Oklahoma Study of Native American Pain Risk was developed to address this issue and recruited healthy, pain-free NAs and non-Hispanic Whites. Cross-sectional analyses identified several measures of adversity (eg, trauma and discrimination), cognitive-affective factors (perceived stress and pain-related anxiety/catastrophizing), and cardiometabolic factors (eg, body mass index, blood pressure, and heart rate variability) that were associated with pronociceptive processes (eg, central sensitization, descending inhibition, and hyperalgesia). Every 6-months after enrollment, eligible participants (N = 277) were recontacted and assessed for the onset of chronic pain. This study examines predictors of chronic pain onset in the 222 participants (80%) who responded over the first 2 years. The results show that NAs developed chronic pain at a higher rate than non-Hispanic Whites (OR = 2.902, P < 0.05), even after controlling for age, sex, income, and education. Moreover, serial mediation models identified several potential pathways to chronic pain onset within the NA group. These paths included perceived discrimination, psychological stress, pain-related anxiety, a composite measure of cardiometabolic risk, and impaired descending inhibition of spinal nociception (assessed from conditioned pain modulation of the nociceptive flexion reflex). These results provide the first prospective evidence for a pain disparity in NAs that seems to be promoted by psychosocial, cardiometabolic, and pronociceptive mechanisms.

Hospitalizations Associated With Rheumatic Disease in Alaska, 2015-2018

Objective

Few studies have evaluated hospitalizations associated with rheumatic disease in Indigenous North American populations. The objective of this study was to determine the characteristics of people hospitalized with rheumatic disease in Alaska, including a comparison of hospitalizations for Alaska Native/American Indian (AN/AI) people in Alaska compared with those of other races.

Methods

We used statewide hospital discharge data from the Alaska Health Facilities Data Reporting Program from 2015 to 2018 for this study. Cases were ascertained based on discharge diagnosis (any listed) of a defined set of rheumatic diseases. We determined characteristics associated with rheumatic disease hospitalizations, including age, gender, and race. Using multivariate modeling, we determined risk factors for hospitalization overall, as well as for specific rheumatic diseases. We compared characteristics of hospital encounters for people with or without rheumatic diseases and by race.

Results

We identified 15975 people ever hospitalized with rheumatic disease in the study period and 87138 controls hospitalized but without any rheumatic disease diagnosis. Cases were older than controls and more likely to be female. The three most common types of rheumatic disease associated with hospitalization were osteoarthritis, gout, and rheumatoid arthritis. Compared with other races, AN/AI people were more likely to be hospitalized with rheumatic disease, and this association was true for all specific diseases other than gout.

Conclusion

Hospitalizations associated with rheumatic disease are common in Alaska, with an increased likelihood of hospitalization for AN/AI people. This adds to the literature on health disparities in Indigenous North American populations.

Pre-RA: Can early diagnosis lead to prevention?

Rheumatoid arthritis (RA) is currently diagnosed and treated once an individual displays the clinical findings of inflammatory arthritis (IA). However, growing evidence supports that there is a 'pre-RA' stage that can be identified through factors such as autoantibodies in absence of clinically apparent IA. In particular, biomarkers, including antibodies to citrullinated protein antigens (ACPA), demonstrate a high risk for future IA/RA, and multiple clinical trials have been developed to intervene in individuals in pre-RA to prevent or delay clinically apparent disease. Herein, we will discuss in more depth what is currently known about the natural history of RA, and the emerging possibility that early 'diagnosis' of RA-related autoimmunity followed by an intervention can lead to the delay or prevention of the first onset of clinically apparent RA.

Modulatory role of prenatal alcohol exposure and adolescent stress on the response to arthritis challenge in adult female rats

Background

There are known environmental risk factors associated with rheumatoid arthritis; however, less is known regarding how the prenatal environment impacts later-life risk for rheumatoid arthritis. Based on preliminary clinical data suggesting that individuals with fetal alcohol spectrum disorder (FASD) are at higher risk for autoimmune disorders, this study investigated the modulatory impact of prenatal alcohol exposure (PAE) on the inflammatory disease profile in an adjuvant-induced arthritis rat model.

Methods

Pregnant rats received liquid ethanol or control diet throughout gestation. To model the increased exposure to stressors often experienced by individuals with FASD, adolescent offspring were exposed to chronic mild stress (CMS) or remained undisturbed. In adulthood, experimental arthritis was initiated and rats terminated either at the peak or following resolution from inflammation to assess endocrine, immune, and histopathological outcomes.

