Pain in ankylosing spondylitis: a neuro-immune collaboration

Nociplastic pain in axial spondyloarthritis and psoriatic arthritis: role of JAK kinases in immunopathology and therapeutic impact of JAK inhibitors

INTRODUCTION

Pain in both peripheral and axial joints is a major symptom in patients with psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). Emerging evidence demonstrates pain mechanisms, beyond those related to inflammation or joint damage, based on aberrant processing of nociceptive stimuli peripherally as well as centrally. The Janus kinase/signal transducers and activators of transcription (JAK-STAT) signaling pathway has been implicated in the processing of pain beyond its role in mediating inflammation and inhibitors of this pathway approved for the treatment of axSpA and PsA have been shown to alleviate a broad array of pain outcomes in both axial and peripheral joints.

AREAS COVERED

We review recent definitions and standardization of the nomenclature for categorizing chronic pain according to causality, assessment tools to evaluate nociplastic pain, the pathophysiologic role of JAK-STAT signaling in nociplastic pain, evidence for the presence of nociplastic pain in axSpA and PsA, and the impact of JAK inhibitors (JAKi) on pain outcomes in clinical trials (PubMed: 01/01/2019-04/01-2024).

EXPERT OPINION

Nociplastic pain assessment has been confined almost entirely to the use of a limited number of questionnaires in cross-sectional studies of these diseases. Though effective for alleviating pain, it is unclear if JAKi specifically impact nociplastic pain.

Opioid use surrounding diagnosis and follow-up in patients with ankylosing spondylitis, psoriatic arthritis, and rheumatoid arthritis: Results from US claims databases

OBJECTIVE

To describe patients' use of opioids in the year preceding and year following new diagnosis of ankylosing spondylitis (AS), psoriatic arthritis (PsA), or rheumatoid arthritis (RA), compared with patients without the/se diseases.

METHODS

This study used US IBM® MarketScan® Commercial Claims and Encounters (CCAE) and Medicaid data and included three cohorts, comprised of incident cases of AS, PsA, or RA (2010-2017). Three matched comparator patients (without the incident disease) were selected for each patient within the disease cohort. Opioid use and appropriate treatment exposure (as defined by US guideline recommendations) in the 12-month baseline and follow-up periods were evaluated using descriptive analyses.

RESULTS

Prevalence of claims for opioids was higher for disease cohorts vs. comparators in CCAE; 36.4% of patients with AS, 29.5% with PsA, and 44.4% with RA did not have any claim for guideline-appropriate therapy in follow-up. Prevalence of claims for opioids was also higher for disease cohorts vs. comparators in Medicaid; 30.6% of patients with AS, 36.6% with PsA, and 65.4% with RA did not have any claim for guideline-appropriate therapy in follow-up.

CONCLUSIONS

In patients with AS, PsA, or RA, there was high reliance on opioids at and around the time of diagnosis. Significant proportions of patients were not on appropriate treatment as defined by professional society post-diagnosis guidelines; this discordance between actual patient therapies and treatment recommendations may suggest a need for better awareness of appropriate pain management and treatment strategies in rheumatic diseases. Key Points • This study analysed opioid use among patients with ankylosing spondylitis (AS), psoriatic arthritis (PsA), or rheumatoid arthritis (RA), and adds to current knowledge by expanding beyond assessment of opioid use at diagnosis, to the year before and after diagnosis. • Opioid use was found to be highly prevalent in AS, PsA, and RA in the year prior to diagnosis and, interestingly, was still seen during the year after diagnosis. • Opioids are neither disease modifying, nor a targeted/recommended treatment for chronic autoimmune diseases. In addition to their association with significant economic costs, opioids are potentially hazardous and are not better than alternative treatments with superior safety profiles. • The reasons behind opioid prescribing patterns should be explored further to support movement to targeted therapies.

Single-cell transcriptome revealed dysregulated RNA-binding protein expression patterns and functions in human ankylosing spondylitis

Objective

To explore the expression characteristics and regulatory patterns of RBPs in different immune cell types of AS, and to clarify the potential key role of RBPs in the occurrence and development of AS disease.

Methods

PBMC sample data from scRNA-seq (HC*29, AS*10) and bulk RNA-seq (NC*3, AS*5) were selected for correlation analysis.

Results

(1) Compared with the HC group, the numbers of B, DC (dendritic cells), CD14+ Mono and CD8+ T cells were increased in AS group, while the numbers of platelet (platelets), CD8+ NKT, CD16+ Mono (non-classical monocytes), Native CD4+ T and NK were decreased. (2) Through the analysis of RBP genes in B cells, some RBPs were found to play an important role in B cell differentiation and function, such as DDX3X, SFPQ, SRRM1, UPF2. (3) It may be related to B-cell receptor, IgA immunity, NOD-like receptor and other signaling pathways; Through the analysis of RBP genes in CD8+ T cells, some RBPs that play an important role in the immune regulation of CD8+ T were found, such as EIF2S3, EIF4B, HSPA5, MSL3, PABPC1 and SRSF7; It may be related to T cell receptor, TNF, IL17 and other signaling pathways. (4) Based on bulk RNA-seq, it was found that compared with HC and AS patients, differentially expressed variable splicing genes (RASGs) may play an important role in the occurrence and development of AS by participating in transcriptional regulation, protein phosphorylation and ubiquitination, DNA replication, angiogenesis, intracellular signal transduction and other related pathways.

Conclusion

RBPs has specific expression characteristics in different immune cell types of AS patients, and has important regulatory functions. Its abnormal expression and regulation may be closely related to the occurrence and development of AS.

A lower frequency of inflammatory back pain in male patients with ankylosing spondylitis compared with female patients

In routine rheumatology practice, we noticed that a significant number of male ankylosing spondylitis (AS) patients did not experience inflammatory back pain (IBP). Based on this observation, we aimed to investigate the prevalence of IBP in male AS patients and compare it to that in female patients. Patients with AS who fulfilled the modified New York criteria were subjected to a face-to-face interview with a standardized questionnaire that addressed the IBP components based on the Berlin criteria. The study also included 63 patients with chronic mechanical back pain (MBP). Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were measured, and Bath Ankylosing Spondylitis Disease Activity, Function, and Metrology Indexes (BASDAI, BASFI, and BASMI) were evaluated in patients with AS. There were 181 patients with AS (124 males, mean age 41.2 years; 57 females, mean age 44.6 years) and 63 patients with MBP (28 males, mean age 47.2 years; 35 females, mean age 43.5 years). The prevalence of IBP was found to be 87.7% in female and 66.1% in male patients with AS (p = 0.002). The specificity of the criteria was determined to be high both in females (85.7%) and males (89.2%). Female patients with AS had higher BASDAI levels than males (p = 0.048), but no difference was found in BASFI, BASMI, or serum CRP levels between genders. A considerable proportion of male patients with AS did not experience IBP, although they had similar CRP levels compared with females.

Pain in axial spondyloarthritis: role of the JAK/STAT pathway

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease that is characterized by new bone formation in the axial musculoskeletal system, with X-ray discriminating between radiographic and non-radiographic forms. Current therapeutic options include non-steroidal anti-inflammatory drugs in addition to biological disease-modifying anti-rheumatic drugs that specifically target tumor necrosis factor-alpha (TNFα) or interleukin (IL)-17. Pain is the most critical symptom for axSpA patients, significantly contributing to the burden of disease and impacting daily life. While the inflammatory process exerts a major role in determining pain in the early phases of the disease, the symptom may also result from mechanical and neuromuscular causes that require complex, multi-faceted pharmacologic and non-pharmacologic treatment, especially in the later phases. In clinical practice, pain often persists and does not respond further despite the absence of inflammatory disease activity. Cytokines involved in axSpA pathogenesis interact directly/indirectly with the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling cascade, a fundamental component in the origin and development of spondyloarthropathies. The JAK/STAT pathway also plays an important role in nociception, and new-generation JAK inhibitors have demonstrated rapid pain relief. We provide a comprehensive review of the different pain types observed in axSpA and the potential role of JAK/STAT signaling in this context, with specific focus on data from preclinical studies and data from clinical trials with JAK inhibitors.

