Is Swollen to Tender Joint Count Ratio a New and Useful Clinical Marker for Biologic Drug Response in Rheumatoid Arthritis? Results From a Swedish Cohort

Having More Tender Than Swollen Joints Is Associated With Worse Patient-Reported Outcomes in Patients With Early RA

BACKGROUND/OBJECTIVE

In patients with rheumatoid arthritis (RA), high tender-swollen joint differences (TSJDs) have been associated with worse outcomes. A better understanding of the phenotype and impact of high TSJD on patient-reported outcomes (PROs) in early RA may lead to earlier personalized treatment targeting domains that are important to patients today. Our objectives were to evaluate the impact of TSJD on updated PROs in patients with early RA over 1 year and to determine differences in associations by joint size.

METHODS

This longitudinal cohort study followed patients with active, early RA enrolled in the Canadian Early Arthritis Cohort between 2016 and 2022, who completed clinical assessments and PROMIS-29 measures over 1 year. Twenty-eight joint counts were performed and TSJDs calculated. Adjusted associations between TSJD and PROMIS-29 scores were estimated using separate linear-mixed models. Separate analyses of large versus small-joint TJSDs were performed.

RESULTS

Patients with early RA (n = 547; 70% female; mean [SD] age, 56 [15] years; mean [SD] symptom duration, 5.3 [2.9] months) were evaluated. A 1-point increase in TSJD was significantly associated with worse PROMIS T-scores in all domains: physical function (adjusted regression coefficient, -0.27; 95% confidence interval [CI], -0.39, -0.15), social participation (adjusted regression coefficient, -0.34; 95% CI, -0.50, -0.19), pain interference (adjusted regression coefficient, 0.49; 95% CI, 0.35, 0.64), sleep problems (adjusted regression coefficient, 0.29; 95% CI, 0.16, 0.43), fatigue (adjusted regression coefficient, 0.34; 95% CI, 0.18, 0.50), anxiety (adjusted regression coefficient, 0.23; 95% CI, 0.08, 0.38), and depression (adjusted regression coefficient, 0.20; 95% CI, 0.06, 0.35). Large-joint TSJD was associated with markedly worse PROs compared with small-joint TSJD.

CONCLUSIONS

Elevated TSJD is associated with worse PROs particularly pain interference, social participation, and fatigue. Patients with more tender than swollen joints, especially large joints, may benefit from earlier, targeted therapeutic interventions.

"Inflammatory or non-inflammatory pain in inflammatory arthritis - How to differentiate it?"

Pain is a significant issue in rheumatoid arthritis (RA) and psoriatic arthritis (PSA) and can have a negative impact on patients' quality of life. Despite optimal control of inflammatory disease, residual chronic pain remains a major unmet medical need in RA. Pain in RA can be secondary to inflammation but can also generate neuroendocrine responses that initiate neurogenic inflammation and enhance cytokine release, leading to persistent hyperalgesia. In addition to well-known cytokines such as TNFα and IL-6, other cytokines and the JAK-STAT pathway play a role in pain modulation and inflammation. The development of chronic pain in RA involves processes beyond inflammation or structural damage. Residual pain is often observed in patients even after achieving remission or low disease activity, suggesting the involvement of non-inflammatory and central sensitization mechanisms. Moreover, fibromyalgia syndrome (FMS) is prevalent in RA patients and may contribute to persistent pain. Factors such as depression, sleep disturbance, and pro-inflammatory cytokines may contribute to the development of fibromyalgia in RA. It is essential to identify and diagnose concomitant FMS in RA patients to better manage their symptoms. Further research is needed to unravel the complexities of pain in RA. Finally, recent studies have shown that JAK inhibitors effectively reduce residual pain in RA patients, suggesting pain-reducing effects independent of their anti-inflammatory properties.

Towards Personalized Medicine in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, incurable, multisystem, inflammatory disease characterized by synovitis and extra-articular features. Although several advanced therapies targeting inflammatory mechanisms underlying the disease are available, no advanced therapy is universally effective. Therefore, a ceiling of treatment response is currently accepted where no advanced therapy is superior to another. The current challenge for medical research is the discovery and integration of predictive markers of drug response that can be used to personalize medicine so that the patient is started on "the right drug at the right time". This review article summarizes our current understanding of predicting response to anti-rheumatic drugs in RA, obstacles impeding the development of personalized medicine approaches and future research priorities to overcome these barriers.

Identifying and Managing Nociplastic Pain in Individuals With Rheumatic Diseases: A Narrative Review

Chronic pain is a burdensome and prevalent symptom in individuals with rheumatic disease. The International Association for the Study of Pain classifies pain into 3 descriptive categories: nociceptive, neuropathic, and nociplastic. These categories are intended to provide information about the mechanisms underlying the pain, which can then serve as targets for drug or non-drug treatments. This review describes the 3 types of pain as they relate to patients seen by rheumatology health care providers. The focus is on identifying individuals with nociplastic pain, which can either occur in isolation as in fibromyalgia, or as a comorbidity in individuals with primary autoimmune conditions, such as rheumatoid arthritis and systemic lupus erythematosus. Practical information about how rheumatology health care providers can approach and manage chronic pain is also provided.