Findings

PAE rats had an increased incidence and severity of, and impaired recovery from, arthritis. Increased joint damage was observed in PAE animals, even in the face of apparent recovery from the clinical signs of arthritis, while it appeared that oestradiol may have a protective role. Moreover, with the combination of PAE and adolescent stress, increased macrophage density was detected in the synovium of PAE but not control rats.

Interpretation

These findings demonstrate that PAE alters the severity and course of arthritis, highlighting the potential immunomodulatory impact of adverse prenatal exposures. In particular, these data have implications for understanding preliminary data that suggest a heightened propensity for autoimmune disorders in individuals with FASD.

The Association Between Adverse Life Events, Psychological Stress, and Pain-Promoting Affect and Cognitions in Native Americans: Results from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) experience higher rates of chronic pain. To examine the mechanisms for this pain inequity, we have previously shown that NAs report higher levels of pain-related anxiety and pain catastrophizing, which are in turn related to pronociceptive (pain-promoting) processes. But, it is currently unclear why NAs would report greater pain-related anxiety and catastrophizing. Given that NAs are also more likely to experience adverse life events (ALEs) and associated psychological distress, it was hypothesized that higher anxiety/catastrophizing in NAs would be partially explained by higher rates of ALEs and psychological distress. Structural equation modeling was used to analyze these pathways (NA ethnicity ➔ ALEs ➔ psychological distress ➔ pain anxiety/catastrophizing) in 305 healthy, pain-free adults (N = 155 NAs, N = 150 non-Hispanic Whites [NHWs]). Pain-related anxiety and situational pain catastrophizing were assessed in response to a variety of painful tasks. The Life Events Checklist was used to assess cumulative exposure to ALEs that directly happened to each participant. A latent psychological distress variable was modeled from self-reported perceived stress and psychological symptoms. Results found that NAs experienced more ALEs and greater psychological distress which was associated with higher rates of pain-related anxiety and pain catastrophizing. Notably, NAs did not report greater psychological distress when controlling for ALE exposure. This suggests that a higher risk of chronic pain in NAs may be due, in part, to psychological distress, pain-related anxiety, and pain catastrophizing that are promoted by exposure to ALEs. These results highlight several targets for intervention to decrease NA pain risk.

«Living with rheumatoid arthritis» in an indigenous qom population in Argentina. A qualitative study

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic disease which impacts patients' quality of life. The prevalence of RA in the qom population was 2.4% and represented an aggressive and disabling disease. The study goal was to describe the experience of the indigenous qom community individual suffering from RA, along with their experience with the local health care system in the city of Rosario, Santa Fe, Argentina.

METHODS

Qualitative Study using techniques of participant observation and semi-structured interviews; following a guideline developed by a multidisciplinary research group comprising anthropologists, rheumatologists, nurses, and psychologists. A triangulation strategy was implemented for the analysis.

RESULTS

A total of 33 interviews were conducted in 29 individuals with RA. The results showed a "normalization" of their symptoms and of their limitations in performing daily tasks. The individuals' relationship with the local health care system was complex and limited in several aspects (e.g. access to health care, continuity of treatment, complexity of medical care pathway and lack of cultural competence).

CONCLUSIONS

RA is a disease that has a negative impact on the daily lives of the qom people living in Rosario. Improving the relationship between this population and the local health care system as well as the implementation of multidisciplinary work should be priorities.

Are Cardiometabolic Markers of Allostatic Load Associated With Pronociceptive Processes in Native Americans?: A Structural Equation Modeling Analysis From the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) experience higher rates of chronic pain than the general U.S. population, but the risk factors for this pain disparity are unknown. NAs also experience high rates of stressors and cardiovascular and metabolic health disparities (eg, diabetes, cardiovascular disease) consistent with allostatic load (stress-related wear-and-tear on homeostatic systems). Given that allostatic load is associated with chronic pain, then allostatic load may contribute to their pain disparity. Data from 302 healthy, pain-free men and women (153 NAs, 149 non-Hispanic Whites [NHW]) were analyzed using structural equation modeling to determine whether cardiometabolic allostatic load (body mass index, blood pressure, heart rate variability) mediated the relationship between NA ethnicity and experimental measures of pronociceptive processes: temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR), conditioned pain modulation of pain (CPM-pain) and NFR (CPM-NFR), and pain tolerance. Results indicated that NAs experienced greater cardiometabolic allostatic load that was related to enhanced TS-NFR and impaired CPM-NFR. Cardiometabolic allostatic load was unrelated to measures of pain perception (CPM-pain, TS-pain, pain sensitivity). This suggests cardiometabolic allostatic load may promote spinal sensitization in healthy NAs, that is not concomitant with pain sensitization, perhaps representing a unique pain risk phenotype in NAs. PERSPECTIVE: Healthy, pain-free Native Americans experienced greater cardiometabolic allostatic load that was associated with a pronociceptive pain phenotype indicative of latent spinal sensitization (ie, spinal sensitization not associated with hyperalgesia). This latent spinal sensitization could represent a pain risk phenotype for this population.

