External validation of six COVID-19 prognostic models for predicting mortality risk in older populations in a hospital, primary care, and nursing home setting

OBJECTIVES

To systematically evaluate the performance of COVID-19 prognostic models and scores for mortality risk in older populations across three health-care settings: hospitals, primary care, and nursing homes.

STUDY DESIGN AND SETTING

This retrospective external validation study included 14,092 older individuals of ≥70 years of age with a clinical or polymerase chain reaction-confirmed COVID-19 diagnosis from March 2020 to December 2020. The six validation cohorts include three hospital-based (CliniCo, COVID-OLD, COVID-PREDICT), two primary care-based (Julius General Practitioners Network/Academisch network huisartsgeneeskunde/Network of Academic general Practitioners, PHARMO), and one nursing home cohort (YSIS) in the Netherlands. Based on a living systematic review of COVID-19 prediction models using Prediction model Risk Of Bias ASsessment Tool for quality and risk of bias assessment and considering predictor availability in validation cohorts, we selected six prognostic models predicting mortality risk in adults with COVID-19 infection (GAL-COVID-19 mortality, 4C Mortality Score, National Early Warning Score 2-extended model, Xie model, Wang clinical model, and CURB65 score). All six prognostic models were validated in the hospital cohorts and the GAL-COVID-19 mortality model was validated in all three healthcare settings. The primary outcome was in-hospital mortality for hospitals and 28-day mortality for primary care and nursing home settings. Model performance was evaluated in each validation cohort separately in terms of discrimination, calibration, and decision curves. An intercept update was performed in models indicating miscalibration followed by predictive performance re-evaluation.

MAIN OUTCOME MEASURE

In-hospital mortality for hospitals and 28-day mortality for primary care and nursing home setting.

RESULTS

All six prognostic models performed poorly and showed miscalibration in the older population cohorts. In the hospital settings, model performance ranged from calibration-in-the-large -1.45 to 7.46, calibration slopes 0.24-0.81, and C-statistic 0.55-0.71 with 4C Mortality Score performing as the most discriminative and well-calibrated model. Performance across health-care settings was similar for the GAL-COVID-19 model, with a calibration-in-the-large in the range of -2.35 to -0.15 indicating overestimation, calibration slopes of 0.24-0.81 indicating signs of overfitting, and C-statistic of 0.55-0.71.

CONCLUSION

Our results show that most prognostic models for predicting mortality risk performed poorly in the older population with COVID-19, in each health-care setting: hospital, primary care, and nursing home settings. Insights into factors influencing predictive model performance in the older population are needed for pandemic preparedness and reliable prognostication of health-related outcomes in this demographic.

Towards a simplified fluid-sensitive MRI protocol in small joints of the hand in early arthritis patients: reliability between modified Dixon and regular Gadolinium enhanced TSE fat saturated MRI-sequences

OBJECTIVE

MRI of small joints plays an important role in the early detection and early treatment of rheumatoid arthritis. Despite its sensitivity to demonstrate inflammation, clinical use is hampered by accessibility, long scan time, intravenous contrast, and consequent high costs. To improve the feasibility of MRI implementation in clinical practice, we introduce a modified Dixon sequence, which does not require contrast and reduces total acquisition time to 6 min. Because the reliability in relation to conventional MRI sequences is unknown, we determined this.

METHODS

In 29 consecutive early arthritis patients, coronal and axial T2-weighted modified Dixon acquisitions on 3.0 T MRI scanner were acquired from metacarpophalangeal 2-5 to the wrist, followed by the standard contrast-enhanced protocol on 1.5 T extremity MRI. Two readers scored osteitis, synovitis and tenosynovitis (summed as total MRI-inflammation), and erosions (all summed as total Rheumatoid Arthritis MRI Score (RAMRIS)). Intraclass correlation coefficients (ICCs) between readers, and comparing the two sequences, were studied. Spearman correlations were determined.

RESULTS

Performance between readers was good/excellent. Comparing modified Dixon and conventional sequences revealed good/excellent reliability: ICC for total MRI-inflammation score was 0.84 (95% CI:0.70-0.92), for erosions 0.90 (95% CI:0.79-0.96), and for the total RAMRIS score 0.88 (95% CI:0.77-0.94). The scores of total MRI-inflammation, total erosions, and total RAMRIS were highly correlated (ρ = 0.80, ρ = 0.81, ρ = 0.82, respectively).

CONCLUSION

The modified Dixon protocol is reliable compared to the conventional MRI protocol, suggesting it is accurate to detect MRI inflammation. The good correlation may be the first step towards a patient-friendly, short and affordable MRI protocol, which can facilitate the implementation of MRI for early detection of inflammation in rheumatology practice.