Joint-level responses to tofacitinib and methotrexate: a post hoc analysis of data from ORAL Start

BACKGROUND

Rheumatoid arthritis (RA) has a variable impact on different synovial joints, with inflammation being more commonly observed in some joints than others. Emerging evidence suggests that the anatomical variation in pathophysiology could result in differential responses to treatments across the joints, both within and between modes of action. This analysis aimed to characterize joint-specific responses to tofacitinib and methotrexate monotherapy in patients with RA.

METHODS

This was a post hoc analysis of data from the phase III trial ORAL Start (NCT01039688), in methotrexate-naïve patients with RA. A paired joint pathology score (PJPS), derived from bilateral tender/swollen joint counts, was calculated. The percentage change from baseline in PJPS (%∆PJPS) and treatment-specific responses (tofacitinib 5 and 10 mg twice daily [BID] vs methotrexate; tofacitinib 5 vs 10 mg BID) for each patient joint pair, except for those with baseline/post-baseline PJPS = 0, were calculated at month 3, month 6, and month 12. Radiographic progression was similarly assessed using the Modified Total Sharp Score at month 6 and month 12.

RESULTS

In methotrexate-naïve patients, differences in %∆PJPS demonstrated greater responses with tofacitinib vs methotrexate in most joint locations. Lesser responses with tofacitinib vs methotrexate were observed in most joints of the feet, particularly at month 12. Despite this, radiographic progression at month 12 was significantly worse in the foot (and metacarpophalangeal) joints of patients receiving methotrexate vs tofacitinib.

CONCLUSION

We observed variation in joint-specific responses with tofacitinib and methotrexate monotherapy. Despite a proximal-distal efficacy gradient, with better clinical responses in the feet, patients receiving methotrexate monotherapy demonstrated more radiographic progression in the foot joints compared with those receiving tofacitinib. These findings suggest that body site- and therapy-specific characteristics may interact to produce differential treatment responses.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01039688.

Further evaluation of inflammatory and non-inflammatory aspects of pain in rheumatoid arthritis patients

Objective

A high discrepancy between the number of tender and swollen joints (e.g. ΔTSJ ≥ 7) has previously been used as an indication for the presence of changes in central mechanisms in patients with moderate-to-high disease activity. In this study, we explored whether the ΔTSJ can also be used to obtain insights into the underlying pain mechanisms in patients with on average well-controlled disease activity.

Methods

A 2 year retrospective analysis of routinely obtained 28-joint DAS (DAS28) components was performed on 45 patients with low inflammatory activity at the group level. All patients underwent pressure pain threshold (PPT) and electrical pain threshold (EPT) measurements and completed four self-report questionnaires [short-form 36 (SF-36v2); central sensitization inventory (CSI); generalized pain questionnaire (GPQ); and the pain catastrophizing scale (PCS)].

Results

Patients with a ΔTSJ ≥ 3 at least once in the past 2 years showed significantly lower EPT and PPT values and higher levels of pain and disability on the SF-36v2 compared with the ΔTSJ < 3 group. Furthermore, GPQ scores were significantly higher in those with ΔTSJ ≥ 3, while CSI and PCS scores were similar.

Conclusion

These findings suggest that in patients in the ΔTSJ ≥ 3 group, mechanisms other than inflammation (only) underlie the pain. Moreover, our findings suggest that among the multiple potential underlying psychological mechanisms, pain catastrophizing (as measured by the PCS) and psychological hypervigilance (as measured by the CSI) do not play an important role. These findings could be useful in the clinical management of the patient. Depending on the dominant mechanism underlying the (persistent) pain, patients might respond differently to treatment.

Disproportionate articular pain is a frequent phenomenon in rheumatoid arthritis and responds to treatment with sarilumab

OBJECTIVES

In some patients with RA, joint pain is more severe than expected based on the amount of joint swelling [referred to as disproportionate articular pain (DP)]. We assessed DP prevalence and the effects of sarilumab, an IL-6 inhibitor, on DP.

METHODS

Data from RA patients treated with placebo or 200 mg sarilumab in the phase 3 randomized controlled trials (RCTs) MOBILITY and TARGET, adalimumab 40 mg or sarilumab 200 mg in the phase 3 RCT MONARCH and sarilumab 200 mg in open-label extensions (OLEs) were used. DP was defined as an excess tender 28-joint count (TJC28) over swollen 28-joint count (SJC28) of ≥7 (TJC28 - SJC28 ≥ 7). Treatment response and disease activity were determined for patients with and without DP.

RESULTS

Of 1531 sarilumab 200 mg patients from RCTs, 353 (23%) had baseline DP. On average, patients with DP had higher 28-joint DAS using CRP (DAS28-CRP) and pain scores than patients without DP, whereas CRP levels were similar. After 12 and 24 weeks, patients with baseline DP treated with sarilumab were more likely to be DP-free than those treated with placebo or adalimumab. In RCTs, more sarilumab-treated patients achieved low disease activity vs comparators, regardless of baseline DP status. In OLEs, patients were more likely to lose rather than gain DP status.

CONCLUSION

About one-quarter of patients with RA experienced DP, which responded well to sarilumab. These data support the concept that other mechanisms (potentially mediated via IL-6) in addition to inflammation may contribute to DP in RA.

TRIAL REGISTRATIONS

NCT01061736, NCT02332590, NCT01709578, NCT01146652.