The Therapeutic Landscape of Rheumatoid Arthritis: Current State and Future Directions

Rheumatoid arthritis (RA) is a debilitating autoimmune disease with grave physical, emotional and socioeconomic consequences. Despite advances in targeted biologic and pharmacologic interventions that have recently come to market, many patients with RA continue to have inadequate response to therapies, or intolerable side effects, with resultant progression of their disease. In this review, we detail multiple biomolecular pathways involved in RA disease pathogenesis to elucidate and highlight pathways that have been therapeutic targets in managing this systemic autoimmune disease. Here we present an up-to-date accounting of both emerging and approved pharmacological treatments for RA, detailing their discovery, mechanisms of action, efficacy, and limitations. Finally, we turn to the emerging fields of bioengineering and cell therapy to illuminate possible future targeted therapeutic options that combine material and biological sciences for localized therapeutic action with the potential to greatly reduce side effects seen in systemically applied treatment modalities.

Sexual Dimorphism in the Expression of Pain Phenotype in Preclinical Models of Rheumatoid Arthritis

Rheumatoid arthritis is one of most frequent rheumatic diseases, affecting around 1% of the population worldwide. Pain impacting the quality of life for the patient with rheumatoid arthritis, is often the primary factor leading them to seek medical care. Although sex-related differences in humans and animal models of rheumatoid arthritis are described, the correlation between pain and sex in rheumatoid arthritis has only recently been directly examined. Here we review the literature and explore the mechanisms underlying the expression of the pain phenotype in females and males in preclinical models of rheumatoid arthritis.

Rheumatoid Arthritis Pathogenesis, Prediction, and Prevention: An Emerging Paradigm Shift

Rheumatoid arthritis (RA) is currently diagnosed and treated when an individual presents with signs and symptoms of inflammatory arthritis (IA) as well as other features, such as autoantibodies and/or imaging findings, that provide sufficient confidence that the individual has RA-like IA (e.g., meeting established classification criteria) that warrants therapeutic intervention. However, it is now known that there is a stage of seropositive RA during which circulating biomarkers and other factors (e.g., joint symptoms) can be used to predict if and when an individual who does not currently have IA may develop future clinically apparent IA and classifiable RA. Indeed, the discovery of the "pre-RA" stage of seropositive disease has led to the development of several clinical trials in which individuals are studied to identify ways to delay or prevent the onset of clinically apparent IA/RA. This review focuses on several issues pertinent to understanding the prevention of RA. These include discussion of the pathogenesis of pre-RA development, prediction of the likelihood and timing of future classifiable RA, and a review of completed and ongoing clinical trials in RA prevention. Furthermore, this review discusses challenges and opportunities to be addressed to effect a paradigm shift in RA, where in the near future, proactive risk assessment focused on prevention of RA will become a public health strategy in much the same manner as cardiovascular disease is managed today.

The role of posttranslational modifications in generating neo-epitopes that bind to rheumatoid arthritis-associated HLA-DR alleles and promote autoimmune T cell responses

While antibodies to citrullinated proteins have become a diagnostic hallmark in rheumatoid arthritis (RA), we still do not understand how the autoimmune T cell response is influenced by these citrullinated proteins. To investigate the role of citrullinated antigens in HLA-DR1- and DR4-restricted T cell responses, we utilized mouse models that express these MHC-II alleles to determine the relationship between citrullinated peptide affinity for these DR molecules and the ability of these peptides to induce a T cell response. Using a set of peptides from proteins thought to be targeted by the autoimmune T cell responses in RA, aggrecan, vimentin, fibrinogen, and type II collagen, we found that while citrullination can enhance the binding affinity for these DR alleles, it does not always do so, even when in the critical P4 position. Moreover, if peptide citrullination does enhance HLA-DR binding affinity, it does not necessarily predict the generation of a T cell response. Conversely, citrullinated peptides can stimulate T cells without changing the peptide binding affinity for HLA-DR1 or DR4. Furthermore, citrullination of an autoantigen, type II collagen, which enhances binding affinity to HLA-DR1 did not enhance the severity of autoimmune arthritis in HLA-DR1 transgenic mice. Additional analysis of clonal T cell populations stimulated by these peptides indicated cross recognition of citrullinated and wild type peptides can occur in some instances, while in others cases the citrullination generates a novel T cell epitope. Finally, cytokine profiles of the wild type and citrullinated peptide stimulated T cells unveiled a significant disconnect between proliferation and cytokine production. Altogether, these data demonstrate the lack of support for a simplified model with universal correlation between affinity for HLA-DR alleles, immunogenicity and arthritogenicity of citrullinated peptides. Additionally they highlight the complexity of both T cell receptor recognition of citrulline as well as its potential conformational effects on the peptide:HLA-DR complex as recognized by a self-reactive cell receptor.