Axonal sensory-motor polyneuropathy in ankylosing spondylitis: A case report

Key Clinical Message

In ankylosing spondylitis cases, axonal-type sensory-motor polyneuropathy is a rare manifestation and should be considered an underlying etiology in patients with unexplained neuropathy.

Abstract

This case report discusses a 45-year-old male diagnosed with ankylosing spondylitis (AS), a chronic inflammatory disorder affecting the axial skeleton and peripheral joints. The patient presented with polyneuropathy, characterized by tingling and numbness in the upper and lower limbs, which is an uncommon manifestation of AS. After undergoing various tests, including CT scans and EMG-NCV, no secondary cause for the neuropathy was identified; AS was considered the etiology of the patient's axonal-type sensory-motor polyneuropathy.

Neuropathic pain in axial spondyloarthropathy is underdiagnosed and a confounding factor in biologic drug-switching decision: a cross-sectional study

OBJECTIVES

The aim of this study was to evaluate the relationship between the presence of neuropathic pain (NeP), disease activity scores and biologic drug-switching decisions in the subjects with axial spondyloarthritis (axSpA) receiving biologic treatment.

METHODS

PainDETECT Questionnaire was used to evaluate the presence of NeP in the patients with axSpA aged ≥18 years who had been receiving biologic treatment for at least 6 months. The relationships between disease activity scores, inflammatory markers, life quality index, biologic drug-switching decisions and the presence of NeP were analyzed.

RESULTS

A total number of 175 patients with axSpA [ankylosing spondylitis (AS) (n:150) and non-radiographic axSpA (nr-axSpA) (n:25)] were enrolled in the study. NeP was detected in 41.7% of the patients and it was more common in females than in males (p:0.009). PainDETECT scores were positively correlated with disease activity scores, but they were not correlated with inflammatory marker levels. NeP was found to be significantly more common in whom the biologics had been switched 3 or more times (p:0.007). PainDETECT scores were higher and NeP was more prevalent (p:0.028) in the patients for whom drug-switching decisions had been made due to primary or secondary unresponsiveness.

CONCLUSION

NeP is more common than estimated in the patients with axSpA and current disease activity scores are insufficient to make a distinction between NeP and inflammatory pain. NeP is a confounding factor in the evaluation of treatment response to biologic agents. In the subjects with AS and nr-axSpA with primary or secondary treatment unresponsiveness, the presence of NeP must be considered before biologic drug-switching decisions. Key Points • Neuropathic pain (NeP) is common in subjects with AxSpA treated with multiple biologic agents. • Current disease activity scores for AxSpA are insufficient to make a differentiation between NeP and inflammatory pain. • NeP is a confounding factor in the evaluation of treatment response to biologic agents. • Patients with AxSpA should be re-evaluated in terms of the presence of neuropathic pain before making biologic drug-switching decisions.

Emerging story of gut dysbiosis in spondyloarthropathy: From gastrointestinal inflammation to spondyloarthritis

As a set of inflammatory disorders, spondyloarthritis (SpA) exhibits distinct pathophysiological, clinical, radiological, and genetic characteristics. Due to the extra-articular features of this disorder, early recognition is crucial to limiting disability and improving outcomes. Gut dysbiosis has been linked to SpA development as evidence grows. A pathogenic SpA process is likely to occur when a mucosal immune system interacts with abnormal local microbiota, with subsequent joint involvement. It is largely unknown, however, how microbiota alterations predate the onset of SpA within the “gut-joint axis”. New microbiome therapies, such as probiotics, are used as an adjuvant therapy in the treatment of SpA, suggesting that the modulation of intestinal microbiota and/or intestinal barrier function may contribute to the prevention of SpA. In this review, we highlight the mechanisms of SpA by which the gut microbiota impacts gut inflammation and triggers the activation of immune responses. Additionally, we analyze the regulatory role of therapeutic SpA medication in the gut microbiota and the potential application of probiotics as adjunctive therapy for SpA.

Aberrant functional connectivity between anterior cingulate cortex and left insula in association with therapeutic response to biologics in inflammatory arthritis

BACKGROUND

Brain activity is reported to be associated with individual pain susceptibility and inflammatory status, possibly contributing to disease activity assessment in inflammatory arthritis (IA) including rheumatoid arthritis (RA) and spondyloarthritis (SpA). However, what alteration of brain function associated with disease activity and therapeutic effectiveness in IA remains unclear. We aimed to identify the alterations of brain functional connectivity (FC) shared in both RA and SpA, and evaluate its relationship to anti-rheumatic treatment response using functional magnetic resonance imaging (MRI).

PATIENTS AND METHODS

Structural and resting-state functional MRI data were acquired from patients with IA, patients with osteoarthritis (OA) and heathy controls (HCs). Two datasets were adopted to derive (51 IA, 56 OA, and 17 HCs) and validate (31 IA) the observations. 33 IA patients in the derivation dataset and all the patients in validation dataset required biological treatment and were clinically evaluated before and after therapy. Via whole-brain pair-wise FC analyses, we analyzed IA-specific FC measures relevant to therapeutic response to biologics.

RESULTS

The value of FC between left insular cortex (IC) and anterior cingulate cortex (ACC) was significantly low in IA patients compared with OA patients and HCs. We demonstrated that the FC between left anterior long insular gyrus as a subdivision of IC and ACC was significantly associated with therapeutic response to biologics regarding the improvement of patients' global assessment (PGA) in both derivation and validation datasets.

CONCLUSION

Disease-specific resting-state FC provides a means to assess the therapeutic improvement of PGA and would be a clinical decision-making tool with predictability for treatment response in both RA and SpA.

Exploring sex differences in alpha brain activity as a potential neuromarker associated with neuropathic pain

ABSTRACT

Alpha oscillatory activity (8-13 Hz) is the dominant rhythm in the awake brain and is known to play an important role in pain states. Previous studies have identified alpha band slowing and increased power in the dynamic pain connectome (DPC) of people with chronic neuropathic pain. However, a link between alpha-band abnormalities and sex differences in brain organization in healthy individuals and those with chronic pain is not known. Here, we used resting-state magnetoencephalography to test the hypothesis that peak alpha frequency (PAF) abnormalities are general features across chronic central and peripheral conditions causing neuropathic pain but exhibit sex-specific differences in networks of the DPC (ascending nociceptive pathway [ANP], default mode network, salience network [SN], and subgenual anterior cingulate cortex). We found that neuropathic pain (N = 25 men and 25 women) was associated with increased PAF power in the DPC compared with 50 age- and sex-matched healthy controls, whereas slower PAF in nodes of the SN (temporoparietal junction) and the ANP (posterior insula) was associated with higher trait pain intensity. In the neuropathic pain group, women exhibited lower PAF power in the subgenual anterior cingulate cortex and faster PAF in the ANP and SN than men. The within-sex analyses indicated that women had neuropathic pain-related increased PAF power in the ANP, SN, and default mode network, whereas men with neuropathic pain had increased PAF power restricted to the ANP. These findings highlight neuropathic pain-related and sex-specific abnormalities in alpha oscillations across the DPC that could underlie aberrant neuronal communication in nociceptive processing and modulation.

The American College of Rheumatology Fibromyalgia Criteria Are Useful in the Evaluation of Fibromyalgia Symptoms in Patients With Ankylosing Spondylitis: A Cross-Sectional Study

BACKGROUND

Fibromyalgia (FM) is common among patients with ankylosing spondylitis (AS), and its coexistence is believed to interfere with the measurement of patient-reported outcomes of disease activity and function in AS because of overlapping symptoms between the 2 diseases. This can confound clinical assessment and treatment decisions.

AIMS

The aim of this study was to assess the relationship between the Fibromyalgia Symptom Scale (FSS) and its components, the Widespread Pain Index (WPI), and System Severity Scale with measures of disease activity, function, and patient-reported outcomes in AS.