The Role of Genetics in Clinically Suspect Arthralgia and Rheumatoid Arthritis Development: A Large Cross-Sectional Study

OBJECTIVE

To investigate whether established genetic predictors for rheumatoid arthritis (RA) differentiate healthy controls, patients with clinically suspect arthralgia (CSA), and RA patients.

METHODS

Using analyses of variance, chi-square tests, and mean risk difference analyses, we investigated the association of an RA polygenic risk score (PRS) and HLA shared epitope (HLA-SE) with all participant groups, both unstratified and stratified for anti-citrullinated protein antibody (ACPA) status. We used 3 separate data sets sampled from the same Dutch population (1,015 healthy controls, 479 CSA patients, and 1,146 early classified RA patients). CSA patients were assessed for conversion to inflammatory arthritis over a period of 2 years, after which they were classified as either CSA converters (n = 84) or CSA nonconverters (n = 395).

RESULTS

The PRS was increased in RA patients (mean ± SD PRS 1.31 ± 0.96) compared to the complete CSA group (1.07 ± 0.94) and compared to CSA converters (1.12 ± 0.94). In ACPA- strata, PRS distributions differed strongly when comparing the complete CSA group (mean ± SD PRS 1.05 ± 0.94) and CSA converters (0.97 ± 0.87) to RA patients (1.20 ± 0.94), while in the ACPA+ strata, the complete CSA group (1.25 ± 0.99) differed clearly from healthy controls (1.05 ± 0.94) and RA patients (1.41 ± 0.96). HLA-SE was more prevalent in the RA group (prevalence 0.64) than the complete CSA group (0.45), with small differences between RA patients and CSA converters (0.64 versus 0.60) and larger differences between CSA converters and CSA nonconverters (0.60 versus 0.42). HLA-SE prevalence differed more strongly within the ACPA+ strata as follows: healthy controls (prevalence 0.43), CSA nonconverters (0.48), complete CSA group (0.59), CSA converters (0.66), and RA patients (0.79).

CONCLUSION

We observed that genetic predisposition increased across pre-RA participant groups. The RA PRS differed in early classified RA and inflammatory pre-disease stages, regardless of ACPA stratification. HLA-SE prevalence differed between arthritis patients, particularly ACPA+ patients, and healthy controls. Genetics seem to fulfill different etiologic roles.

The course of fatigue during the development of rheumatoid arthritis and its relation with inflammation: a longitudinal study

OBJECTIVE

Fatigue is a prominent and disabling symptom in patients with rheumatoid arthritis (RA), that is only partially explained by inflammation and responds poorly to DMARD-therapy. We hypothesized that inflammation explains fatigue to a larger extent in the phase of clinically suspect arthralgia (CSA), when persistent clinical arthritis is still absent and fatigue has not yet become chronic. We therefore studied the course of fatigue in CSA during progression to RA and the association with inflammation at CSA-onset and at RA-diagnosis.

METHODS

600 consecutive CSA-patients were followed for RA-development. Additionally, 710 early RA-patients were studied at diagnosis. Fatigue was assessed every study visit and expressed on a 0-100 scale. Inflammation was measured with the DAS44-CRP, with and without including subclinical inflammation. The course of fatigue over time was studied with linear mixed models. Associations between fatigue and inflammation were studied with linear regression. Analyses were stratified by ACPA-status.

RESULTS

In 88 CSA-patients who developed RA, pre-arthritis fatigue-levels increased gradually with 7 points/year, towards 48 (95%CI=41-55) at RA-development (P=ns). Fatigue decreased in CSA-patients who did not develop RA (4 points/year, P<0.001). At CSA-onset, inflammation was associated with fatigue (β=18, meaning 18 points more fatigue per point increase DAS-score, P<0.01). This association was stronger than at RA-diagnosis (β=5, P<0.001). Fatigue-levels were lower in ACPA-positive pre-RA, but its association with inflammation was stronger compared to ACPA-negative pre-RA.

CONCLUSION

Fatigue increased gradually during progression from arthralgia to clinical arthritis, and fatigue was better explained by inflammation in CSA than in RA. This implies a 'phase-dependent relation' between inflammation and fatigue.

Risk of death in nursing home residents after COVID-19 vaccination

Objectives

In the first months of 2021, the Dutch COVID-19 vaccination campaign was disturbed by reports of death in Norwegian nursing homes (NHs) after vaccination. Reports predominantly concerned persons >65 years of age with 1 or more comorbidities. Also, in the Netherlands adverse events were reported after COVID-19 vaccination in this vulnerable group. Yet, it was unclear whether a causal link between vaccination and death existed. Therefore, we investigated the risk of death after COVID-19 vaccination in Dutch NH residents compared with the risk of death in NH residents prior to the COVID-19 pandemic.