Access to healthcare system of indigenous communities with musculoskeletal disorders and rheumatic disease in Chaco, Argentina: a qualitative study

Introduction/objectives

The objective of this study is to describe the local healthcare system from the perspective of the health professionals, community health workers, and local representatives of the qom community living in the province of Chaco, Argentina.

Methods

A qualitative study, with an ethnographic approach, was carried out using two techniques: non-participant observations and semi-structured interviews. A guide for the interviews was designed and developed by a multidisciplinary group of GLADERPO researchers. The main aspects included were the following: reference into the local healthcare system and accessibility to the system. Andersen’s base conceptual model of health service utilization was applied for the analysis and for structuring the results.

Results

A total of 21 people were interviewed, twelve women and nine men with an age ranging between 25 and 60 years old. The main findings were different barriers (communication and cultural) between the community and the healthcare system; “navigation” within the health system carried out by the qom community; and migration and bureaucratization of the health system.

Conclusions

These findings should be incorporated into educational strategies to improve access to healthcare system and adherence to medical treatment, establishing an interaction between the different levels of the local care system and providing community health workers with an appropriate training with the support of the community representatives.

Key Points • The different barriers between the community and the healthcare system were described. • The “navigation” within the health system carried out by the qom community and the migration were relevant points. • The bureaucratization of the health system and the need to design and implement educational strategies in the future were highlighted.

Understanding the Disproportionate Burden of Rheumatic Diseases in Indigenous North American Populations

Studies have described a high incidence and prevalence of several rheumatic diseases in indigenous North American populations. Conditions studied most frequently with consistently high burden of disease include rheumatoid arthritis, spondyloarthritis, and systemic lupus erythematosus. Crystal-induced arthritis has been reported to have a lower prevalence than expected. Information about genetic and environmental risk factors is available for some of these conditions. An awareness of the epidemiology of rheumatic diseases in indigenous North American populations is important for clinicians involved in caring for patients in these populations as well as for planning health service delivery in these communities.

Prevalence of Juvenile Idiopathic Arthritis in the Alaska Native Population

OBJECTIVE

To determine the prevalence and clinical characteristics of juvenile idiopathic arthritis (JIA) in Alaska Native children.

METHODS

Potential cases of JIA were identified by querying administrative data from hospitals and clinics in the Alaska Tribal Health System for codes possibly identifying JIA. Medical record abstraction was performed to confirm criteria met for JIA, demographic and clinical characteristics, and treatment patterns. Individuals age ≤18 years with a confirmed diagnosis of JIA were included. The denominator for prevalence was the 2015 Alaska Area Indian Health Service user population age of ≤18 years.

RESULTS

The unadjusted prevalence of JIA in Alaska Native children was 74.6 per 100,000 (age-adjusted 79.0 per 100,000). JIA was more common in females than males (unadjusted prevalence 105.8 versus 45.0 per 100,000). Oligoarthritis was the most common subtype (31% of cases), but polyarthritis and enthesitis-related arthritis were also common (26% and 24% of cases, respectively), with a notably high prevalence of enthesitis-related arthritis. The median age at diagnosis was 9 years. Of the combined cohort with results available, 56% were antinuclear antibody positive, 23% were rheumatoid factor positive, 19% were anti-cyclic citrullinated peptide antibody positive, and 57% had the presence of HLA-B27. Uveitis had been diagnosed in 16% of cases.

CONCLUSION

The prevalence of JIA in Alaska Native children may be higher than the general US population. Enthesitis-related arthritis makes up a higher proportion of cases than in other populations described likely because of the high prevalence of HLA-B27 in this population.