METHODS

We recruited 63 AS patients (aged ≥18 years) meeting the modified New York criteria, and Bath Ankylosing Spondylitis Disease Activity Index, Ankylosing Spondylitis Disease Activity Score-C-Reactive Protein, Routine Assessment of Patient Index Data 3, and Bath Ankylosing Spondylitis Functional Index questionnaires were administered to them. The presence of FM was determined using validated 2010 American College of Rheumatology diagnostic criteria for FM.

RESULTS

Twenty-eight of 63 patients (44.4%) with AS and FM had higher disease activity and greater impairment of functional ability compared with AS patients without FM. Using multiple linear regression estimates, there was no significant relationship of FSS scores with Bath Ankylosing Spondylitis Disease Activity Index (p = 0.36), Routine Assessment of Patient Index Data 3 (p = 0.50), Ankylosing Spondylitis Disease Activity Score-C-Reactive Protein (p = 0.24), Bath Ankylosing Spondylitis Functional Index (p = 0.42) scores, or erythrocyte sedimentation rate (p = 0.82) and C-reactive protein (p = 0.75).

CONCLUSIONS

Despite a high prevalence of FM in our patients with the diagnosis of AS, there was no relationship between FSS and measures of disease activity or function in AS, suggesting that FSS and its components could be a useful tool to assess FM in AS patients. Also, FM impairs functional ability in patients with AS.

Central Sensıtızatıon ın Axıal Spondyloarthrıtıs: An Exploratıve Study wıth Quantıtatıve Sensory Testıng and Clınıcal Scales

OBJECTIVE

To evaluate the central sensitization (CS) and the related parameters in patients with axial spondyloarthritis (axSpA).

METHODS

Quantitative sensory testing (QST) which consists of pressure pain threshold (PPT), temporal summation (TS), and conditioned pain modulation (CPM) were applied to the participants. Disease activity, functional status, sleep quality, pain, depression, and fatigue were assessed. Patients were divided as the ones with and without CS according to the central sensitization inventory (CSI) and the results were compared.

RESULTS

One hundred patients and fifty controls were recruited. Sixty axSpA patients had CS. When QST results were compared between the patient and control groups, all PPT scores were found lower (p<0.05) in patients. Regarding the comparison of the patients with and without CS, sacroiliac, and trapezius PPT scores were found lower in the patients with CS (p<0.05). On the other hand, there was no significant difference in the mean TS scores (p>0.05) between patients and controls, and in patients with and without CS. All investigated comorbidities were found to be significantly more frequent (p<0.001) in the patients with CS. In regression analysis female gender, morning stiffness duration, CPM, depression, and fatigue were detected as related parameters with CSI scores.

CONCLUSION

CS and related comorbidities were found to be increased in axSpA patients. This increase should be taken into consideration in the management of these patients.

Assessment of Neuropathic Pain in Ankylosing Spondylitis: Prevalence and Characteristics

INTRODUCTION

Pain in ankylosing spondylitis is currently considered an inflammatory pain (IP). However, it was found that some patients still had the sensation of pain even without inflammation. Our study was to investigate the prevalence and characteristics of neuropathic pain (NeP) in Chinese Han ankylosing spondylitis (AS) patients.

METHODS

The study consisted of three parts. Firstly, we assessed the prevalence and clinical data of NeP in 182 AS patients. Secondly, we evaluated pain improvement after etanercept therapy in 63 patients. Finally, serum neurotransmitters were measured for 20 AS patients and ten healthy controls (HC).

RESULTS

Out of 182 AS patients, our study showed that 14 patients (7.70%) had likely NeP and 55 (30.21%) had uncertain NeP. There were significant differences among the three groups with respect to nocturnal pain (NP), peripheral pain (PP), total back pain (TBP), BASDAI, ASDAS-CRP, HAD-A, HAD-D, and BASDAI-fatigue except fort CRP concentrations. Principal component analysis (PCA) of AS pain revealed that the weight of NeP was greater than PP in the first principal component (0.703 vs. 0.639). Structural equation modeling (SEM) revealed that NeP altered disease activity (β = 0.62, P < 0.001), which influenced psychological status (β = 0.42, P < 0.001). Of 63 patients who used etanercept for 3 months, significant improvement was found in NP, TBP, and PP (all P < 0.0001) but not in PDQ (10.60 ± 6.85 vs. 9.98 ± 6.40, P = 0.0671). Serum norepinephrine concentrations in patients with PDQ > 19 were higher than those in patients with PDQ ≤ 19 and HC.

CONCLUSIONS

We conclude that NeP contributes to pain in AS patients.

Pain and Fatigue in Patients With Ankylosing Spondylitis Treated With Tumor Necrosis Factor Inhibitors: Multinational Real-World Findings

BACKGROUND/OBJECTIVE

Patients with ankylosing spondylitis (AS) experience symptoms and comorbidities that impact their health-related quality of life (HRQoL) and ability to work. This real-world, global survey was conducted among AS patients receiving tumor necrosis factor inhibitors (TNFis) to evaluate both the frequency and severity of persistent symptoms, and the impact of pain and fatigue on HRQoL, employment status, and work activity.

METHODS

Patients with AS and their treating physicians from 13 countries across 5 continents completed questionnaires capturing demographics, patient symptoms, current disease status, HRQoL, current therapy, employment status, and Work Productivity and Activity Impairment.

RESULTS

Seven hundred five patients who had been receiving a TNFi for 3 months or more and completed both Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) pain and fatigue domains were included in the analysis; of these, 37.6% reported high BASDAI pain scores and 41.3% high BASDAI fatigue scores. Medical Outcomes Study-Short Form, 36-item version 2 domain, 5-dimensional EuroQoL Questionnaire, and 5-dimensional EuroQoL visual analog scale scores were significantly lower (p < 0.0001), and Work Productivity and Activity Impairment scores significantly higher (p < 0.0001), in patients with high levels of pain or fatigue than low levels.

CONCLUSIONS

Globally, levels of pain and fatigue remained high in AS patients receiving TNFi treatment, which were significantly associated with reduced HRQoL and work productivity. Such persistent symptoms in usual care suggest a substantial unmet need in AS pharmacologic and nonpharmacologic therapeutic pathways.

Opioid use frequency in early axial spondyloarthritis in Finland - a pharmacoepidemic register study

OBJECTIVES

To evaluate opioid use among incident axial spondyloarthritis (axSpA) patients compared to general population.

METHODS

From the national register, we identified all adult patients with axSpA (ICD-10 codes M45-46), who between 2010 and 2014 (index date, ID) were for the first time granted special reimbursement for any disease-modifying anti-rheumatic drugs (DMARDs). Three matched population controls were identified for each patient. Drug purchases were evaluated between 2009-15, and opioid use was analyzed for one year before and after the ID. The Defined Daily Dose (DDD) was used as a tool to assess the opioid consumption before and after the biological (b) DMARD initiation.

RESULTS

We identified 3,577 axSpA patients and 10,573 controls. Of these patients, 97.2% started a conventional synthetic (cs) DMARD during a year after ID and 23.4% switched later to a self-injected bDMARD between the ID and 31 Dec 2015 (median follow-up 3.4 years). Opioids were purchased at least once by 29.8% and 21.7% of the patients in the years before and after the ID, respectively, compared to 8.1% and 7.8% of the controls. The proportion of opioid-using patients was greatest during the last quarter before the ID [relative risk (RR) 4.72 (95% CI 4.14 to 5.39)] compared to controls, and it remained higher [RR 2.84 (2.59 to 3.11)] also after the start of csDMARDs. DDD of opioid consumption decreased from 7.7 to 1.6/1,000 inhabitants after bDMARD initiation.

CONCLUSION

Considerably more axSpA patients than population controls used opioids. The opioid consumption by dose decreased clearly after bDMARD initiation.

Sociodemographic determinants in the evolution of pain in inflammatory rheumatic diseases: results from ESPOIR and DESIR cohorts

Objective

To determine whether socio-demographic factors are associated with heterogeneity in pain evolution in inflammatory rheumatic diseases (IRDs) after accounting for disease-specific characteristics in a system with universal health care.