Design

Population-based longitudinal cohort study with electronic health record data.

Setting and Participants

We studied Dutch NH residents from 73 NHs who received 1 or 2 COVID-19 vaccination(s) between January 13 and April 16, 2021 (n = 21,762). As a historical comparison group, we included Dutch NH residents who were registered in the same period in 2019 (n = 27,591).

Methods

Data on vaccination status, age, gender, type of care, comorbidities, and date of NH entry and (if applicable) discharge or date of death were extracted from electronic health records. Risk of death after 30 days was evaluated and compared between vaccinated residents and historical comparison residents with Kaplan-Meier and Cox regression analyses. Regression analyses were adjusted for age, gender, comorbidities, and length of stay.

Results

Risk of death in NH residents after one COVID-19 vaccination (regardless of whether a second vaccination was given) was decreased compared with historical comparison residents from 2019 (adjusted HR 0.77, 95% CI 0.69-0.86). The risk of death further decreased after 2 vaccinations compared with the historical comparison group (adjusted HR 0.57, 95% CI 0.50-0.64).

Conclusions and Implications

We found no indication that risk of death in NH residents is increased after COVID-19 vaccination. These results indicate that COVID-19 vaccination in NH residents is safe and could reduce fear and resistance toward vaccination.

POS0593 THE COURSE OF FATIGUE AND ITS RELATION WITH INFLAMMATION DURING THE DEVELOPMENT OF RHEUMATOID ARTHRITIS: A LONGITUDINAL STUDY

Background

Fatigue is a prominent and disabling symptom in patients with rheumatoid arthritis (RA), that is only partially explained by inflammation and responds poorly to DMARD-therapy. We hypothesized that inflammation explains fatigue to a larger extent in the phase of clinically suspect arthralgia (CSA), when clinical arthritis is still absent and fatigue has not yet become chronic.

Objectives

To study the course of fatigue in CSA during progression to RA and the association with inflammation at CSA-onset and at RA-diagnosis.

Methods

600 consecutive CSA-patients were followed for RA-development (median follow-up 25 months). Additionally, 710 early RA-patients were studied at diagnosis. Fatigue was assessed every study visit and expressed on a scale of 0-100. The DAS44-CRP was used to measure inflammation (with SJC=0 in CSA). The course of fatigue over time was studied with linear mixed models. Associations between fatigue and inflammation were studied with linear regression, corrected for sex. Analyses were stratified by ACPA-status.

Results

In 88 CSA-patients who developed RA, pre-arthritis fatigue-levels increased gradually with 7/year (95%CI= -2 to 16, p=0.13), towards 48 at RA-development. Fatigue decreased in CSA-patients who did not develop RA (-4/year, 95%CI= -6 to -3, p<0.001) (see Figure 1). At CSA-onset, inflammation was associated with fatigue (β=18, meaning 18 points more fatigue per point increase DAS-score, 95%CI=7-28, p=0.001). This association was stronger than at RA-diagnosis (β=5, 95%CI=3-7, p<0.001). Fatigue-levels increased towards RA-development in both ACPA-subtypes, but were on overall average higher in ACPA-negative CSA than ACPA-positive CSA (mean difference in fatigue of 13, 95%CI=1-24, p=0.027). However, the association between fatigue and inflammation was stronger in ACPA-positive compared to ACPA-negative CSA.

Conclusion

Fatigue increased gradually during progression from arthralgia to clinical arthritis, and fatigue was better explained by inflammation in CSA than in RA. This implies a ‘phase-dependent relation’ between inflammation and fatigue.

References

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Disclosure of Interests

None declared.

During development of rheumatoid arthritis, intermetatarsal bursitis may occur before clinical joint swelling: a large imaging study in patients with clinically suspect arthralgia

Objectives

Intermetatarsal bursitis (IMB) represents juxta-articular synovial inflammation of the intermetatarsal bursae. Recent MRI studies identified IMB as feature of early RA, but whether IMB already occurs in the pre-arthritic phase is unknown. We performed a large MRI study in clinically suspect arthralgia (CSA) to assess the occurrence and prognostic value of IMB.

Methods

A total of 577 consecutive CSA patients underwent contrast-enhanced MRI of the forefoot, metacarpophalangeal joints and wrist. MRIs were evaluated for subclinical synovitis/tenosynovitis/osteitis in line with the RA MRI scoring system (summed as RAMRIS inflammation) and for IMB. IMB was considered present if uncommon in the general population at the same location (i.e. size scored above the 95th percentile in age-matched symptom-free controls). The relation of IMB with other MRI-detected subclinical inflammation (synovitis/tenosynovitis/osteitis) was studied. Cox-regression assessed the association with clinical arthritis development during median 25 months follow-up. ACPA stratification was performed.