Leflunomide monotherapy versus combination therapy with conventional synthetic disease-modifying antirheumatic drugs for rheumatoid arthritis: a retrospective study

Leflunomide (LEF) is a conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) for the treatment of rheumatoid arthritis. However, there are few reports on the comparison of efficacy between LEF alone and combined with other csDMARDs. Here, the efficacy and safety of LEF monotherapy (88) and combination (361) therapy groups were evaluated. After 3 months, there were no significant differences in 28-joint disease activity score (DAS28), health assessment questionnaire (HAQ), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) between the monotherapy and combination groups (all P > 0.05). According to the European League Against Rheumatism (EULAR) response criteria, it was found that the DAS28 response rates were similar in the two groups (P > 0.05). Besides, the two groups presented similar safety profiles. Subgroup analysis found that there was no difference in efficacy among the three combined therapies (LEF + methotrexate (MTX), LEF + hydroxychloroquine (HCQ), and LEF + MTX + HCQ) and LEF monotherapy. Furthermore, when the dose of LEF was less than 40 mg/day, no significant difference in efficacy was observed between low and high doses. Overall, these results indicated that low dose LEF monotherapy was not inferior to the combination therapy.

«Living with Rheumatoid Arthritis» in an Indigenous Qom Population in Argentina. A Qualitative Study

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic disease which impacts patients' quality of life. The prevalence of RA in the qom population was 2.4% and represented an aggressive and disabling disease. The study goal was to describe the experience of the indigenous qom community individual suffering from RA, along with their experience with the local health care system in the city of Rosario, Santa Fe, Argentina.

METHODS

Qualitative Study using techniques of participant observation and semi-structured interviews; following a guideline developed by a multidisciplinary research group comprising anthropologists, rheumatologists, nurses, and psychologists. A triangulation strategy was implemented for the analysis.

RESULTS

A total of 33 interviews were conducted in 29 individuals with RA. The results showed a «normalization» of their symptoms and of their limitations in performing daily tasks. The individual relationships with the local health care system was complex and limited in several aspects (e.g. access to health care, continuity of treatment, complexity of medical care pathway and lack of cultural competence).

CONCLUSIONS

RA is a disease that has a negative impact on the daily lives of the qom people living in Rosario. Improving the relationship between this population and the local health care system as well as the implementation of multidisciplinary work should be priorities.

Prevalence of musculoskeletal disorders and rheumatic diseases in an Argentinean indigenous Wichi community

OBJECTIVE

To estimate the prevalence of musculoskeletal disorders (MSK) and rheumatic diseases in an indigenous Wichi population in Argentina.

METHODS

This is a cross-sectional, community-based study using the Community-Oriented Program for the Control of Rheumatic Diseases (COPCORD) methodology in ≥ 18-year-old subjects. Validated surveys were conducted by trained interviewers. Subjects with MSK pain (positive cases) were evaluated by internists and rheumatologists for diagnosis and treatment.

RESULTS

A total of 648 interviews were performed (90.4% of the census population). Mean age was 37.5 years (SD 14.8), and 379 (58.5%) were female. The mean years of education was 7.0 (SD 3.7); 552 subjects (85.2%) were covered by the public health care system. A total of 216 (33.3%) subjects had MSK pain in the last 7 days. Rheumatic disease prevalence was as follows: mechanical back pain (19.0%), rheumatic regional pain syndrome (5.2%), osteoarthritis (3.2%), rheumatoid arthritis (RA) (3.2%), inflammatory back pain (1.2%), undifferentiated arthritis (0.3%), Sjögren syndrome (0.15%), and fibromyalgia (0.15%). RA patients included 19 (90.5%) women and 9 (42.9%) with RA family history. One hundred percent were seropositive and 66.7% showed radiologic erosions. The mean of Disease Activity Score [DAS-28 (ESR)] at the time of diagnosis was 5.1 (SD 1.5) and the Health Assessment Questionnaire Disability Index (HAQ-DI) was 0.8 (SD 0.4).

CONCLUSION

RA prevalence was 3.2%, one of the highest reported using the COPCORD methodology in indigenous and non-indigenous peoples in Latin America, with a high percentage of family cases. Pain and functional capacity were the variables allowing patients' early referral to a specialist. Key Points • The RA prevalence was 3.2%, one of the highest reported using COPCORD methodology in indigenous and non-indigenous peoples in Latin America. • The patients with RA had high percentage of familiar history of RA. • The pain and functional capacity were the variables associated with a diagnosis of any rheumatic disease and should be considered for early referral. • The mean of the delay in the diagnosis was 5.8 years. In this community, the lack of the "migration health" phenomenon may be a social determinant that negatively impacts their health.