Methods

This analysis included the data from two prospective observational cohorts of early IRDs (ESPOIR for early RA and DESIR for early SpA). Data on pain was measured, respectively, on 13 and 9 occasions spanning 10 and 6 years of follow-up using the Short-Form 36 bodily pain score for 810 participants of ESPOIR, and 679 participants of DESIR. Linear mixed models were used to characterize differences in pain evolution as a function of age (tertiles), sex, ethnicity, education, marital, and professional status, after accounting for disease-related, treatment, lifestyle, and health factors.

Results

While transitioning from early (disease duration ≤6 months for RA and ≤3 years for SpA) to long-standing disease, differences in pain evolution emerged as a function of age (P < 0.001), sex (P = 0.050), and ethnicity (P = 0.001) in RA, and as a function of age (P = 0.048) in SpA; younger age, males, and Caucasians exhibited lower pain in the latter phases of both diseases. Highly educated participants (RA, β = −3.8, P = 0.007; SpA, β = −6.0, P < 0.001) for both diseases, and Caucasians (β = −5.6, P = 0.021) for SpA presented with low pain early in the disease, with no changes throughout disease course.

Conclusion

Being older, female, non-Caucasian and having lower education was found to be associated with worse pain in early and/or long-standing IRDs, despite universally accessible health-care. Early identification of at-risk populations and implementation of multidisciplinary strategies may reduce patient-reported health outcome disparities.

Trial registration registrations

ESPOIR: ClinicalTrials.gov, www.clinicaltrials.gov, NCT03666091. DESIR: ClinicalTrials.gov, www.clinicaltrials.gov, NCT01648907.

Sex-Specific Abnormalities and Treatment-Related Plasticity of Subgenual Anterior Cingulate Cortex Functional Connectivity in Chronic Pain

The subgenual anterior cingulate cortex (sgACC) is a key node of the descending antinociceptive system with sex differences in its functional connectivity (FC). We previously reported that, in a male-prevalent chronic pain condition, sgACC FC is abnormal in women but not in men. This raises the possibility that, within a sex, sgACC FC may be either protective or represent a vulnerability to develop a sex-dominant chronic pain condition. The aim of this study was to characterize sgACC FC in a female-dominant chronic pain condition, carpal tunnel syndrome (CTS), to investigate whether sgACC abnormalities are a common feature in women with chronic pain or unique to individuals with pain conditions that are more prevalent in the opposite sex. We used fMRI to determine the resting state FC of the sgACC in healthy controls (HCs, n = 25, 18 women; 7 men) and people with CTS before (n = 25, 18 women; 7 men) and after (n = 17, 13 women; 4 men) successful surgical treatment. We found reduced sgACC FC with the medial pre-frontal cortex (mPFC) and temporal lobe in CTS compared with HCs. The group-level sgACC-mPFC FC abnormality was driven by men with CTS, while women with CTS did not have sgACC FC abnormalities compared with healthy women. We also found that age and sex influenced sgACC FC in both CTS and HCs, with women showing greater FC with bilateral frontal poles and men showing greater FC with the parietal operculum. After surgery, there was reduced sgACC FC with the orbitofrontal cortex, striatum, and premotor areas and increased FC with the posterior insula and precuneus compared with pre-op scans. Abnormally reduced sgACC-mPFC FC in men but not women with a female-prevalent chronic pain condition suggests pain-related sgACC abnormalities may not be specific to women but rather to individuals who develop chronic pain conditions that are more dominant in the opposite sex. Our data suggest the sgACC plays a role in chronic pain in a sex-specific manner, and its communication with other regions of the dynamic pain connectome undergoes plasticity following pain-relieving treatment, supporting it as a potential therapeutic target for neuromodulation in chronic pain.

Neuropathic Pain and its Relationship With Fibromyalgia, Vitamin D Status and Medication Use in Patients With Ankylosing Spondylitis

Objective

To determine the frequency of neuropathic pain (NeP) and potentially related new factors including fibromyalgia, vitamin D and medication use in ankylosing spondylitis (AS) patients.

Methods

In total, 102 patients with AS were prospectively enrolled in this study and evaluated for pain severity (visual analog scale, VAS), disease activity (the Bath Ankylosing Spondylitis Disease Activity Index, BASDAI), fibromyalgia and current medication use The presence of NeP was also assessed using the painDETECT questionnaire Blood samples were taken from all patients to analyze serum 25-hydroxyvitamin D and inflammatory marker levels.

Results

NeP component 32 (21 [20.6%]; clearly NeP and 11 [10.8%]; mixed NeP) was present in patients with AS Compared to those without NeP, they had significantly higher VAS and BASDAI scores (p=0.022 and 0.003, respectively) In addition, there was a highly significant difference of frequency of fibromyalgia between patients with and without NeP (50.0% vs 5.7%, p<0.001) Vitamin D status and medication use were comparable for patients with and without NeP Logistic regression analysis revealed that only fibromyalgia was a significant predictor of NeP.

Conclusion

This study confirmed that about one-third of AS patients have the NeP component In addition, NeP was found to be associated with the frequency of fibromyalgia However, no relation was found between NeP and vitamin D status and medication use in AS.

The Prognostic Value of Pain Phenotyping in Relation to Treatment Outcomes in Patients with Axial Spondyloarthritis Treated in Clinical Practice: A Prospective Cohort Study

Despite the control of inflammation, many patients with axial spondyloarthritis (axSpA) still report pain as a significant concern. Our objective was to explore the prognostic value of the painDETECT questionnaire (PDQ) in relation to treatment outcomes in axSpA patients treated in clinical practice. AxSpA patients with high disease activity initiating or switching a biological Disease-Modifying Antirheumatic Drug (bDMARD) were eligible. The PDQ score (range: −1 to 38) was used to distinguish participants with nociceptive pain (NcP) mechanisms from participants with a mixed pain mechanism (MP). The primary outcome was the proportion of individuals achieving a 50% improvement of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI50) at 12 weeks; logistic regression analysis models were used to determine the prognostic value of the nociceptive pain phenotype. Changes in continuous outcomes such as the Assessment of SpondyloArthritis International Society (ASAS) core outcome domains were analyzed using analysis of covariance (ANCOVA). Health-related quality of life (HR-QoL) was addressed using the Medical Outcomes Study SF-36. During a period of 22 months, 49 axSpA patients were included. Twenty (41%) had an NcP phenotype according to the PDQ score. BASDAI50 responses were reported by 40% (8/20) and 28% (8/29) NcP and MP groups, respectively. However, a prognostic value was not found in relation to the primary outcome (crude odds ratio [95% confidence interval]: 1.75 [0.52 to 5.87]). Across most of the secondary outcomes, axSpA NcP phenotype patients were reported having the most improvements in the HR-QoL measures. These data indicate the influence of personalized management strategies according to patients’ pain phenotypes for stratification of axSpA patients in randomized controlled trials.

Patients With Ankylosing Spondylitis Are Associated With High Risk of Fibromyalgia: A Nationwide Population-Based Cohort Study

Objectives: The main purpose of this retrospective cohort study was to provide an evaluation of Ankylosing spondylitis (AS) patients' fibromyalgia risk in different age and sex subgroups by analyzing large study samples.

Methods: Datasets from the National Taiwan Insurance Research Database (NHIRD) were retrieved in this retrospective cohort study. This study was approved by the Institutional Review Board of Chung Shan Medical University (IRB permit number CS15134). Within the Longitudinal Health Insurance Database (LHID), and the subset of NHIRD, we identified AS patients to explore the risk of further fibromyalgia. The exposure cohort included patients with newly-diagnosed AS (ICD-9-CM:720.0) during 2000–2013. After 1:4 age-sex matching and 1:2 propensity score matching, and adjusting potential confounders, individuals without AS were identified as a comparison cohort. The adjusted hazard ratio of subsequent development of fibromyalgia in people with AS was evaluated. Further stratification analyses of different ages and genders were then undertaken to validate the results.