Results

At presentation with CSA, 23% had IMB. IMB was more frequent in ACPA-positive than ACPA-negative CSA (47% vs 19%, P < 0.001). Patients with IMB were more likely to also have subclinical synovitis [OR 3.4 (95% CI 1.8, 6.5)] and tenosynovitis [5.9(2.8, 12.6)]. IMB conferred higher risk of developing arthritis [HR 1.6(1.0–2.7) adjusted for other subclinical inflammation]. IMB-presence predicted arthritis development in ACPA-positive CSA [adjusted HR 2.2(1.0–4.7)], but not in ACPA-negative CSA-patients [0.8(0.4–1.7)].

Conclusion

Approximately a quarter of CSA patients have IMB, which is frequently accompanied by subclinical synovitis and tenosynovitis. IMB precedes development of clinical arthritis, particularly in ACPA-positive CSA. These results reinforce the notion that juxta-articular synovial inflammation is involved in the earliest phases of RA development.

Performance of an artificial intelligence algorithm to detect atrial fibrillation on a 24-hour continuous photoplethysmography recording using a smartwatch: ACURATE study

Background

In the awakening era of mobile health, wearable devices capable of detecting atrial fibrillation (AF) are on the rise. Smartwatches and wristbands are equipped with photoplethysmography (PPG) technology that enables (semi)continuous rhythm monitoring. These devices have been pioneered already in a few screening trials. However, such devices are being spread among consumers at a pace that is not paralleled by the evidence supporting their clinical performance. This imbalance reflects the urgent need for validation studies.

Purpose

To determine the diagnostic performance of an artificial intelligence algorithm to detect AF using photoplethysmography acquired by a smartwatch.

Methods

One hundred patients (≥18 years) without a pacemaker-dependent heart rhythm who were referred to a university hospital or a large tertiary hospital for elective 24-hour ECG Holter monitoring were asked to wear a continuous PPG monitoring smartwatch (i.e. Samsung GWA2 or Empatica E4) simultaneously with the Holter. All activities of daily life were allowed. The ECG trace and PPG waveform were synchronised and fragmented in one-minute fragements. The one-minute ECG fragments were labelled as AF, non-AF, or insufficient quality based on the routine clinical interpretation of the 24-hour Holter (i.e. software + physician overreading). The one-minute PPG fragments were analysed by an artificial intelligence (AI) algorithm (i.e. FibriCheck) and were given the same labels. Diagnostic metrics of the PPG AI algorithm were calculated with respect to the ECG interpretation, for all fragments with sufficient quality for both PPG and ECG.

Results

Four patients had to be excluded due to technical error (3 Holter errors, 1 smartwatch error). The mean age in the remaining study population (n=96) was 59±16 years, 51 (53%) were men and 15 (15.6%) were known with permanent AF. In this population, simultaneous ECG and PPG monitoring was recorded for 115,245 one-minute fragments. Fragments of insufficient quality for ECG (n=1,454; 1.3%), PPG (n=25,704; 22.3%) or both (n=15,362; 13.3%) were excluded. PPG fragments were more frequently of insufficient quality (p&lt;0.001). AF was present in 10,255 (14.1%) of the resulting 72,725 high-quality one-minute fragments. The sensitivity of PPG to detect AF was 93.4% (CI 92.9% - 93.8%). The specificity of PPG to exclude AF was 98.4% (CI 98.3% - 98.5%). As a result, the overall accuracy of the PPG algorithm on one-minute fragment level was 97.7% (CI 97.6%- 97.8%).

Conclusion

Continuous out-of-hospital PPG monitoring using a smartwatch in combination with an AI algorithm can accurately discriminate between AF and non-AF rhythms in a heterogenous patient population. PPG quality is more often affected than ECG quality during daily life activities.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Research Foundation-Flanders, Strategic Basic Research Fund

Assessment of heart rate agreement on continuous photoplethysmography monitoring using a smartwatch versus beat-to-beat synchronized ECG monitoring

Background

In the awakening era of mobile health, wearables equipped with photoplethysmography (PPG) technology to monitor the heart rate (HR) and rhythm are on the rise. Smartwatches and wristbands enable HR monitoring for consumers at massive scale. Unfortunately, once consumers become patients, physicians are limited by insufficient evidence to support the clinical use of PPG based wearables. Accurate identification of heartbeats is the first step in the interpretation of PPG traces and should be validated.

Purpose

To assess the agreement between continuous PPG monitoring using a smartwatch and continuous ECG Holter monitoring in the identification of heartbeats and calculation of the HR.