Evaluation of Clinical Diagnosis of Axial Psoriatic Arthritis or Elevated Patient-Reported Spine Pain in CorEvitas' Psoriatic Arthritis/Spondyloarthritis Registry

OBJECTIVE

To determine the presence of axial symptoms in patients with psoriatic arthritis (PsA) and examine differences between those with or without a diagnosis of axial PsA (axPsA).

METHODS

Patients with PsA at their CorEvitas' (formerly Corrona) Psoriatic Arthritis/Spondyloarthritis Registry enrollment visit were stratified into 4 mutually exclusive groups based on axial manifestations: physician-diagnosed axPsA only (Dx⁺Sx^-), patient-reported elevated spine symptoms only (Dx^-Sx⁺; defined as Bath Ankylosing Spondylitis Disease Activity Index ≥4 and spine pain visual analog scale ≥40), physician-diagnosed and patient-reported (Dx⁺Sx⁺), and no axial manifestations (Dx^-Sx^-). Patient characteristics, disease activity, and patient-reported outcomes (PROs) at enrollment in each axial manifestation group were compared with the Dx^-Sx^- group. Associations of patient characteristics with the odds of having axial manifestations were estimated using multinomial logistic regression (reference: Dx^-Sx^-).

RESULTS

Of 3393 patients included, 226 (6.7%) had Dx⁺Sx^-, 698 (20.6%) had Dx^-Sx⁺, 165 (4.9%) had Dx⁺Sx⁺, and 2304 (67.9%) had Dx^-Sx^-. Patients with Dx^-Sx⁺ or Dx⁺Sx⁺ were more frequently women and had a history of depression and fibromyalgia vs patients who had Dx^-Sx^-. Patients with Dx⁺Sx^- or Dx⁺Sx⁺ were more frequently HLA-B27 positive than those with Dx^-Sx^-. Fibromyalgia was significantly associated with increased odds of Dx⁺Sx^- or Dx⁺Sx⁺. Disease activity and PROs were worse in patients with Dx^-Sx⁺ or Dx⁺Sx⁺ than in those with Dx^-Sx^-.

CONCLUSION

Patients who had self-reported elevated spine symptoms, with or without physician-diagnosed axPsA, had worse quality of life and higher disease activity overall than patients without axial manifestations, suggesting an unmet need in this patient population.

Ultrasound shows swollen joints are the better proxy for synovitis than tender joints in DMARD-naïve early psoriatic arthritis

Objective

To evaluate the relationship between clinical examination/US synovitis in DMARD-naïve early PsA.

Methods

Eligible patients underwent matched clinical/US 44-joint assessment for tender and/or swollen joints (TJ/SJ) and US synovitis [grey scale (GS) ≥ 2 or power Doppler (PD) ≥ 1]. Statistical agreement between TJ/SJ, GS ≥ 2 and PD ≥ 1 was calculated by prevalence-adjusted and bias-adjusted κ (PABAK). To derive probabilities of GS ≥ 2/PD ≥ 1, mixed-effects logistic regression-modelled odds of US synovitis in TJ/SJ were conducted.

Results

In 155 patients, 5616 joints underwent clinical/US examination. Of these joints, 1039 of 5616 (18.5%) were tender, 550 of 5616 (9.8%) were swollen, 1144 of 5616 (20.4%) had GS ≥ 2, and 292 of 5616 (5.2%) had PD ≥ 1. GS ≥ 2 was most prevalent in concomitantly tender and swollen joints [205 of 462 (44%)], followed by swollen non-tender joints [32 of 88 (36.4%)], tender non-swollen joints [148 of 577 (25.7%)] and non-tender non-swollen joints (subclinical synovitis) [759 of 4489 (16.9%)]. Agreement between SJ/PD ≥ 1 was high at the individual joint level (82.6–96.3%, PABAK 0.65–0.93) and for total joints combined (89.9%, PABAK 0.80). SJ/GS ≥ 2 agreement was greater than between TJ/GS ≥ 2 [73.5–92.6% vs 51.0–87.4% (PABAK 0.47–0.85 vs PABAK 0.35–0.75), respectively]. Swelling was independently associated with higher odds of GS ≥ 2 [odds ratio (OR) (95% CI); 4.37 (2.62, 7.29); P < 0.001] but not tenderness [OR = 1.33 (0.87, 2.06); P = 0.192]. Swelling [OR = 8.78 (3.92, 19.66); P < 0.001] or tenderness [OR = 3.38 (1.53, 7.50); P = 0.003] was independently associated with higher odds of PD ≥ 1.

Conclusion

Synovitis (GS ≥ 2 and/or PD ≥ 1) was more likely in swollen joints than in tender joints in DMARD-naïve, early PsA. Agreement indicated that swollen joints were the better proxy for synovitis, adding to greater understanding between clinical and US assessments.

Comorbidities, pain and fatigue in psoriatic arthritis, psoriasis and healthy controls: a clinical cohort study

OBJECTIVES

To explore the prognostic value of pre-specified comorbidities on treatment outcomes in PsA, and to compare baseline data with cutaneous psoriasis without arthritis and healthy controls (HC).

METHODS

Patients initiating conventional synthetic/biological disease-modifying antirheumatic drugs were enrolled in this clinical observational cohort study, and data on comorbidities, and clinical and patient-reported outcomes were retrieved at baseline and after 4 months. Pearson's chi-squared tests were performed to investigate the prognostic value of pre-specified comorbidities and achievement of ACR20, DAPSA50 and MDA. Mann-Whitney U tests were used to compare OMERACT PsA Core Outcome Set (COS) measures at baseline and follow-up for the pre-specified comorbidities.