Current Understanding of an Emerging Role of HLA-DRB1 Gene in Rheumatoid Arthritis-From Research to Clinical Practice

Rheumatoid arthritis (RA) is an autoimmune disease with an unclear pathogenic mechanism. However, it has been proven that the key underlying risk factor is a genetic predisposition. Association studies of the HLA-DRB1 gene clearly indicate its importance in RA morbidity. This review presents the current state of knowledge on the impact of HLA-DRB1 gene, functioning both as a component of the patient’s genome and as an environmental risk factor. The impact of known HLA-DRB1 risk variants on the specific structure of the polymorphic HLA-DR molecule, and epitope binding affinity, is presented. The issues of the potential influence of HLA-DRB1 on the occurrence of non-articular disease manifestations and response to treatment are also discussed. A deeper understanding of the role of the HLA-DRB1 gene is essential to explore the complex nature of RA, which is a result of multiple contributing factors, including genetic, epigenetic and environmental factors. It also creates new opportunities to develop modern and personalized forms of therapy.

Chikungunya Virus Infection Outcome: A Systematic Review of Host Genetics

Background: Chikungunya virus (CHIKV) is a global concern, inducing chikungunya fever and trigging an arthritogenic chronic phase beyond some severe forms. Outcomes of CHIKV infections in humans are dependent on genetic variations. Here, a systematic review was performed to show evidence of genetic variations on infection outcomes of patients. Methods: Searches were performed in Scopus, SciELO, MEDLINE/PubMed, Web of Science, OneFile (GALE), Periódicos CAPES and ScienceDirect Journals databases. The PICOS approach was used to assess the eligibility of records. A meta-analysis was also conducted to show an association between described alleles/genes and CHIKV infection outcome. Results: Reviews of genetic variants were conducted on genes: CD 209, OAS1, OAS2, OAS3, MIF, TLR-3, TLR-7, TLR-8, MYD-88, KIR, HLA-B; HLA-C; DRB1 and DQB1. Studies were performed on Gabon, Singapore, and India, including Indians, Malay, Gabonese and Chinese ethnicities and published between 2009-2017. The meta-analysis was performed with DRB1 *01; *03; *04; *07; *10; *11; *13; *14 and *15 and DQB1 *02; *03; *05 and *06 alleles with Indian population sample. Sampling power was >80% and a significant positive association between DRB1*14 and CHIKV infection was found (OR = 1.67, 95% CI = 1.04-2.67; p = .03). Conclusion: Majority of the studies were conducted in India. Meta-analysis suggests that DRB1*14 is related to the susceptibility of symptomatic CHIKV infection in Indian population. The literature about CHIKV infection and genetic variations is scarce. The precise role of genetic variation in CHIKV is not clear yet. Further studies are necessary to provide more concrete evidences.

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

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

Cohort profile of a US military population for evaluating pre-disease and disease serological biomarkers in rheumatoid and reactive arthritis: Rationale, organization, design, and baseline characteristics

Purpose

The etiology of several autoimmune disorders, including rheumatoid arthritis, remains unknown. While there are clear phases of disease progression, the mechanisms of transition between these phases are poorly understood. Additionally, treatment focuses on an alteration of the biological processes to prevent joint damage and functional decline. A goal is to potentially treat the disease during the preclinical phase to mitigate the disease process. Reactive arthritis is another rheumatologic condition known to be secondary to a distal infection. While prevention of infection would mitigate risk, serologic profiling patients with the disease may assist in the elucidation of potential disease risk factors. This study was initiated to enable an assessment of pre-disease biomarkers in patients newly diagnosed with rheumatoid arthritis and reactive arthritis.

Participants

A retrospective cohort of 500 rheumatoid and 500 reactive arthritis cases with 500 matched controls was drawn from a population of active component US military personnel. Appropriate inclusion criteria limited subject selection. Additionally, 4 serum samples (3 pre-disease and 1 disease-associated) were obtained for each case and control.

Findings to date

The established cohort provides the framework for novel exploration of the host response through serum profiling and seroepidemiology prior to disease onset.

Future plans

This study establishes the framework for the evaluation of novel serum biomarkers enabling the identification of signals prior to clinical disease that may enable disease prediction, elucidate disease pathogenesis and identify novel exposures leading to increased disease risk and/or disease severity.

AA, Lukashev AN. Emerging Concepts and Challenges in Rheumatoid Arthritis Gene Therapy

Rheumatoid arthritis (RA) is a systemic inflammatory joint disease affecting about 1% of the population worldwide. Current treatment approaches do not ensure a cure for every patient. Moreover, classical regimens are based on nontargeted systemic immune suppression and have significant side effects. Biological treatment has advanced considerably but efficacy and specificity issues remain. Gene therapy is one of the potential future directions for RA therapy, which is rapidly developing. Several gene therapy trials done so far have been of moderate success, but experimental and genetics studies have yielded novel targets. As a result, the arsenal of gene therapy tools keeps growing. Currently, both viral and nonviral delivery systems are used for RA therapy. Herein, we review recent approaches for RA gene therapy.