Methods

One hundred patients (≥18 years) without a pacemaker-dependent heart rhythm who were referred to a university hospital and a large tertiary hospital for elective 24-hour ECG Holter monitoring were asked to wear a continuous PPG monitoring smartwatch (i.e. Samsung GWA2 or Empatica E4) simultaneously with the 24-hour Holter monitor. All activities of daily life were allowed. The ECG trace and PPG waveform were synchronised and fragmented in one-minute fragments. The one-minute ECG fragments were labelled as AF, non-AF, or insufficient quality based on the routine clinical interpretation (i.e. software + physician overreading), and the average HR during each fragment was calculated by Holter algorithm. The PPG fragments were analysed by an artificial intelligence (AI) algorithm (i.e. FibriCheck) that labelled fragments as sufficient or insufficient quality, identified the number of heartbeats and calculated the HR. The agreement between the HR on ECG and PPG in sufficient quality tracings was analysed with linear regression, Pearson's product-moment correlation and Bland-Altman analysis. A subanalysis was performed for AF rhythm and non-AF rhythms.

Results

A total of 72,725 simultaneous ECG and PPG one-minute fragments were recorded in 96 patients, after excluding 4 patients (due to 3 Holter and 1 smartwatch technical error) and 42,520 minutes (36.9%) of insufficient quality (ECG 1,454 (1.3%); PPG 25,704 (22.3%), ECG and PPG 15,362 (13.3%)). The correlation (r=0.935) between ECG and PPG HR was statistically significant (CI 0.934–0.936; P&lt;0.001), with a mean difference between ECG and PPG of 0.8bpm. The lower and upper limit boundary (LLB and ULB; defined as ±1.96 SD) were −8.0bpm and 9.7bpm, respectively, i.e. 95% of PPG measurements identified the HR within 8bpm below or 10bpm above the ECG reference. The mean difference between ECG and PPG HR in the AF subgroup (n=10,255 (14.1%)) was 0.9bpm (LLB −8.4bpm; ULB 10.2bpm) and 0.8bpm in the non-AF subgroup (LLB −0.8bpm; ULB 9.6bpm).

Conclusion

The AI algorithm analysing continuous out-of-hospital PPG tracings can annotate heartbeats and assess HR without a clinically significant bias compared to continuous ECG monitoring, both during AF and non-AF rhythms in a heterogenous patient population.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation-Flanders, Strategic Basic Research Fund Correlation plot & Bland-Altman plot

Subclinical synovitis in arthralgia: how often does it result in clinical arthritis? Reflecting on starting points for disease-modifying anti-rheumatic drug treatment

Objectives

According to guidelines, clinical arthritis is mandatory for diagnosing RA. However, in the absence of clinical synovitis, imaging-detected subclinical synovitis is increasingly used instead and is considered as a starting point for DMARD therapy. To search for evidence we studied the natural course of arthralgia patients with subclinical synovitis from three longitudinal cohorts and determined the frequencies of non-progression to clinically apparent inflammatory arthritis (IA) (i.e. ‘false positives’).

Methods

Subclinical synovitis in the hands or feet of arthralgia patients was visualized with US (two cohorts; definition: greyscale ≥2 and/or power Doppler ≥1) or MRI (one cohort; definition: synovitis score ≥1 by two readers). Patients were followed for 1  year on for IA development; two cohorts also had 3  year data. Analyses were stratified for ACPA.

Results

Subclinical synovitis at presentation was present in 36%, 41% and 31% in the three cohorts. Of the ACPA-positive arthralgia patients with subclinical synovitis, 54%, 44% and 68%, respectively, did not develop IA. These percentages were even higher in the ACPA-negative arthralgia patients: 66%, 85% and 89%, respectively. Similar results were seen after 3 years of follow-up.

Conclusion

Replacing clinical arthritis with subclinical synovitis to identify RA introduces a high false-positive rate (44–89%). These data suggest an overestimation regarding the value of ACPA positivity in combination with the presence of subclinical synovitis in patients with arthralgia, which harbours the risk of overtreatment if DMARDs are initiated in the absence of clinical arthritis.

Morning stiffness precedes the development of RA and associates with systemic and subclinical joint inflammation in arthralgia patients

Objectives

Morning stiffness (MS) is characteristic of RA and associates with markers of systemic and local inflammation in RA patients. In patients with arthralgia, MS is a cardinal symptom to recognize arthralgia at-risk for RA development [i.e. clinically suspect arthralgia (CSA)]. In CSA, MS is also assumed to reflect inflammation, but this has never been studied. Therefore we aimed to study whether MS in CSA patients is associated with systemic and subclinical joint inflammation.

