The course of pain hypersensitivity according to painDETECT in patients with rheumatoid arthritis initiating treatment: results from the prospective FRAME-cohort study

Predictors for severe persisting pain in rheumatoid arthritis are associated with pain origin and appraisal of pain

OBJECTIVES

To determine the proportion of patients with rheumatoid arthritis (RA) with severe persisting pain and to identify predictive factors despite treatment-controlled disease activity.

METHODS

This prospective multicentre study included outpatients with RA scheduled for escalation of anti-inflammatory treatment due to active disease and severe pain (Disease Activity Score 28 (DAS28)>3.2 and Visual Analogue Scale (VAS)>50). At week 24, patients were stratified into reference group (DAS28 improvement>1.2 or DAS28≤3.2 and VAS pain score<50), non-responders (DAS28 improvement≤1.2 and DAS28>3.2, regardless of VAS pain score) and persisting pain group (DAS28 improvement>1.2 or DAS28≤3.2 and VAS pain score≥50). The former two subgroups ended the study at week 24. The latter continued until week 48. Demographic data, DAS28-C reactive protein, VAS for pain, painDETECT Questionnaire (PD-Q) to identify neuropathic pain (NeP) and the Pain Catastrophising Scale were assessed and tested for relation to persisting pain.

RESULTS

Of 567 patients, 337 (59.4%) were classified as reference group, 102 (18.0%) as non-responders and 128 (22.6%) as patients with persisting pain. 21 (8.8%) responders, 28 (35.0%) non-responders and 27 (26.5%) persisting pain patients tested positive for NeP at week 24. Pain catastrophising (p=0.002) and number of tender joints (p=0.004) were positively associated with persisting pain at week 24. Baseline PD-Q was not related to subsequent persisting pain.

CONCLUSIONS

Persisting and non-nociceptive pain occur frequently in RA. Besides the potential involvement of NeP, pain catastrophising and a higher number of tender joints coincide with persisting pain.

Comparative analysis of centrally mediated and inflammatory pain experiences amongst patients diagnosed with rheumatoid arthritis: A multimethods study

BACKGROUND

The identification of pain originating from distinct biological processes may lead to individualised pain treatment. In this study, we aimed to explore the pain experiences of patients with rheumatoid arthritis (RA), differentiating between those predominantly exhibiting features of peripheral inflammatory versus centrally mediated pain.

METHODS

Through a multimethods approach we (i) quantitatively analysed the differences in pain descriptors between patients diagnosed with RA experiencing peripheral inflammatory and centrally mediated pain, utilising the Short Form-McGill Pain Questionnaire which includes the pain visual analogue scale (VAS) and (ii) qualitatively explored their subjective pain experiences grounded in the biopsychosocial model, commonly applied in chronic pain.

RESULTS

Participants with centrally mediated pain reported higher pain scores on the VAS, used a wider range of pain descriptors, and a higher proportion selected each descriptor compared to those with inflammatory pain (p < .001). The qualitative analysis revealed the centrally mediated pain group's experiences were overwhelming and relentless, struggling to precisely articulate the nature of their pain. In contrast, individuals with inflammatory pain expressed their pain in more tangible terms and shared their adaptive and coping strategies. Importantly, both groups revealed the substantial psychological, functional and social impacts of their pain, highlighting the often 'invisible' and misunderstood nature of their symptoms.

CONCLUSION

This study has gained a deeper insight into the pain experiences of patients living with RA, particularly in differentiating between centrally mediated and inflammatory types of pain, potentially facilitating a more individualised approach to pain treatment.

PATIENT CONTRIBUTION

Patients actively participated in the study conception and design. This engagement includes collaboration with key stakeholders, such as members of the National Rheumatoid Arthritis Society and Patient Research Partners (PRPs), who provided continuous feedback and guidance throughout the research process. Specifically, the qualitative element was coproduced with two PRPs, who were involved in co-leading the focus groups and data analysis.

Exploring the complexities of pain phenotypes: OMERACT 2023 chronic pain working group workshop

OBJECTIVE

To educate and discuss pain mechanisms (nociceptive, neuropathic, nociplastic) illuminating its possible impact when measuring different outcomes, which may modify, confound and potentially bias the outcome measures applied across various aspects of Rheumatic Musculoskeletal Diseases (RMDs) clinical trials.

METHODS

In the plenary presentations, PM lectured on different pain mechanisms and impact on disease activity assessment. Data from two data sets of RMDs patients, which assessed the prevalence and impact of nociplastic pain were presented and reviewed. Audience breakout group sessions and polling were conducted.