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

INTRODUCTION

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Epigenetic Changes in the Pathogenesis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease that affects about 1% of the world’s population. The etiology of RA remains unknown. It is considered to occur in the presence of genetic and environmental factors. An increasing body of evidence pinpoints that epigenetic modifications play an important role in the regulation of RA pathogenesis. Epigenetics causes heritable phenotype changes that are not determined by changes in the DNA sequence. The major epigenetic mechanisms include DNA methylation, histone proteins modifications and changes in gene expression caused by microRNAs and other non-coding RNAs. These modifications are reversible and could be modulated by diet, drugs, and other environmental factors. Specific changes in DNA methylation, histone modifications and abnormal expression of non-coding RNAs associated with RA have already been identified. This review focuses on the role of these multiple epigenetic factors in the pathogenesis and progression of the disease, not only in synovial fibroblasts, immune cells, but also in the peripheral blood of patients with RA, which clearly shows their high diagnostic potential and promising targets for therapy in the future.

Review of chronic non-cancer pain research among Aboriginal people in Canada

Purpose

Aboriginal people in Canada are disproportionately affected by chronic illnesses, compared to non-Aboriginal Canadians. The purpose of this review was to determine whether differences exist between the two groups with respect to chronic non-cancer pain (CNCP) in order to better inform clinical practice and to identify research gaps.

Data sources

Four electronic databases were searched for the period of 1990-2015.

Study selection

Only English and French language original studies that examined CNCP prevalence, assessment tools and beliefs among Aboriginal people in Canada were considered.

Data extraction

Data extracted included Aboriginal group, geographic location, study setting and pain definition (for prevalence studies only).

Results of data synthesis

A total of 11 studies matched the selection criteria: 10 reported estimates of chronic pain prevalence among Aboriginal people in Canada, 1 was about a culturally adapted pain assessment tool, and no study was found about CNCP beliefs within Aboriginal people.

Conclusion

CNCP among Aboriginal people is still a largely unexplored research field. The limited evidence available so far does not allow us to conclude that CNCP affects a higher proportion of Aboriginal than non-Aboriginal people in Canada. However, arthritis, a specific condition associated with chronic pain, is more prevalent in Aboriginal than non-Aboriginal people. Additional research is needed on other CNCP types and conditions. Furthermore, pain assessment tools are not culturally adapted and clinicians should inquire more about the beliefs of Aboriginal patients to make them feel safer and to better target interventions.

Human Leukocyte Antigen-Disease Associations in Rheumatoid Arthritis

The cause and pathogenesis of rheumatoid arthritis (RA) are influenced by environmental and genetic risk factors. Shared epitope-coding human leukocyte antigen (HLA)-DRB1 alleles increase RA risk and severity; however, the underlying mechanisms of action remain unclear. In contrast, several other DRB1 alleles protect against RA. Additionally, genome-wide association studies suggest that RA associates with other, HLA and non-HLA, genes; but the relative contributions of such risk loci to RA are incompletely understood. Future research challenges include integrating the epidemiologic and genomic data into validated arthritogenic pathways and determining the mechanisms of interaction between RA risk genes and environmental influences.

Systematic review of rheumatic disease phenotypes and outcomes in the Indigenous populations of Canada, the USA, Australia and New Zealand

We performed a systematic review designed to characterize clinical phenotypes and outcomes in Indigenous populations with rheumatic disease to enhance the understanding of how rheumatic disease presents in Indigenous populations and allow for better projection of the healthcare needs of the communities affected. A systematic search was performed in medical (Medline, EMBASE, CINAHL), Indigenous and conference abstract databases (to June 2015). Search terms for Indigenous populations were combined with terms for inflammatory arthritis conditions, connective tissue disorders, crystal arthritis and osteoarthritis. Studies were included if they reported on disease features, disease activity measures, or patient-reported outcomes in Canadian, American, Australian or New Zealand Indigenous populations. Data were extracted in duplicate, and a narrative summary was prepared. A total of 5269 titles and abstracts were reviewed, of which 504 underwent full-text review and 85 met inclusion criteria. Nearly all the studies described outcomes in the North American populations (n = 77), with only four studies from Australia and four studies from New Zealand. The majority of studies were in rheumatoid arthritis (n = 31) and systemic lupus erythematosus (n = 19). Indigenous patients with rheumatoid arthritis had higher disease activity and reported more significant impact on patient-reported outcomes and quality of life than non-Indigenous patients. Spondyloarthropathy features were described in North American populations, with most patients having advanced manifestations. In systemic lupus erythematosus, nephritis was more frequent in Indigenous populations. Gout and osteoarthritis were more severe in New Zealand Maori populations. The existing literature supports differences in disease phenotype and severity in Indigenous populations of Canada, America, Australia and New Zealand. We encourage investigators in this area of research to undertake contemporary studies that disentangle differences between phenotype and severity that are biologic in etiology or merely reflecting differences in access to care and that provide a longitudinal assessment of outcomes in more diverse populations.