Methods

A total of 575 patients presenting with CSA underwent laboratory investigations and contrast-enhanced 1.5 T MRI of the hand and forefoot (scored according to the Rheumatoid Arthritis MRI Score method). Associations of MS (duration ≥60 min) with the presence of subclinical joint inflammation (synovitis, tenosynovitis and osteitis) and increased CRP (≥5 mg/l) were determined with logistic regression. Additionally, the effect of MS duration (≥30, ≥60 and ≥120 min) was studied.

Results

A total of 195 (34%) CSA patients experienced MS. These patients more often had subclinical synovitis [34% vs 21%; odds ratio (OR) 1.95 (95% CI 1.32, 2.87)], subclinical tenosynovitis [36% vs 26%; OR 1.59 (95% CI 1.10, 2.31)] and increased CRP [31% vs 19%; OR 1.93 (95% CI 1.30, 2.88)] than patients without MS. In multivariable analyses, subclinical synovitis [OR 1.77 (95% CI 1.16, 2.69)] and CRP [OR 1.78 (95% CI 1.17–2.69)] remained independently associated with MS. In CSA patients who later developed RA, and thus in retrospect were ‘pre-RA’ at the time of CSA, MS was more strongly associated with subclinical synovitis [OR 2.56 (95% CI 1.04, 6.52)] and CRP [OR 3.86 (95% CI 1.45, 10.24)]. Furthermore, associations increased with longer MS durations.

Conclusion

Inflammation associates with MS in the CSA phase that preceded clinical arthritis. These results increase our understanding of MS when assessing arthralgia in clinical practice.

Determining in which pre-arthritis stage HLA-shared epitope alleles and smoking exert their effect on the development of rheumatoid arthritis

OBJECTIVES

The human leukocyte antigen-shared epitope (HLA-SE) alleles and smoking are the most prominent genetic and environmental risk factors for rheumatoid arthritis (RA). However, at which pre-arthritis stage (asymptomatic/symptomatic) they exert their effect is unknown. We aimed to determine whether HLA-SE and smoking are involved in the onset of autoantibody positivity, symptoms (clinically suspect arthralgia (CSA)) and/or progression to clinical arthritis.

METHODS

We performed meta-analyses on results from the literature on associations of HLA-SE and smoking with anti-citrullinated protein antibodies (ACPAs) in the asymptomatic population. Next, we studied associations of HLA-SE and smoking with autoantibody positivity at CSA onset and with progression to clinical inflammatory arthritis (IA) during follow-up. Associations in ACPA-positive patients with CSA were validated in meta-analyses with other arthralgia cohorts. Analyses were repeated for rheumatoid factor (RF), anti-carbamylated protein antibodies (anti-CarP) and anti-acetylated protein antibodies (AAPA).

RESULTS

Meta-analyses showed that HLA-SE is not associated with ACPA positivity in the asymptomatic population (OR 1.06 (95% CI:0.69 to 1.64)), whereas smoking was associated (OR 1.37 (95% CI: 1.15 to 1.63)). At CSA onset, both HLA-SE and smoking associated with ACPA positivity (OR 2.08 (95% CI: 1.24 to 3.49), OR 2.41 (95% CI: 1.31 to 4.43)). During follow-up, HLA-SE associated with IA development (HR 1.86 (95% CI: 1.23 to 2.82)), in contrast to smoking. This was confirmed in meta-analyses in ACPA-positive arthralgia (HR 1.52 (95% CI: 1.08 to 2.15)). HLA-SE and smoking were not associated with RF, anti-CarP or AAPA-positivity at CSA onset. Longitudinally, AAPA associated with IA development independent from ACPA and RF (HR 1.79 (95% CI: 1.02 to 3.16)), anti-CarP did not.

CONCLUSIONS

HLA-SE and smoking act at different stages: smoking confers risk for ACPA and symptom development, whereas HLA-SE mediates symptom and IA development. These data enhance the understanding of the timing of the key risk factors in the development of RA.

Comparison between 1.5T and 3.0T MRI: both field strengths sensitively detect subclinical inflammation of hand and forefoot in patients with arthralgia