RESULTS

A total of 100 PsA patients were included at baseline. Statistically significantly fewer patients with obesity achieved DAPSA50 compared with patients without obesity (P =0.035), and fewer patients with hypertension (P =0.034) and Charlson Comorbidity Index (CCI) ≥1 (P =0.027), respectively, achieved MDA compared with patients without these comorbidities. Patients with obesity, hypertension, widespread pain, and CCI ≥1 had significantly worse COS measures at follow-up compared with patients without these comorbidities. At baseline, patients with PsA had higher disease burden compared with patients with cutaneous psoriasis and HC, including higher pain (P <0.001) and fatigue (P <0.001) scores, and more widespread pain (P =0.002).

CONCLUSION

Obesity, hypertension and CCI ≥1 were prognostic factors for poorer treatment outcome rates in PsA. Pain and fatigue were more frequently reported among patients with PsA compared with patients with cutaneous psoriasis and HC.

TRIAL REGISTRATION

The Danish National Committee on Health Research Ethics: H-15009080; Data Protection Agency: 2012-58-0004; ClinicalTrials.gov: NCT02572700.

Pain: A Review of Interleukin-6 and Its Roles in the Pain of Rheumatoid Arthritis

Pain is a major and common symptom reported as a top priority in patients with rheumatoid arthritis (RA). Intuitively, RA-related pain is often considered to be a natural consequence of peripheral inflammation, so treatment of RA is expected to manage pain concurrently as part of inflammation control. However, pain in patients with RA can be poorly correlated with objective measures of inflammation, for example, in patients who are otherwise in remission. Joint damage appears to account for only a fraction of this residual pain. Emerging evidence suggests that alteration of peripheral and central pain processing contributes to RA-related pain; this is parallel to, but somewhat independent of, joint inflammation. Interleukin (IL)-6 is a proinflammatory cytokine that contributes to the pathogenesis of RA. It exerts systemic effects via signaling through soluble forms of the IL-6 receptor (“trans-signaling”). Evidence from preclinical studies demonstrates that intra-articular IL-6 can produce long-lasting peripheral sensitization to mechanical stimulation and suggests an important role for IL-6 in central pain sensitization. This may be partly explained by its ability to activate neurons through trans-signaling, affecting nociceptive plasticity and nerve fiber regrowth. Local activity at neuron endings may culminate in altered pain processing in the central nervous system because of persistent signaling from sensitized peripheral neurons. Peripheral and central sensitization can promote the development of chronic pain, which can have a significant impact on patients’ health and quality of life. A proportion of pain in RA may be more appropriately managed as an entity separate from inflammation. Both the peripheral and central nervous systems should be recognized as important potential systems targeted by RA. The substantial burden of RA-related chronic pain suggests that pain should be a key focus in RA management and should be assessed and addressed early and separately from the inflammatory component.

Machine-learning-based knowledge discovery in rheumatoid arthritis-related registry data to identify predictors of persistent pain

Early detection of patients with chronic diseases at risk of developing persistent pain is clinically desirable for timely initiation of multimodal therapies. Quality follow-up registries may provide the necessary clinical data; however, their design is not focused on a specific research aim, which poses challenges on the data analysis strategy. Here, machine-learning was used to identify early parameters that provide information about a future development of persistent pain in rheumatoid arthritis (RA). Data of 288 patients were queried from a registry based on the Swedish Epidemiological Investigation of RA. Unsupervised data analyses identified the following 3 distinct patient subgroups: low-, median-, and high-persistent pain intensity. Next, supervised machine-learning, implemented as random forests followed by computed ABC analysis-based item categorization, was used to select predictive parameters among 21 different demographic, patient-rated, and objective clinical factors. The selected parameters were used to train machine-learned algorithms to assign patients pain-related subgroups (1000 random resamplings, 2/3 training, and 1/3 test data). Algorithms trained with 3-month data of the patient global assessment and health assessment questionnaire provided pain group assignment at a balanced accuracy of 70%. When restricting the predictors to objective clinical parameters of disease severity, swollen joint count and tender joint count acquired at 3 months provided a balanced accuracy of RA of 59%. Results indicate that machine-learning is suited to extract knowledge from data queried from pain- and disease-related registries. Early functional parameters of RA are informative for the development and degree of persistent pain.

Clinical predictors of multiple failure to biological therapy in patients with rheumatoid arthritis

BACKGROUND

Biological therapies have improved the clinical course and quality of life of rheumatoid arthritis (RA) patients. Despite the availability and effectiveness of these treatments, some patients experience multiple failures to biologic disease-modifying antirheumatic drugs (bDMARDs), constituting a particular challenge to clinicians.

OBJECTIVES

This study aims to determine the percentage of rheumatoid arthritis (RA) patients who fail to respond to subsequent bDMARDs, describe their characteristics, and identify specific baseline and early features during the first bDMARD as possible predictors of consecutive multiple bDMARD failure.

METHODS

This is a longitudinal study involving RA patients from the prospective biological cohort drawn from the La Paz University Hospital RA Registry (RA-Paz), starting a bDMARD during the years 2000 to 2019. Patients who presented insufficient response (due to primary or secondary inefficacy) to at least three bDMARDs or two bDMARDs with different mechanism of action were considered multi-refractory (MR-patients). Patients who achieved low disease activity or remission (by DAS-28) with the first bDMARD and maintained this over a follow-up period of at least 5 years were considered non-refractory (NR-patients).