Genetic and environmental risk factors for rheumatoid arthritis

Multiple genetic and environmental factors have been associated with an increased risk for rheumatoid arthritis (RA). Of these, the strongest associations have been seen with female sex, a family history of RA, the genetic factor the "shared epitope," and exposure to tobacco smoke. There is also renewed interest in mucosal inflammation and microbial factors as contributors to the development of RA. However, the identification of a "preclinical" period of RA that can be defined as local or systemic autoimmunity as measured by autoantibodies and other biomarkers prior to the development of clinically apparent synovitis suggests that the risk factors for RA are acting long prior to first clinical evidence of IA. As such, a major challenge to the field will be to investigate the full spectrum of the development of RA, from initiation and propagation of autoimmunity during preclinical RA and transition to clinically apparent synovitis and classifiable RA, to determine which genetic and environmental factors are important at each stage of disease development. Understanding the exact role and timing of action of risk factors for RA is especially important given the advent of prevention trials in RA, and the hope that a full understanding of genetic and environmental factors in RA could lead to effective preventive interventions.

Healthcare utilization for arthritis by indigenous populations of Australia, Canada, New Zealand, and the United States: A systematic review☆

PURPOSE

Indigenous populations of Australia, Canada, New Zealand, and the United States of America (USA) experience a higher prevalence of arthritis conditions. Differences in clinical outcomes and mortality may reflect healthcare service use inequities. The objective of this study was to summarize healthcare service use patterns described in the existing literature in order to identify gaps and inform strategies to limit the pronounced negative impact of arthritis on Indigenous populations.

METHODS

Medline, EMBASE, CINAHL, and Indigenous-specific electronic databases (to June 2015) were used to identify cohort, case-control and cross-sectional studies describing healthcare service use by Indigenous populations with specified inflammatory arthritis, osteoarthritis, or rheumatic disease conditions. We extracted information on the study setting and methodology, primary outcome and assessed study quality, and risk of bias.

RESULTS

In total, 19 studies were identified describing three types of healthcare service use: physician visits, hospitalizations, and surgeries. In Canada and New Zealand, Indigenous populations had 36-51% fewer visits to specialists than the non-Indigenous population. Indigenous populations in Canada, New Zealand, and the USA had 37-300% more hospitalizations due to arthritis complications than the non-Indigenous population. Indigenous populations in Australia, Canada, and New Zealand had 27-85% fewer arthroplasties for osteoarthritis than the non-Indigenous population.

CONCLUSIONS

Indigenous populations had higher hospitalization rates but lower use of specialized services for arthritis conditions. Strategies to improve access to specialized arthritis services might reduce health outcome inequities.

Childhood violence and adult chronic pain among indigenous Sami and non-Sami populations in Norway: a SAMINOR 2 questionnaire study

Background

Internationally, studies have shown that childhood violence is associated with chronic pain in adulthood. However, to date, this relationship has not been examined in any indigenous population.

Objective

The main objectives of this study were to investigate the association between childhood violence and reported chronic pain, number of pain sites and the intensity of pain in adulthood in indigenous Sami and non-Sami adults, and to explore ethnic differences.

Design

The study is based on the SAMINOR 2 questionnaire study, a larger population-based, cross-sectional survey on health and living conditions in multiethnic areas with both Sami and non-Sami populations in Mid- and Northern Norway. Our study includes a total of 11,130 adult participants: 2,167 Sami respondents (19.5%) and 8,963 non-Sami respondents (80.5%). Chronic pain was estimated by reported pain located in various parts of the body. Childhood violence was measured by reported exposure of emotional, physical and/or sexual violence.

Results

Childhood violence was associated with adult chronic pain in several pain sites of the body regardless of ethnicity and gender. Childhood violence was also associated with increased number of chronic pain sites and higher pain intensity compared to those not exposed to childhood violence. However, among Sami men, this association was only significant for pain located in chest, hips/legs and back, and non-significant for increased number of chronic pain sites (adjusted model), and higher pain intensity.

Conclusion

Respondents exposed to childhood violence reported more chronic pain in several parts of the body, increased number of chronic pain sites and more intense pain in adulthood than respondents reporting no childhood violence. However, among Sami men, this association was weaker and also not significant for increased number of chronic pain sites and higher pain intensity.