Results: In total, 17 088 individuals were included in the present study, including 5,696 patients with AS and 11,392 individuals without AS. Respective incidence rates (per 1,000 person-months) of fibromyalgia was 0.52 (95% CI, 0.46–0.59) in the AS cohort and 0.39 (95% CI, 0.35–0.44) in the non-AS cohort. Compared with the non-AS cohort, aHR of developing fibromyalgia was 1.32 (95% CI, 1.12–1.55) in people with AS. This association was consistent in both statistical models of 1:4 age–sex matching and 1:2 propensity score matching.

Conclusion: Patients with AS were associated with a higher risk of fibromyalgia, especially those over 65 years old. In managing patients with AS, clinicians should be aware of this association, which could impact diagnosis, disease activity evaluation, and treatment.

Pain in Axial Spondyloarthritis: Insights from Immunology and Brain Imaging

Inflammatory back pain is characteristic of spondyloarthritis (SpA); however, this pain may not respond to treatment with NSAIDs or biologics. Pain is multifactorial and a combination of mechanical and inflammatory factors. A growing body of literature examines the impact of emotions on pain in SpA; many patients with this condition suffer from depression and fibromyalgia. Advanced imaging techniques can investigate the interplay of various brain networks in pain perception. Animal models have helped understand the interplay between the immune and nervous systems in pain generation and have highlighted differences in pain perception between the sexes.

Is central sensitization an important determinant of functional disability in patients with chronic inflammatory arthritides?

Background

Central sensitization (CS) is a condition characterized by a disproportionate response to pain stimuli. We sought to investigate the prevalence of CS in patients with inflammatory arthritides and its association with measures of disease activity and functional disability.

Methods

We conducted an observational retrospective study in psoriatic arthritis (PsA) and rheumatoid arthritis (RA) patients. We administered to all the subjects in the study the CS inventory (CSI), a questionnaire that has been used for the diagnosis of CS. Demographic and clinical characteristics were collected as well as measures or disease activity [i.e. Simple Disease Activity Index, Disease Activity Score in PsA (DAPSA)] and functional disability [Health Assessment Questionnaire Disability Index (HAQ-DI)]. Patients with fibromyalgia were excluded from the analyses. The primary outcome measure was the presence of functional disability as assessed by HAQ-DI >1.

Results

We enrolled 150 patients with inflammatory arthritides (78 PsA and 72 RA). Prevalence of CS was observed in 35.3% of the overall sample (29% in RA, 42.9% in PsA). Binary logistic regressions showed a strong, independent and linear association between functional disability and CS in both PsA and RA patients. The strength of this association was greater in PsA than in RA.

Conclusion

CS is an important determinant of functional disability in patients with chronic inflammatory arthritides. PsA appeared to be more vulnerable to CS. In addition, in the presence of CS, DAPSA did not adequately capture the occurrence of functional disability. Therefore, special attention should be paid to PsA patients, in whom the concomitant diagnosis of CS should be routinely ruled out.

Quality of internet videos related to exercise therapy of ankylosing spondylitis from mainland China : Content analysis

OBJECTIVE

The aim of this study is to assess the quality and reliability of online videos on ankylosing spondylitis (AS) exercises from the five most popular video websites in China.

DESIGN

Cross-sectional and descriptive study.

METHODS

We searched the video websites of Youku, Tencent, Tudou, IQiYi, and bilibili on February 15, 2020, using the keywords "Ankylosing spondylitis exercise" "Ankylosing spondylitis rehabilitation" and "Ankylosing spondylitis therapy" A total of 114 videos were included in the study and evaluated according to the Global Quality Scale (GQS) and modified DISCERN tool.

RESULTS

According to the GQS, the videos were classified as high quality (12.3%, n = 14), intermediate quality (63.2%, n = 72), and low quality (24.6%, n = 28). Using the modified DISCERN tool, the videos were divided into useless (53.5%, n = 61), useful (35.1%, n = 40), and misleading (11.4%, n = 13).

CONCLUSION

The analysis shows that the quality and reliability of online videos related to exercise therapy for Ankylosing spondylitis (AS) should be improved and supervised in China. Hospitals, universities, and medical doctors should make more useful and high-quality videos to provide effective exercise guidance for AS patients.

Association between clinical characteristics and pain relief in patients with axial spondyloarthritis treated with non-steroidal anti-inflammatory drugs

Objectives

The aim of this study was to evaluate pain relief in axial spondyloarthritis (axSpA) patients treated with non-steroidal anti-inflammatory drugs (NSAIDs) and to investigate the relation of the demographic, clinical, and psychological characteristics with pain relief.

Patients and methods

Between February 2017 and December 2019, a total of 94 patients (61 males, 33 females; mean age: 28.3±8.1 years; range, 14 to 54 years) who were diagnosed with axSpA and treated with NSAIDs were included. The patients were assessed at baseline and at three months. A reduction of 30% in the Numeric Rating Scale (NRS) indicates a clinically meaningful improvement. The patients were divided into the relief group (≥30% improvement in NRS) and non-relief group (<30% improvement). Potential influential factors for pain relief such as neuropathic pain (NP), disease activity, function, pain catastrophizing, and pain self-efficacy were assessed. The relationship between patients’ characteristics and pain relief was analyzed.

Results

Seventy-two (76.6%) patients achieved pain relief. These patients had significantly higher baseline erythrocyte sedimentation rate, C-reactive protein, and lower percentage of NP. There was no significant difference between the two groups in function, pain catastrophizing, and pain self-efficacy. Multiple logistic regression analysis revealed that patients with NP were less likely to achieve pain relief (odds ratio [OR]: 3.531, 95% confidence interval [CI]: 1.155-10.789; p=0.027).

Conclusion

Pain relief is still insufficient in some axSpA patients, despite the administration of NSAIDs. The presence of NP is significantly associated with poor pain relief. Alternative medications instead of NSAIDs are needed to achieve optimal pain relief, when NP is diagnosed.

Somatosensory dysfunction related neuropathic pain component affects disease activity, functional status and quality of life in ankylosing spondylitis

AIM

To investigate the neuropathic pain (NP) component in ankylosing spondylitis (AS) and to assess the relations between NP and disease characteristics.

METHODS

Eighty participants were included in this study. Demographic properties, duration of disease, laboratory values and clinical assessments (visual analog scale [VAS], Bath Ankylosing Spondylitis Disease Activity Index [BASDAI], Bath Ankylosing Spondylitis Functional Index [BASFI], Bath Ankylosing Spondylitis Metrology Index [BASMI], Short Form [SF]-36 questionnaire, Beck Depression Inventory [BDI]) were recorded. The NP component was assessed by both DN4 and PainDETECT questionnaires (PD-Q) and patients were classified into groups according to questionnaire scores.

RESULTS

NP component was detected by the DN4 and PD-Q in 40% and 28.7% of our patients, respectively. Likely-NP group had significantly higher scores in VAS-pain, BASDAI, BASFI, BASMI and BDI compared with both uncertain-NP and unlikely-NP groups. There was no significant difference between the SF-36 scores of the likely-NP and uncertain-NP groups. Moreover, all SF-36 scores were significantly lower in the likely-NP group than in the unlikely-NP group. Based on DN4 scale, patients with NP had significantly higher erythrocyte sedimentation rate (ESR), VAS, BASDAI, BASFI, BASMI scores and significantly lower SF-36 (except social functioning) scores compared to patients without NP. Both painDETECT and DN4 scores of the patients were significantly positively correlated with ESR, VAS, BASDAI, BASFI, BASMI, BDI scores and negatively correlated with all SF-36 scores.

CONCLUSIONS

Our results revealed that the presence of NP component in patients with AS is associated with various disease-related variables, including pain, high disease activity, reduced mobility of the axial skeleton, depression and poor quality of life.

Interleukin-1β, interleukin-6, and interleukin-17A as indicators reflecting clinical response to celecoxib in ankylosing spondylitis patients

BACKGROUND

This study was to investigate the value of 10 serum inflammatory cytokines for predicting clinical response to celecoxib in ankylosing spondylitis (AS) patients.