RESULTS

Mixed pain etiologies may differentially influence disease activity assessment and therapeutic decision-making. Polling demonstrated a consensus on the need to assess different types of pain as a phenotype, as it constitutes an important contextual factor (a variable that is not an outcome of the trial, but needs to be recognized [and measured] to understand the study results), and to standardize across RMDs.

CONCLUSION

There is need for a standardized pain measure that can differentiate underlying pain mechanisms.

A systematic review and meta-analysis of questionnaires to screen for pain sensitisation and neuropathic like pain in inflammatory arthritis

BACKGROUND

Targeted pain relief is a major unmet medical need for patients with inflammatory arthritis (IA), where approximately 40% of patients experience persistent pain. Self-reported questionnaires which report on pain sensitivity and neuropathic like pain may provide an insight into certain pain types to guide targeted treatment.

OBJECTIVE

In this systematic review and meta-analysis we evaluated self-reported pain sensitivity and neuropathic like pain in subjects with IA, as defined by questionnaires.

METHODS

MEDLINE, Embase, Web of Science, PsycINFO and google scholar were searched for publications and conference abstracts, reporting on pain sensitivity and neuropathic pain using painDETECT, DN4, LANSS, CSI, PSQ and McGill pain questionnaire in adult patients with IA. Risk of bias was assessed using National Institute of Health Quality Assessment Tool. Meta-analysis according to individual questionnaire criteria, was undertaken.

RESULTS

63 studies (38 full text and 25 conference abstracts) were included in the review, reporting on a total of 13,035 patients. On meta-analysis, prevalence of pain sensitivity/neuropathic like pain in IA was 36% (95% CI 31-41%) according to painDETECT, 31% (95% CI 26-37%) according to the DN4, 40% (95% CI 32-49%) according to the LANSS and 42% (95% CI 34-51%) according to the CSI. On meta-regression, prevalence of pain sensitivity/neuropathic pain in RA was significantly lower than SpA (p = 0.01) and PsA (p = 0.002) using the painDETECT questionnaire. Across all questionnaires, pain sensitivity and neuropathic like pain were significantly associated with worse pain severity, disease activity, disability, quality of life and anxiety and depression measures. Studies reporting on whether neuropathic like pain is a predictor of treatment outcome were inconsistent.

CONCLUSION

Pain sensitivity and neuropathic like pain contribute to pain perception in up to 42% of patients with IA. Despite substantial heterogeneity between studies on meta-analysis, this review highlights the large proportion of patients with IA who may experience pain due to underlying mechanisms other than, or in addition to, synovial inflammation.

Non-inflammatory pain in inflammatory arthritis

'Non-inflammatory' pain, pain that is not associated with measures of inflammation, is common in patients with inflammatory arthritis including RA. One important cause of non-inflammatory pain is concomitant fibromyalgia. Systematic review has shown that fibromyalgia is common in inflammatory arthritis including RA affecting 1 in 5 patients and is associated with higher disease activity scores due to inflated tender joint count and patient global assessment. Consequently, many patients with RA and concomitant fibromyalgia may fail to reach treatment target and switch to alternate disease modifying drugs frequently. European Alliance of Association for Rheumatology has highlighted that concomitant fibromyalgia is an important consideration in assessing difficult-to-treat RA. The incidence and prevalence of fibromyalgia are higher in RA than the general population, raising the possibility that fibromyalgia may be 'secondary' to RA rather than a concomitant disease. The precise mechanisms whereby patients with RA develop fibromyalgia are unknown. In this review, we discussed fibromyalgia in RA, its clinical impact and epidemiology as well as data suggesting fibromyalgia might be 'secondary'. Lastly, we reviewed potential pathogenic mechanisms which included inflammatory cytokines sensitizing nociceptive neurones, temporal summation, also known as windup, from chronic pain and impaired coping from poor quality sleep and mental well-being. Deciphering the exact mechanisms may lead to treatment strategies that prevent development of secondary fibromyalgia and will address a common factor associated with difficult-to-treat RA.

The Definition, Assessment, and Prevalence of (Human Assumed) Central Sensitisation in Patients with Chronic Low Back Pain: A Systematic Review

Central sensitisation is assumed to be one of the underlying mechanisms for chronic low back pain. Because central sensitisation is not directly assessable in humans, the term 'human assumed central sensitisation' (HACS) is suggested. The objectives were to investigate what definitions for HACS have been used, to evaluate the methods to assess HACS, to assess the validity of those methods, and to estimate the prevalence of HACS. Database search resulted in 34 included studies. Forty different definition references were used to define HACS. This review uncovered twenty quantitative methods to assess HACS, including four questionnaires and sixteen quantitative sensory testing measures. The prevalence of HACS in patients with chronic low back pain was estimated in three studies. The current systematic review highlights that multiple definitions, assessment methods, and prevalence estimates are stated in the literature regarding HACS in patients with chronic low back pain. Most of the assessment methods of HACS are not validated but have been tested for reliability and repeatability. Given the lack of a gold standard to assess HACS, an initial grading system is proposed to standardize clinical and research assessments of HACS in patients with a chronic low back.