RESULTS

A total of 41 out of 402 (10%) patients were MR-patients and 71 (18%) NR-patients. In the multivariate analysis, the presence of erosions, younger age, higher baseline DAS-28 and mostly achieving delta-DAS < 1.2 after 6 months of the first bDMARD (OR 11.12; 95% CI 3.34-26.82) were independently associated with being MR-patients to bDMARDs.

CONCLUSIONS

In our cohort, 10% of patients with RA were observed to have multi-refractoriness to bDMARDs. This study supports the contention that younger patients with erosive disease and especially the early absence of clinical response to the first bDMARDs are predictors of multi-refractoriness to consecutive biologics. Hence, patients with these characteristics should be monitored more closely and may benefit from personalized treatments.

Relation Between Fatigue and ACR Response in Patients With Psoriatic Arthritis Treated With Tumor Necrosis Factor Inhibitor Therapy: A Population-based Cohort Study

OBJECTIVE

The objective of this population-based cohort study was to investigate the association between fatigue with disease activity and drug survival in patients with psoriatic arthritis (PsA) receiving their first tumor necrosis factor inhibitor (TNFi).

METHODS

Data on patient characteristics, disease activity, and drug survival were obtained from the DANBIO database on all patients with PsA from 2006 through 2015. Information on comorbidities was obtained through linkage with the Danish National Patient Registry.

RESULTS

A total of 880 patients were eligible for analyses. Patients with upper median fatigue scores had statistically significant higher disease activity measures (Disease Activity Score in 28 joints based on C-reactive protein), pain, and Health Assessment Questionnaire (HAQ) scores; tender joint counts; comorbidities (Charlson Comorbidity Index ≥ 2); and current smoking status at baseline compared to patients with lower median fatigue scores (P < 0.05). In the upper median fatigue group, fewer patients achieved American College of Rheumatology (ACR) responses and improvements in visual analog scale (VAS) fatigue compared to patients in the lower median fatigue group. Kaplan-Meier curves showed shorter drug survival in patients in the upper median fatigue group compared with the lower median fatigue group at 6-month follow-up.

CONCLUSION

Fatigue remains a dominating symptom after TNFi treatment, and is associated with higher baseline disease activity, pain, and HAQ scores; more comorbidities; and increased risk of TNFi treatment discontinuation in a cohort of Danish patients with PsA. The agreement between ACR and VAS fatigue responses is weak to moderate, suggesting heterogeneity between experienced fatigue and joint inflammation.

Predictors, demographics and frequency of sustained remission and low disease activity in anti-tumour necrosis factor-treated rheumatoid arthritis patients

Objectives

To investigate the frequency and predictors of sustained 28-joint DAS (DAS28) remission and low disease activity (LDA) in patients receiving anti-TNF therapy and changes in responses over a 12 year period.

Methods

Data from the British Society for Rheumatology Biologics Registry for Rheumatoid Arthritis were used. Sustained remission and LDA were defined according to DAS28-ESR thresholds sustained for 6 months. The dataset was dichotomized into sequential chronological subgroups (2001–2010 and 2010–2013). Predictive variables were identified from a previous systematic review and modelled using multivariable logistic regression.

Results

Overall, 2144 (14.9%) and 3802 (26.3%) patients achieved sustained remission or LDA, respectively. Positive predictors of sustained remission/LDA included adalimumab (vs etanercept), greater patient global assessment, never- and ex-smoker status (vs current smoking), greater swollen joint count, more recent commencement of anti-TNF and MTX co-prescription (except in the 2010–2013 subgroup). Negative predictors of sustained remission and LDA included poor baseline functional status (HAQ), female gender, older age at starting anti-TNF, infliximab use (vs etanercept), increasing BMI and greater baseline ESR. Increasing tender joint count was negatively associated with sustained LDA only. The overall proportion of patients achieving sustained remission and LDA has increased significantly over time.

Conclusion

Sustained remission/LDA on anti-TNF treatment remains uncommon. Adalimumab use, greater patient global assessment, never- and ex-smoker status, greater swollen joint count, more recent commencement of anti-TNF and MTX co-prescription are associated with achievement of sustained remission/LDA. However, co-prescription of MTX was not associated with an increased likelihood of achieving sustained remission or LDA in the analysis of more recent anti-TNF responses.

Brain Correlates of Continuous Pain in Rheumatoid Arthritis as Measured by Pulsed Arterial Spin Labeling

OBJECTIVE

Central nervous system pathways involving pain modulation shape the pain experience in patients with chronic pain. The aims of this study were to understand the mechanisms underlying pain in patients with rheumatoid arthritis (RA) and to identify brain signals that may serve as imaging markers for developing targeted treatments for RA-related pain.

METHODS

Patients with RA and matched control subjects underwent functional magnetic resonance imaging, using pulsed arterial spin labeling. The imaging conditions included 1) resting state, 2) low-intensity stimulus, and 3) high-intensity stimulus. Stimuli consisted of mechanical pressure applied to metacarpophalangeal (MCP) joints with an automated cuff inflator. The low-intensity stimulus was inflation to 30 mm Hg. The high-intensity stimulus was the amount of pressure required to achieve a pain intensity rating of 40 on a 100-point scale for each RA patient, with the same amount of pressure used in the matched control.