METHODS

Totally, 103 active AS patients who underwent celecoxib treatment for 12 weeks were enrolled. Then, pre-treatment serum TNF-α, IL-1β, IL-6, IL-8, IL-17A, IL-21, IL-23, IL-32, ICAM-1, and VEGF were detected by enzyme-linked immunosorbent assay. Besides, the ASAS 20 response was assessed at week 2 (W2), week 6 (W6), and week 12 (W12). Based on the ASAS 20 response at W12, patients were divided into responders and non-responders.

RESULTS

After celecoxib treatment, 53 (51.3%), 58 (56.3%), and 60 (58.3%) patients achieved ASAS 20 response at W2, W6, and W12, respectively. Furthermore, IL-1β (P = 0.019), IL-6 (P = 0.004), and IL-17A (P = 0.007) levels were higher, while TNF-α (P = 0.086), IL-8 (P = 0.143), IL-21 (P = 0.687), IL-23 (P = 0.329), IL-32 (P = 0.216), ICAM-1 (P = 0.119), and VEGF (P = 0.732) levels were similar in responders compared with non-responders. Subsequent multivariate logistic regression analysis revealed that among these inflammatory cytokines, only IL-6 (P = 0.019) independently predicted higher ASAS 20 response to celecoxib at W12, and it had a fair value for predicting ASAS 20 response to celecoxib at W12 (area under the curve: 0.666, 95% confidence interval: 0.561-0.771) by receiver-operating characteristic curve analysis.

CONCLUSION

Serum IL-1β, IL-6, and IL-17A serve as indicators for predicting clinical response to celecoxib in AS patients, which may assist with the optimization of personalized treatment.

Pain- and Fatigue-Related Functional and Structural Changes in Ankylosing Spondylitis: An fRMI Study

Background: Chronic pain and fatigue are two cardinal features of ankylosing spondylitis (AS) and how to effectively treat these conditions continues to be a challenge. The underlying mechanisms and the relationship between AS-related pain and fatigue remain poorly understood. The present study was conducted, therefore, to explore the brain functional and structural changes associated with pain and fatigue in AS.

Methods: A total of 65 AS patients (48 men and 17 women; 32.33 ± 8.6 years) and 53 age- and sex-matched controls were enrolled in the study. The patients underwent clinical assessment based on Total Back Pain scores, Fatigue Severity Scale, Bath Ankylosing Spondylitis Disease Activity Index, (BASDAI), high-sensitivity C-reactive Protein (hsCRP), erythrocyte sedimentation rate (ESR), and Beck Depression Inventory (BDI). Using 3T magnetic resonance imaging (3T-MRI), we analyzed the brain functional (connectivity and nodal properties) and structural (covariance and gray matter volumes) differences between AS patients and controls. Furthermore, we extracted the values of the significantly changed regions in the AS cohort and explored their association with pain and fatigue.

Results: In AS patients, there were functional and structural abnormalities distributed in the default mode network (DMN), salience network (SN), sensory/somatomotor network (SMN), dorsal attention network (DAN), task control network (TCN), and visual network, and some regions showed both types of changes. Among these, the functional connectivity (FC) between the left insula and medial prefrontal cortex, the betweenness centrality of the left medial prefrontal cortex and the gray matter volume of the right putamen tracked both pain and fatigue. In addition, pain was related to within-DMN FC disruption and nodal function / gray matter volumes changes in DMN, SN, and the visual network, while fatigue mainly involved the SMN, DAN, and TCN. Moreover, certain changes were also related to BASDAI and inflammation level.

Conclusion: This study offers new insights into understanding the neural mechanism of AS-related pain and fatigue, and could help to stratify patients based on the correlation features and ultimately move towards a personalized therapy.

Neuropathic component of low back pain in patients with ankylosing spondylitis

OBJECTIVE

The aim of this cross sectional study was to evaluate frequency of neuropathic back pain in ankylosing spondylitis (AS) patients and to determine the relation with disease variables and occurrence of neuropathic pain.

METHODS

Fifty-eight AS patients who were not having any comorbid disease and/or using drugs that would cause neuropathy, were recruited to the study. Demographic properties and clinical characteristics (functional status and disease activity assessed by BASFI and BASDAI respectively, ESR, CRP) and quality of life determined by AS quality of life-QoL questionnaire, were recorded. The neuropathic property of back pain was assessed by both Leeds Assessment of Neuropathic symptoms and signs (LANSS) and Douleur Neuropathique 4 (DN4) scales.

RESULTS

58 AS patients (17 female, 41 male) with a mean age of 45 ± 18 years were included. 33 patients (56.9%) and 31 patients (53.4%) were defined as having neuropathic pain depending on the LANSS (scores > 12) and DN4 (scores > 4) questionnaire scores respectively. The mean score of LANSS scale was correlated with ASQoL, BASFI, BASDAI, and DN4; and the mean score of DN4 scale was correlated with ASQoL, BASFI and LANSS. The mean levels of BASFI and ASQoL scores were significantly higher in patients having neuropathic pain than in patients not having (p < .05).

CONCLUSION

Neuropathic pain is common and determined in more than half of the patients with AS and related with functional status and quality of life. Diagnosis and treatment of neuropathic pain are warranted in order to increase functional ability and quality of life in patients suffering from AS.

Correlation Between Chronic Pain Acceptance and Clinical Variables in Ankylosing Spondylitis and Its Prediction Role for Biologics Treatment

Objectives: Studies have proven that improving patients' acceptance of chronic pain could be an effective therapy for alleviating pain and other symptoms. Our objectives were to investigate the correlation between chronic pain acceptance and clinical variables in ankylosing spondylitis (AS), and the prediction role of chronic pain acceptance for biologics treatment.

Methods: First, 167 AS patients were recruited to complete a series of questionnaires, including the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Chronic Pain Acceptance Questionnaire (CPAQ), Hospital Anxiety and Depression Scale (HADS), and Tampa Scale for Kinesiophobia (TSK). Bivariate correlation analysis was utilized to investigate the correlation between pain acceptance and clinical variables. Based on the level of chronic pain acceptance and serum C-reactive protein (CRP), patients were separated into four subgroups. Then, another 68 patients initiating anti-tumor necrosis factor (TNF) treatment were recruited to complete the questionnaires at baseline (T0) and 3 months after treatment (T3). The changes in clinical variables and treatment response were compared between multiple subgroups.

Results: Chronic pain acceptance had strong correlations with anxiety, depression and fear of movement, and moderate correlations with BASFI and pain intensity. Both activity engagement (AE) and pain willingness (PW) had significant correlations with pain intensity, BASFI and psychological status. In addition, AE had a significant correlation with disease duration, while PW had a significant correlation with ASDAS-CRP. Subgroup analysis showed that patients with low chronic pain acceptance and high levels of serum CRP had the highest BASDAI. Among patients initiating anti-TNF treatment, those with high pain acceptance and high levels of serum CRP achieved the most obvious reduction in BASDAI after 3 months treatment.

Conclusion: Pain acceptance is a new tool to assess pain in AS which may also reflect physical and psychological status. Clinicians should identify high-risk patients with low chronic pain acceptance and high levels of serum CRP, and give psychological and pharmacological intervention promptly. Moreover, the combination of baseline chronic pain acceptance and serum CRP level could be used to predict the treatment response in AS patients initiating biologics treatment.

Relationship between Vitamin D levels and pain and disease activity in patients with newly diagnosed axial spondyloarthritis

OBJECTIVES

To explore the relationship between Vitamin D levels and pain and disease activity in patients with newly diagnosed axial spondyloarthritis (axSpA).

METHODS

A convenience sample of 131 newly diagnosed axSpA patients and 60 healthy controls was recruited from July 2016 to December 2018. Serum 25-hydroxyvitamin D [25(OH)D] was measured to assess vitamin D levels. Disease activity was assessed by objective indicators [Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the Bath Ankylosing Spondylitis Metrology Index (BASMI)], patient-reported questionnaires [the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and the Bath Ankylosing Spondylitis Functional Index (BASFI)]. Pain intensity and interference were also assessed.