Objective: Magnetic resonance imaging (MRI) of small joints sensitively detects inflammation. This inflammation, and tenosynovitis in particular, has been shown to predict rheumatoid arthritis (RA) development in arthralgia patients. These data have predominantly been acquired on 1.0-1.5 T MRI. However, 3.0 T is now commonly used in practice. Evidence on the comparability of these field strengths is scarce and has never included subtle inflammation in arthralgia patients or tenosynovitis. Therefore, we assessed the comparability of 1.5 T and 3.0 T in detecting subclinical inflammation in arthralgia patients.Method: A total of 2968 locations (joints, bones, tendon sheaths) in the hands and forefeet of 28 patients with small-joint arthralgia, at risk for RA, were imaged on both 1.5 and 3.0 T MRI. Two blinded readers independently scored erosions, osteitis, synovitis, and tenosynovitis, in line with the Rheumatoid Arthritis Magnetic Resonance Imaging Score (RAMRIS). Features were summed into inflammation (osteitis, synovitis, tenosynovitis) and RAMRIS (inflammation and erosions). Agreement was assessed with intraclass correlation coefficients (ICCs) for continuous scores and after dichotomization into presence or absence of inflammation, on patient and location levels.Results: Interreader ICCs were excellent (> 0.90). Comparing 1.5 and 3.0 T revealed an ICC of 0.90 for inflammation and RAMRIS. ICCs for individual inflammation features were: tenosynovitis 0.87 (95% confidence interval 0.74-0.94), synovitis 0.65 (0.24-0.84), and osteitis 0.96 (0.91-0.98). Agreement was 83% for inflammation and 89% for RAMRIS. Analyses on the location level showed similar results.Conclusion: Agreement on subclinical inflammation between 1.5 T and 3.0 T was excellent. Although synovitis scores were slightly different, synovitis often occurs simultaneously with other inflammatory signs, suggesting that scientific results on the predictive value of MRI-detected inflammation for RA, obtained on 1.5 T MRI, can be generalized to 3.0 T MRI.

MRI detected synovitis of the small joints predicts rheumatoid arthritis development in large joint undifferentiated inflammatory arthritis

Objectives

New onset undifferentiated large joint inflammatory arthritis can be diagnostically challenging. It is unknown how often these patients progress to RA, and how they can be identified at first presentation. We assessed clinical and serological features associated with RA development in patients with an undifferentiated mono- or oligo-articular large joint arthritis, and with keen interest in whether an MRI of the small joints of the hand and foot would aid diagnosis.

Methods

Leiden Early Arthritis Clinic includes 4018 patients; this prospective study follows 221 consecutively included patients with new onset undifferentiated large joint arthritis. Baseline clinical data and serology were obtained. Forty-five patients had MRIs (hand and foot). MRIs were scored according to the OMERACT RAMRIS. Univariable and multivariable logistic regression were assessed. Test characteristics, predictive values and net reclassification index (NRI) for RA were determined.

Results

Patients mostly presented with knee or ankle mono-arthritis. During the 12 months’ follow-up 17% developed RA. Autoantibody positivity (ACPA and/or RF) and MRI-detected synovitis in hands and feet were independently associated with RA development in multivariable analyses [odds ratio 10.29 (P = 0.014) and 7.88 (P = 0.017), respectively]. Positive predictive value of autoantibodies, MRI-detected synovitis and combination of both features was 63%, 55% and 100%, respectively. The addition of MRI-detected synovitis to autoantibody status improved diagnostic accuracy (NRI 18.1%).

Conclusion

In patients presenting with undifferentiated large joint arthritis, 17% will develop RA. Autoantibody positivity and subclinical synovitis are independent predictors. The data suggest MRI of small joints is beneficial for early identification of RA in large joint arthritis.

POS0257 TOWARDS A SIMPLIFIED FLUID-SENSITIVE MRI-PROTOCOL IN SMALL JOINTS OF THE HAND IN EARLY ARTHRITIS PATIENTS: RELIABILITY BETWEEN MDIXON AND REGULAR FSE FAT SATURATION MRI-SEQUENCES

Background:

MRI facilitates early recognition of rheumatoid arthritis (RA) by depicting inflammation. Contrast-enhanced T1-weighted and T2-weighted fat-suppressed sequences have been sensitive and thus recommended, but are hampered by invasiveness, costs and long scan time. Therefore we introduced a modified Dixon-sequence (mDixon) which is more patient-friendly, reduces cost, and scan times by 83%. However, it is not known if this mDixon-sequence is reliable in relation to regular MRI-sequences with and without contrast (T1- and T2-weighted, respectively).

Objectives:

We determined the reliability between regular MRI-sequences with and without contrast (T1- and T2-weighted, respectively) and mDixon-MRI in early arthritis patients.

Methods:

29 early arthritis patients underwent regular fat-suppressed-MRI (T1- and T2-weighted) and mDixon-sequences, of metacarpophalangeal-2-5 and wrist-joints. Two readers scored erosions, osteitis, synovitis and tenosynovitis. Intraclass correlation coefficients (ICCs) between readers, and comparing the two sequences, were studied. Spearman correlations were determined.