RESULTS

Among RA patients, regional cerebral blood flow (rCBF) in the medial frontal cortex and dorsolateral prefrontal cortex increased during both low-pressure and high-pressure stimulation. No rCBF changes were observed in pain-free controls. Region-of-interest analyses in RA patients showed that baseline rCBF in the medial frontal cortex was negatively correlated with the pressure required for the high-intensity stimulus and positively correlated with pain induced by the low-intensity stimulus. Baseline rCBF was also marginally correlated with disease activity). Regional CBF during high pain was positively correlated with pain severity and pain interference.

CONCLUSION

In response to clinically relevant joint pain evoked by pressure applied to the MCP joint, neural processing in the medial frontal cortex increases and is directly associated with clinical pain in patients with RA.

Pain Mechanisms and Ultrasonic Inflammatory Activity as Prognostic Factors in Patients With Psoriatic Arthritis: A Prospective Cohort Study

OBJECTIVE

To study the prognostic value of widespread pain and of musculoskeletal ultrasound (US) examination for subsequent treatment outcomes in patients with psoriatic arthritis (PsA).

METHODS

An exploratory prospective cohort study enrolled patients with PsA initiating biologic or conventional synthetic disease-modifying antirheumatic drugs in routine care. Clinical, US, and patient-reported measures were collected at baseline and after 4 months. Widespread nonarthritic pain (WP) was defined as a Widespread Pain Index score of ≥4 with pain in ≥4 of 5 regions. PsA activity by US was defined as color Doppler (yes/no) in selected entheses, joints, or tendons. The main response criteria included the American College of Rheumatology 20% improvement, the Disease Activity in Psoriatic Arthritis 50% improvement, and minimal disease activity. The primary analyses were age- and sex-adjusted logistic regression.

RESULTS

WP was present in 24 of 69 included patients (35%) and was associated with worse patient-reported and composite baseline measures, while US and other objective findings were similar to those in patients without WP. The odds of reaching minimal disease activity after 4 months were significantly greater for patients enrolled without WP (odds ratio 18.43 [95% confidence interval 1.51, 224.41]; P = 0.022), while WP did not impair other response measures. Patients with baseline color Doppler activity (n = 42 [61%]) had a worse objective PsA burden, but their chance of treatment response was comparable to those without color Doppler.

CONCLUSION

More than one-third of patients with PsA presented with WP, which was associated with worse patient-reported scores and failure to achieve minimal disease activity following conventional synthetic or biologic disease-modifying antirheumatic drug therapy. PsA activity by color Doppler US had no influence on subsequent treatment response in this PsA cohort.

Usefulness of composite indices in the assessment of joint involvement in systemic lupus erythematosus patients: correlation with ultrasonographic score

Specific indices are not available to evaluate systemic lupus erythematosus (SLE) joint involvement; indeed, the application of indices validated for rheumatoid arthritis has been suggested. We evaluated the usefulness of organ specific composite indices, i.e. the Disease Activity Score on 28 joints (DAS28), Simplified Disease Activity Index (SDAI), Clinical Disease Activity Index (CDAI), and the ratio of swollen to tender joints (STR), to assess SLE joint activity by analyzing the correlation between these indices and ultrasonography (US) inflammatory status. We evaluated SLE patients with arthralgia and/or arthritis: the above-mentioned indices were calculated and the SLE Disease Activity Index 2000 (SLEDAI-2k) was applied to assess global disease activity. US of I-V metacarpophalangeal, I-V proximal interphalangeal, wrist, and knee bilateral was performed. Synovial effusion/hypertrophy and power Doppler findings were scored according to a semi-quantitative scale (0-3) to obtain an inflammatory total score (0-216). One hundred and six patients (M/F 7/99, median age 49.5 years (IQR 17.0), median disease duration 8.5 years (IQR 17.0)) were enrolled. We identified a positive correlation between US score and DAS28-CRP ( r = 0.3, p = 0.007), STR ( r = 0.42, p = 0.0005), SDAI ( r = 0.33, p = 0.02), CDAI ( r = 0.29, p = 0.03); US score reflected different levels of clinimetric joint activity. In conclusion, we suggest the ability of composite indices in detecting SLE joint inflammation and their possible real-life use.

Is a Fundamental Change in the Interpretation of Rheumatoid Arthritis Disease Activity Necessary?

Disease Activity Score (DAS) composite models are moderately precise and robust measures of disease severity when they are used in rheumatoid arthritis (RA) cohorts. They are less so when used for individual patients. This is because subjective components, patient global assessment of well-being and tender joint count, modified by factors other than RA biological disease activity, often obfuscate interpretation of disease activity. Comorbidities, especially distress, can disproportionately inflate these components. Fibromyalgia, essentially synonymous with distress, pain augmentation, and depression, is a common comorbidity. Its presence and severity can be determined by the Polysymptomatic Distress Scale (PSD). The differential effects of distress and fibromyalgia syndrome on the DAS can be demonstrated by manipulating information already there: the arithmetic differences or ratios of the tender joint count and swollen joint count and comparison of the modified disease activity score with 28 joints to the disease activity score with 28 joints-patient (DAS28-derived indices that measure the contribution of the relatively objective or relatively subjective components, respectively). The potentially more objective multibiomarker disease activity might also be used to test the severity of biological RA disease activity. These tools may be used to elucidate disproportionate values for subjective DAS model components, which then should facilitate identification of the underlying process factors, including depression, for potential treatment.