RESULTS

Vitamin D insufficiency [serum 25(OH) D levels<50 nmol/L]was found in 46 (35.1%) and 25 (43.3%) of the axSpA patients and the healthy controls, respectively. Female patients had higher risk (OR:4.928; 95% CI: 1.921-12.642) for vitamin D insufficiency than male patients. Vitamin D was positively correlated with CRP, ESR level, the BASFI, and the BASMI. Logistic regression showed that vitamin D levels were not associated with pain, or disease activity in the newly diagnosed axSpA patients. Gender was the only predictive variable for vitamin D levels.

CONCLUSIONS

Vitamin D insufficiency was prevalent in both newly diagnosed axSpA patients and healthy controls. There was no association between vitamin D and pain and disease activity in the newly diagnosed axSpA patients. Monitoring vitamin D levels is important and early intervention for vitamin D insufficiency is needed, especially in female patients.

Musculoskeletal pain: determination of clinical phenotypes and the rational treatment approach

Personalized treatment is one of the basic principles of modern medicine. When administering a treatment, one should consider individual patient characteristics, comorbidities and, what is most important, the prevailing symptoms, as well as the clinical phenotype of a disease. This is directly related to chronic musculoskeletal pain (MSP), which occurs with underlying most prevalent joint and vertebral disorders. At present, MSP is considered to be an independent clinical syndrome.Predominant mechanisms of MSP pathophysiology allow for determination of its special phenotypes: “inflammatory”, “mechanical”, related to enthesopathy and central sensitization. Treatment strategies for MSP phenotypes should obviously be differentiated and based on a tailored and pathophysiologically sound of medical agents and non-medical measures with different mechanisms of pharmacological effects. Effective treatment of the “inflammatory” phenotype requires the use of non-steroidal anti-inflammatory drugs, topical glucocorticoids, disease modifying anti-inflammatory agents. The “mechanical” phenotype necessitates the correction of biomechanical abnormalities, the use of hyaluronic acid containing agents, whereas the “enthesopathic” phenotype is treated with local therapy. Treatment of the phenotype with central sensitization is performed with agents effective for neuropathic pain (anticonvulsants, anti-depressants).

The important role of central sensitization in chronic musculoskeletal pain seen in different rheumatic diseases

OBJECTIVE

This study explored the role of central sensitization (CS) pain in patients with various rheumatic diseases using the CS inventory (CSI).

METHODS

A total of 193 patients of mean age 50.72 ± 9.65 years were included; they were divided into four different groups in terms of their rheumatic diseases. Patients with rheumatoid arthritis (RA), spondyloarthropathy (SpA), osteoarthritis (OA), and fibromyalgia syndrome (FMS) were evaluated in tertiary care rheumatology/pain medicine settings. Disease duration and activity, the Bath Ankylosing Spondylitis Disease Activity Index, the Disease Activity Score-28, and pain severity (evaluated using a visual analog scale) were assessed, and the Turkish version of the CSI administered.

RESULTS

CS syndromes were present in almost half the patients (45% of SpA, 41% of RA, 62% of OA, and 94% of FMS patients). We found no significant relationship between disease activity and the CSI-A scores in SpA or RA patients (p = 0.731 and p = 0.390, respectively). As expected, the CSI-A scores were highest in the FMS group (p = 0.000), but were similar in the other groups (p < 0.05). CS-related syndromes (CSI-B conditions) were present at similar frequencies in the RA, SpA, and OA groups, but were less common in the FMS group (p = 0.000).

CONCLUSIONS

The CSI usefully detects CS pain in patients with rheumatic diseases. Treatment of such pain can enhance the quality of daily life in patients with rheumatic diseases.Key Point• Central sensitization pain is common in patients with rheumatic diseases including rheumatoid arthritis, spondyloarthropathies, and osteoarthritis.

Efficacy and safety of cannabidiol followed by an open label add-on of tetrahydrocannabinol for the treatment of chronic pain in patients with rheumatoid arthritis or ankylosing spondylitis: protocol for a multicentre, randomised, placebo-controlled study

INTRODUCTION

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are chronic, systemic, inflammatory diseases, primarily in the musculoskeletal system. Pain and fatigue are key symptoms of RA and AS. Treatment presents a clinical challenge for several reasons, including the progressive nature of the diseases and the involvement of multiple pain mechanisms. Moreover, side effects of pain treatment pose an implicit risk. Currently, no well-controlled studies have investigated how medical cannabis affects pain and cognitive functions in RA and AS. The present study aims to evaluate the efficacy and safety of medical cannabis in the treatment of persistent pain in patients with RA and AS with low disease activity.

METHODS AND ANALYSIS

A double-blinded, randomised, placebo-controlled study of cannabidiol (CBD), followed by an open label add-on of tetrahydrocannabinol (THC) with collection of clinical data and biological materials in RA and AS patients treated in routine care. The oral treatment with CBD in the experimental group is compared with placebo in a control group for 12 weeks, followed by an observational 12-week period with an open label add-on of THC in the primary CBD non-responders. Disease characteristics, psychological parameters, demographics, comorbidities, lifestyle factors, blood samples and serious adverse events are collected at baseline, after 12 and 24 weeks of treatment, and at a follow-up visit at 36 weeks. Data will be analysed in accordance with a predefined statistical analysis plan.

ETHICS AND DISSEMINATION

The Danish Ethics Committee (S-20170217), the Danish Medicines Agency (S-2018010018) and the Danish Data Protection Agency approved the protocol. The project is registered in the European Clinical Trials Database (EudraCT 2017-004226-15). All participants will give written informed consent to participate prior to any study-related procedures. The results will be presented at international conferences and published in peer-reviewed journals.

Improving Scoring Precision and Internal Construct Validity of the Bath Ankylosing Spondylitis Disease Activity Index Using Rasch Measurement Theory

OBJECTIVE

To test the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) according to Rasch Measurement Theory and investigate whether measurement precision can be improved.

METHODS

Secondary analysis of a BASDAI database. The data had been collected from individuals starting an Ankylosing Spondylitis Exercise Course at the Royal National Hospital for Rheumatic Diseases in Bath, UK.

RESULTS

Data were available for 250 participants (23.6% female) aged between 18 and 85 years (mean 52.8, SD 14.6). Initial fit of the data to the Rasch model appeared good and item thresholds were consistent, but local item dependence (LID) was identified. After addressing the LID, a unidimensional measure was achieved. The Person Separation Index (reliability) was 0.83 and the location of the items was well matched to that of the respondents. A transformation table was generated to convert total raw BASDAI scores into linearized Rasch transformed scores that form an interval scale. The Smallest Detectable Difference improved from 2 to 1.2. This finding suggests that a change score of > 1.2 points on the modified BASDAI is required to achieve meaningful change.

CONCLUSION

Applying the Rasch transformed scores simplifies completion and scoring of the measure and confirms internal construct validity. It also ensures linear measurement and justifies the use of parametric statistical analyses when analyzing datasets. The transformation table can be used with existing BASDAI datasets to allow direct comparisons of disease activity scores with those generated from future studies.

Pain and affective distress in arthritis: relationship to immunity and inflammation

INTRODUCTION

Most arthritides are associated with pain and psychological distress (clinically significant depression and anxiety). Pain and depression are mutually exacerbating; both may continue even when joint involvement appears well controlled. Area covered: There is strong evidence that arthritis-related stress impacts the central nervous system and, together with peripheral inflammatory changes, can cause central sensitization that can lead to chronic pain and worsening of affective distress. Cytokines and chemokines participate both in joint inflammation and in central sensitization. We review evidence of these relationships in five arthritides, namely rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, gout, and in osteoarthritis of the hips and knees. Central sensitization in these conditions results in long-lasting pain and psychological distress. Expert commentary: Chronic pain and depression are important but often neglected in the clinical assessment and treatment of arthritis. The potential role of biologic cytokines and Janus kinase inhibitors in dealing with these symptoms needs further study.

Opioid Use in Patients with Ankylosing Spondylitis Is Common in the United States: Outcomes of a Retrospective Cohort Study

OBJECTIVE

To assess the prevalence of chronic opioid use in patients with ankylosing spondylitis (AS), and to compare the characteristics of patients with and without chronic opioid use.