Why It Hurts: The Mechanisms of Pain in Rheumatoid Arthritis

Pain is a near-universal feature of rheumatoid arthritis, but peripheral joint inflammation may not suffice to explain the etiology of pain in all patients with rheumatoid arthritis. Inflammation in rheumatoid arthritis releases several algogens that may generate pain. Also, central nervous system processes may play a crucial role in the regulation and perpetuation of pain. Several methods for assessing pain in rheumatoid arthritis exist, and recently the role of assessing therapeutics in treating specific etiologies of pain has gained interest.

Effects of Chaihu-Shugan-San capsule for psychogenic erectile dysfunction: Study protocol of a randomized placebo-controlled trial

BACKGROUND

Erectile dysfunction (ED) affects many adult men worldwide. Many studies on the brain of psychogenic ED have shown significant cerebral functional changes and reduced volume of gray matter and white matter microstructural alterations in widespread brain regions. Chaihu-Shugan-San (CHSGS) capsule has been used to treat ED from the 20th century in China. However, clinical research of CHSGS capsule in the treatment of ED was lack. We design this study to evaluate the efficacy and safety of CHSGS capsule in the treatment of patients suffering from psychogenic ED. Furthermore, we also aim to provide a new evidence as well as an innovation of the clinical treatment in psychogenic ED.

METHODS

This study is designed as a multi-center, 3-arms, randomized trial. From the perspective of psychogenic ED, we will divide patients into 3 groups, which are placebo group, tadalafil group and CHSGS group. One hundred thirty-five patients will be randomly allocated to receive placebo, CHSGS capsule or tadalafil oral pharmacotherapy. After the period of 4-week treatment, the outcome of primary assessment changes in the brain MRI, IIEF-5, EHS, and QEQ total scores from baseline. Secondary assessments include the SEAR, HAMA-14, HAMD-17 scores, response rate of the patients and their partners.

DISCUSSION

We designed this study based on previous research about psychogenic erectile dysfunction (ED). This study will provide objective evidences to evaluate the effects of CHSGS capsule as an adjuvant treatment for psychogenic ED.

TRIAL REGISTRATION NUMBER

chictr.org.cn, ChiCTR-IOR-1800018301.

The Effect of Neuropathic Pain Symptoms on Remission in Patients with Early Rheumatoid Arthritis

BACKGROUND

The presence of neuropatic pain (NeP) is common in subjects with established Rheumatoid Arthritis (RA), and it can influence the disease remission. These aspects have not been investigated in patients with Early Rheumatoid Arthritis (ERA).

OBJECTIVE

To investigate the effect of NeP on the achievement of remission in patients with ERA.

METHOD

The study involved consecutive ERA patients with moderate or high disease activity. The painDETECT Questionnaire (PDQ), the 36-item Short Form Health Survey (SF-36), and the Euro- QoL-5 Dimensions (EQ-5D) were administered to all the patients, and their co-morbidity data were used to calculate their modified Rheumatic Disease Comorbidity Index (mRDCI). After six months' follow-up, the presence or otherwise of NeP in each individual patient was calculated, and whether or not the Boolean remission criteria were satisfied.

RESULTS

The study was completed by 115 patients (76% females) whose PDQ scores indicated that 13% had probable NeP. At the end of the follow-up period, 25 patients (21.7%) met the Boolean remission criteria. Logistic regression analysis showed that baseline PDQ scores (p=0.0023) and the mRDCI (p=0.0054) were the strongest predictors of not being in Boolean remission. Only one of the 15 patients with concomitant NeP achieved Boolean remission.

CONCLUSION

The presence of NeP may affect the achievement of remission in ERA patients. The PDQ can be a useful tool to measure central pain sensitisation in such patients.

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.

New concepts of pain

Active research is being conducted on musculoskeletal pain, and recent concepts will help clinicians and researchers to develop better approaches: -the new pain taxonomy recently has been modified with a third descriptor with the concept of nociplastic pain. -the latest International Classification of Diseases (ICD-11) includes an IASP task force that developed a new classification system for pain. In this new classification, one can differentiate primary musculoskeletal pain including fibromyalgia and low back pain and secondary musculoskeletal pain related to specific etiologies. -the concept of central sensitization in inflammatory rheumatic diseases is increasingly discussed. In these conditions, even with very active biological treatment, almost a third of patients are still complaining of persisting pain. These persisting pain states under adequate treatment, without any sign of inflammation, led researchers to look for evidence of central sensitization states.