The subjective components of the Disease Activity Score 28-joints (DAS28) in rheumatoid arthritis patients and coexisting fibromyalgia

To determine the contribution of fibromyalgia (FM) to the subjective components of the Disease Activity Score 28-joints (DAS28) in patients with rheumatoid arthritis (RA), and to analyse the discriminatory performance of the derived DAS28 patient-reported components (DAS28-P) to identify patients with fibromyalgic RA. Consecutive RA patients underwent clinical and clinimetric assessment. The DAS28-P index was derived from the components of the DAS28 scores by rearranging the DAS28-ESR formula. Patients were distinguished by the presence of FM. Student parametric t tests or Mann-Whitney non-parametric U tests were used to determine any between-group differences. Receiver operating characteristic (ROC) curve analysis was used to test the ability of the DAS28-P index to distinguish patients with RA and those with fibromyalgic RA. The study involved 292 RA patients (80.5% females, mean age 63 years) with a mean disease duration of 11.6 ± 8.5 years. Forty-three patients (14.7%) had concomitant FM, and significantly higher tender joint count (p < 0.001), pain numerical rating scale, global health status (p = 0.007), and DAS28 scores (p = 0.006) than those without FM. The DAS28-P values were also significantly higher in the patients with FM (0.68 ± 0.09 vs 0.58 ± 0.06; p < 0.001). The discriminatory power of the DAS28-P was very good (area under the ROC of 0.858, optimal cut-off value of 0.631). The presence of FM strongly influences the DAS28 results. The assessment of patient-reported components to the DAS28 through the DAS28-P can be a useful way to identify patients with fibromyalgic RA.

Pain and pain mechanisms in patients with inflammatory arthritis: A Danish nationwide cross-sectional DANBIO registry survey

Background

Central pain mechanisms may be prominent in subsets of patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and other spondyloarthritis (SpA). The painDETECT questionnaire (PDQ) identifies neuropathic pain features, which may act as a proxy for centrally mediated pain.

The objectives were to quantify and characterize pain phenotypes (non-neuropathic vs. neuropathic features) among Danish arthritis patients using the PDQ, and to assess the association with on-going inflammation.

Methods

The PDQ was included onto the DANBIO touch screens at 22 departments of Rheumatology in Denmark for six months. Clinical data and patient reported outcomes were obtained from DANBIO. A PDQ-score >18 indicated neuropathic pain features, 13–18 unclear pain mechanism and <13 non-neuropathic pain.

Results

Pain data (visual analogue scale, VAS) was available for 15,978 patients. 7,054 patients completed the PDQ (RA: 3,826, PsA: 1,180, SpA: 1,093). 52% of all patients and 63% of PDQ-completers had VAS pain score ≥ 30 mm. The distribution of the PDQ classification-groups (<13/ 13-18/ >18) were; RA: 56%/24%/20%. PsA: 45%/ 27%/ 28%. SpA: 55% / 24%/ 21%. More patients with PsA had PDQ score >18 compared to RA and SpA (p<0.001). For PDQ > 18 significantly higher scores were found for all patient reported outcomes and disease activity scores. No clinical difference in CRP or swollen joint count was found. Logistic regression showed increased odds for having VAS pain ≥39 mm (the median) for a PDQ-score >18 compared to <13 (OR = 10.4; 95%CI 8.6–12.5).

Conclusions

More than 50% of the Danish arthritis patients reported clinically significant pain. More than 20% of the PDQ-completers had indication of neuropathic pain features, which was related to a high pain-level. PDQ-score was associated with DAS28-CRP and VAS pain but not with indicators of peripheral inflammation (CRP and SJC). Thus, pain classification by PDQ may assist in mechanism-based pain treatment.

Discordance between tender and swollen joint count as well as patient's and evaluator's global assessment may reduce likelihood of remission in patients with rheumatoid arthritis and psoriatic arthritis: data from the prospective multicentre NOR-DMARD study

Objective

To investigate the predictive value of discordance between (1) tender and swollen joint count and (2) patient's and evaluator's global assessment on remission in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA).

Methods

From the prospective, multicentre Norwegian-Disease-Modifying Antirheumatic Drug study, we included patients with RA and PsA starting first-time tumour necrosis factor inhibitors and DMARD-naïve patients starting methotrexate between 2000 and 2012. The predictive value of ΔTSJ (tender minus swollen joint counts) and ΔPEG (patient's minus evaluator's global assessment) on remission was explored in prespecified logistic regression models adjusted for age, sex, disease duration and smoking.

Results

A total of 2735 patients with RA and 1236 patients with PsA were included (mean (SD) age 55.0 (13.5)/48.3 (12.4) years, median(range) disease duration 0.7 (0.0–58.0)/1.3 (0.0–48.3) years, 69.7/48.4% females). Baseline ΔTSJ/ΔPEG reduced the likelihood of achieving DAS28<2.6, SDAI≤3.3, CDAI≤2.8, ACR/EULAR Boolean and DAPSA<4 remission after 3 and 6 months in RA (OR 0.95–0.97, p<0.001/OR 0.96–0.99, p≤0.01) and PsA (OR 0.91–0.94, p≤0.004/OR 0.89–0.99, p≤0.002), except for ΔPEG and 6-month DAS28 remission in PsA.