METHODS

This was a retrospective cohort study of patients with AS identified in the Truven Health MarketScan Research database between January 1, 2012, and March 31, 2017. Commercial and Medicaid claims data were examined using both specific (720.0 and M45.x) and broader (720.x and M45.x) International Classification of Diseases (ICD) coding definitions. Patients were aged ≥ 18 years on the date of first qualifying ICD code occurrence (the index date). Demographics and clinical characteristics were assessed in the 12-month period preceding the index date. The 12-month followup period was used to assess prevalence and characteristics of chronic opioid use.

RESULTS

Chronic opioid use was common among patients with commercial claims (23.5% of ICD 720.0 patients; 27.3% of ICD 720.x patients), and especially those with Medicaid claims (57.1% and 76.7%, respectively). The proportion of patients with claims for anti-tumor necrosis factor therapies during followup was often low, and for Medicaid patients was lower among those with chronic opioid use (29.6% of ICD 720.0 patients; 2.3% of ICD 720.x patients) than those without (47.1% and 7.1%, respectively). Among chronic opioid users in all cohorts, the cumulative supply of opioids was typically high (≥ 270 days in the followup period); most opioids prescribed were Schedule II.

CONCLUSION

Patients with AS receive opioids with disturbing frequency. The infrequent prescription of recommended therapies to these patients reflects a need to optimize treatment further through education of patients and healthcare professionals alike.

Abnormal Low-Frequency Oscillations Reflect Trait-Like Pain Ratings in Chronic Pain Patients Revealed through a Machine Learning Approach

Measures of moment-to-moment fluctuations in brain activity of an individual at rest have been shown to be a sensitive and reliable metric for studying pathological brain mechanisms across various chronic pain patient populations. However, the relationship between pathological brain activity and clinical symptoms are not well defined. Therefore, we used regional BOLD signal variability/amplitude of low-frequency oscillations (LFOs) to identify functional brain abnormalities in the dynamic pain connectome in chronic pain patients that are related to chronic pain characteristics (i.e., pain intensity). Moreover, we examined whether there were sex-specific attributes of these functional brain abnormalities and whether functional brain abnormalities in patients is related to pain intensity characteristics on different time scales. We acquired resting-state functional MRI and quantified frequency-specific regional LFOs in chronic pain patients with ankylosing spondylitis. We found that patients exhibit frequency-specific aberrations in LFOs. Specifically, lower-frequency (slow-5) abnormalities were restricted to the ascending pain pathway (thalamus and S1), whereas higher-frequency abnormalities also included the default mode (i.e., posterior cingulate cortex; slow-3, slow-4) and salience (i.e., mid-cingulate cortex) networks (slow-4). Using a machine learning approach, we found that these abnormalities, in particular within higher frequencies (slow-3), can be used to make generalizable inferences about patients' average pain ratings (trait-like pain) but not current (i.e., state-like) pain levels. Furthermore, we identified sex differences in LFOs in patients that were not present in healthy controls. These novel findings reveal mechanistic brain abnormalities underlying the longer-lasting symptoms (trait pain intensity) in chronic pain.SIGNIFICANCE STATEMENT Measures of moment-to-moment fluctuations in brain activity of an individual at rest have been shown to be a reliable metric for studying functional brain associated with chronic pain. The current results demonstrate that dysfunction in these intrinsic fluctuations/oscillations in the ascending pain pathway, default mode network, and salience network during resting state display sex differences and can be used to make inferences about trait-like pain intensity ratings in chronic pain patients. These results provide robust and generalizable implications for investigating brain mechanisms associated with longer-lasting/trait-like chronic pain symptoms.

Association of neuropathic-like pain characteristics with clinical and radiographic features in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, progressive, and inflammatory disorder and causes chronic back pain. It is not unusual for patients with AS to have symptoms similar to neuropathic pain. We aimed to investigate the neuropathic pain (NeP) component in patients with AS using the painDETECT questionnaire (PD-Q) and to assess the relation between NeP and the disease characteristics of AS. A single-center prospective study was performed, including 105 patients. Patients with AS completed three questionnaires: PD-Q, Beck Depression Inventory (BDI), and Euro Quality of Life (EQ-5D) questionnaires. Patients were classified into three groups according to the PD-Q scores: nociceptive pain (NoP) (score ≤ 12), mixed pain (MP) (score 13-18), and NeP pain (score ≥ 19). Fifteen patients (14.2%) were classified into the NeP group, 22 (21.0%) in the MP group, and 68 (64.8%) in the NoP group. The questionnaires and clinical and radiographic findings were analyzed. Patients with NeP and MP scored worse on the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI); BDI; modified Stoke Ankylosing Spondylitis Spine Score; pain-visual analog scale (VAS); and EQ-5L index and showed an increased prevalence of enthesitis and peripheral arthritis. There were no differences in objective inflammatory markers. PD-Q scores were positively correlated with pain-VAS, BASDAI, BDI, and inversely correlated with EQ-5D index. Age, BASDAI, presence of current enthesitis, and BDI score were independently associated with PD-Q scores. The findings showed that NeP component in AS was associated with age, high disease activity, presence of current enthesitis, and depression.

Role of inflammasomes in inflammatory autoimmune rheumatic diseases

Inflammasomes are intracellular multiprotein complexes that coordinate anti-pathogenic host defense during inflammatory responses in myeloid cells, especially macrophages. Inflammasome activation leads to activation of caspase-1, resulting in the induction of pyroptosis and the secretion of pro-inflammatory cytokines including interleukin (IL)-1β and IL-18. Although the inflammatory response is an innate host defense mechanism, chronic inflammation is the main cause of rheumatic diseases, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), ankylosing spondylitis (AS), and Sjögren's syndrome (SS). Since rheumatic diseases are inflammatory/autoimmune disorders, it is reasonable to hypothesize that inflammasomes activated during the inflammatory response play a pivotal role in development and progression of these diseases. Indeed, previous studies have provided important observations that inflammasomes are actively involved in the pathogenesis of inflammatory/autoimmune rheumatic diseases. In this review, we summarize the current knowledge on several types of inflammasomes during macrophage-mediated inflammatory responses and discuss recent research regarding the role of inflammasomes in the pathogenesis of inflammatory/autoimmune rheumatic diseases. This avenue of research could provide new insights for the development of promising therapeutics to treat inflammatory/autoimmune rheumatic diseases.

Chiropractic Care in the Management of Inactive Ankylosing Spondylitis: A Case Series

Objective

This report describes chiropractic management for 3 cases of inactive ankylosing spondylitis (AS).

Clinical Features

A 25-year-old woman presented with chronic, mechanical neck pain and stiffness that was ultimately diagnosed as AS. A 23-year-old man presented with chronic low back and left hip pain that was diagnosed as AS. A 31-year-old man with low back pain presented with a known diagnosis of AS. Physical examination in 2 cases failed to identify systemic findings associated with AS. In the third case, examination revealed a history of ulcerative colitis. Laboratory examination of case 2 yielded a positive HLA-B27, but cases 1 and 3 were HLA-B27 negative. The acute reactants were negative in all 3 patients, indicating an inactive phase of disease. All 3 patients underwent spinal imaging including sacroiliac joint radiography. In case 3, magnetic resonance imaging of the sacroiliac joints was performed. All 3 imaging examinations revealed bilateral, symmetric sacroiliitis.

Interventions and Outcome

Patients were managed by both a medical rheumatologist and a doctor of chiropractic. Chiropractic care ranged from instrument-assisted spinal manipulation to diversified spinal and soft tissue manipulation and Cox flexion-distraction. Patients were given home stretches and rehabilitation exercises. All 3 patients experienced some relief of their symptoms including pain reduction and improved activities of daily living.

Conclusion

These 3 patients displayed differences and commonalities in clinical, laboratory, and imaging features. Chiropractic manipulation and rehabilitation seemed to be beneficial in reducing symptomatology and improving musculoskeletal function for these 3 patients. These findings suggest the potential for collaborative or integrative management in similar cases.