Conclusions

Discordance between patient's and physician's evaluation of disease activity reflected through ΔTSJ and partly ΔPEG may reduce likelihood of remission in RA and PsA. The findings are relevant for use of the treat-to-target strategy in individual patients.

Comparative assessment of clinical response in patients with rheumatoid arthritis between PF-05280586, a proposed rituximab biosimilar, and rituximab

AIMS

To evaluate potential differences between PF-05280586 and rituximab sourced from the European Union (rituximab-EU) and USA (rituximab-US) in clinical response (Disease Activity Score in 28 Joints [DAS28] and American College of Rheumatology [ACR] criteria), as part of the overall biosimilarity assessment of PF-05280586.

METHODS

A randomised, double-blind, pharmacokinetic similarity trial was conducted in patients with active rheumatoid arthritis refractory to anti-tumour necrosis factor therapy on a background of methotrexate. Patients were treated with 1000 mg of PF-05280586, rituximab-EU or rituximab-US on days 1 and 15 and followed over 24 weeks for pharmacokinetic, clinical response and safety assessments. Key secondary end points were the areas under effect curves for DAS28 and ACR responses. Mean differences in areas under effect curves were compared against respective reference ranges established by observed rituximab-EU and rituximab-US responses using longitudinal nonlinear mixed effects models.

RESULTS

The analysis included 214 patients. Demographics were similar across groups with exceptions in some baseline disease characteristics. Baseline imbalances and group-to-group variation were accounted for by covariate effects in each model. Predictions from the DAS28 and ACR models tracked the central tendency and distribution of observations well. No point estimates of mean differences were outside the reference range for DAS28 or ACR scores. The probabilities that the predicted differences between PF-05280586 vs. rituximab-EU or rituximab-US lie outside the reference ranges were low.

CONCLUSIONS

No clinically meaningful differences were detected in DAS28 or ACR response between PF-05280586 and rituximab-EU or rituximab-US as the differences were within the pre-specified reference ranges.

TRIAL REGISTRATION NUMBER

NCT01526057.

Pain mechanisms and ultrasonic inflammatory activity as prognostic factors in patients with psoriatic arthritis: protocol for a prospective, exploratory cohort study

INTRODUCTION

Persistent pain is a major concern for patients with psoriatic arthritis (PsA). Pain may be due to inflammatory activity or augmented central pain processing. Unawareness of the origin and mechanisms of pain can lead to misinterpretation of disease activity (by composite scores) and erroneous treatments. Ultrasonography (US) is a highly sensitive method to detect tissue inflammation. Evaluating pain mechanisms in relation to US measures may prove valuable in predicting response to treatment in PsA.

AIMS

To study the association and prognostic value of pain mechanisms, ultrasonic activity and clinical outcomes in patients with PsA who intensify antirheumatic treatment.

METHODS AND ANALYSES

100 participants >18 years of age with PsA who initiate or switch antirheumatic treatment (biologicals and/or conventional synthetic disease-modifying antirheumatic drugs (DMARDs)) will be prospectively recruited from outpatient clinics in Copenhagen. All data (demographics, clinical, imaging, blood samples and patient-reported outcomes) will be collected at baseline and after 4 months. Pain is assessed by the PainDETECT Questionnaire, Visual Analogue Scale for pain, Swollen to Tender Joint Count Ratio, Widespread Pain Index and tender point examination. The association between pain variables and clinical/US characteristics will be described by correlation analyses. The predictive value of pain measures and baseline US scores on treatment response will be analysed with regression models. Outcomes are composite and clinical, as well as patient reported.

ETHICS AND DISSEMINATION

The study is approved by the ethics committee of the Capital Region of Denmark (H-15009080) and has been designed in cooperation with patient research partners. The study is registered at clinicaltrials.gov (number NCT02572700). Results will be disseminated through publication in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02572700, Pre-results.

Correlations between fatigue and disease duration, disease activity, and pain in patients with rheumatoid arthritis: a systematic review

OBJECTIVES

Rheumatoid arthritis (RA) patients suffer from disabling fatigue but the causes of this condition are unknown. Our aim was to assess which of the variables disease activity, disease duration, and pain is associated with fatigue.

METHOD

We conducted a systematic literature search in MEDLINE and EMBASE, followed by selection of studies according to set criteria, data extraction, and statistical analyses of the relationships in RA between fatigue and the following covariates: disease duration, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the 28-joint Disease Activity Score (DAS28), swollen to tender joint count ratio (STR), and pain. Linear regression analyses of fatigue regressed on each of the six covariates, and a multiple regression analysis where fatigue was regressed on the six covariates through a forward selection procedure was carried out with construction of correlation measures between fatigue and the covariates.

RESULTS

A total of 121 studies were included in the analyses, including > 100 000 RA patients. A high level of fatigue was seen even in well-treated patients, demonstrating fatigue as a major problem in RA. Fatigue was found to be positively correlated with pain, CRP, DAS28, and ESR but not with the STR or disease duration, with pain as the overall domineering factor.

CONCLUSIONS

Fatigue has a substantial influence on the lives of RA patients, independent of disease duration. Pain is the domineering factor in the experience and degree of fatigue. Disease activity is positively correlated to fatigue but does not contribute substantially when pain is considered. Optimal pain relief is therefore an important part of the treatment to improve fatigue in RA.