Results:

Performance between the two readers with the regular-MRI sequences, was good to excellent (ICCs all ≥0.88). The between reader ICC was also good to excellent for the mDixon-MRI (ICCs all ≥0.76). Next, ICCs between the two sequences was investigated to determine the reliability of mDixon. ICCs were good to excellent for total RAMRIS score 0.87 (95%CI 0.74-0.94), for erosions 0.88 (95%CI 0.69-0.95), and total inflammation score 0.84 (95%CI 0.69-0.82). The individual MRI-inflammation scores, had ICCs for osteitis 0.97 (95%CI 0.93-0.98), for tenosynovitis 0.78 (95%CI 0.58-0.89), and for synovitis 0.57 (95%CI 0.26-0.77). In addition, scores were highly correlated for total RAMRIS, erosions, and total MRI-inflammation score (ρ=0.82, ρ=0.81, ρ=0.80, respectively).

Conclusion:

Regular-MRI sequences and mDixon-MRI perform equally well, this suggests that mDixon-sequence is reliable to detect joint inflammation. Thus, this is the first step towards an simplified and abridged MRI-protocol in small hand-joints in early arthritis patients. The ultimate goal will be implementation of this mDixon-MRI sequence. Validation in larger studies is warranted.

Disclosure of Interests:

None declared

POS1391 MEASURING SUBCLINICAL INFLAMMATION IN HAND AND FOREFOOT IN PATIENTS WITH ARTHRALGIA USING 1.5T OR 3.0T MRI: DOES FIELD STRENGTH MATTER?

Background:

Magnetic resonance imaging (MRI) of small joints sensitively detects inflammation. MRI-detected subclinical inflammation, and tenosynovitis in particular, has been shown predictive for RA development in patients with arthralgia. These scientific data are mostly acquired on 1.0T-1.5T MRI scanners. However, 3.0T MRI is nowadays increasingly used in practice. Evidence on the comparability of these field strengths is scarce and it has never been studied in arthralgia where subclinical inflammation is subtle. Moreover, comparisons never included tenosynovitis, which is, of all imaging features, the strongest predictor for progression to RA.

Objectives:

To determine if there is a difference between 1.5T and 3.0T MRI in detecting subclinical inflammation in arthralgia patients.

Methods:

2968 locations (joints, bones or tendon sheaths) in hands and forefeet of 28 arthralgia patients were imaged on both 1.5T and 3.0T MRI. Two independent readers scored for erosions, osteitis, synovitis (according to RAMRIS) and tenosynovitis (as described by Haavaardsholm et al.). Scores were also summed as total inflammation (osteitis, synovitis and tenosynovitis) and total RAMRIS (erosions, osteitis, synovitis and tenosynovitis) scores. Interreader reliability (comparing both readers) and field strength agreement (comparing 1.5T and 3.0T) was assessed with interclass correlation coefficients (ICCs). Next, field strength agreement was assessed after dichotomization into presence or absence of inflammation. Analyses were performed on patient- and location-level.

Results:

ICCs between readers were excellent (>0.90). Comparing 1.5 and 3.0T revealed excellent ICCs of 0.90 (95% confidence interval 0.78-0.95) for the total inflammation score and 0.90 (0.78-0.95) for the total RAMRIS score. ICCs for individual inflammation features were: tenosynovitis: 0.87 (0.74-0.94), synovitis 0.65 (0.24-0.84) and osteitis 0.96 (0.91-0.98). The field strength agreement on dichotomized scores was 83% for the total inflammation score and 89% for the total RAMRIS score. Of the individual features, agreement for tenosynovitis was the highest (89%). Analyses on location- level showed similar results.

Conclusion:

Agreement of subclinical inflammation scores on 1.5T and 3.0T were good to excellent, in particular for tenosynovitis. This suggests that scientific evidence on predictive power of MRI in arthralgia patients, obtained on 1.5T, can be generalized to 3.0T when this field strength would be used for diagnostic purposes in daily practice.

Disclosure of Interests:

None declared

POS0385 DURING DEVELOPMENT OF RHEUMATOID ARTHRITIS, INTERMETATARSAL BURSITIS MAY OCCUR BEFORE CLINICAL JOINT SWELLING: A LARGE MRI STUDY IN PATIENTS WITH CLINICALLY SUSPECT ARTHRALGIA

Background:

Inflammation of the synovial lining is a hallmark of rheumatoid arthritis (RA). A synovial lining is not only present at synovial joints and tendon sheaths but also at bursae. Inflammation of the synovium-lined intermetatarsal bursae in the forefoot, intermetatarsal bursitis (IMB), was recently identified with MRI. It is specific for early RA and present in the majority of RA patients at diagnosis. During development of RA, MRI-detectable subclinical synovitis and tenosynovitis often occur before clinical arthritis presents. Whether IMB is also present in a pre-arthritis stage is unknown.

Objectives:

To assess the occurrence of IMB in patients with clinically suspect arthralgia (CSA) and its association with progression to clinical arthritis in a large MRI-study.

Methods:

We studied 524 consecutive patients presenting with CSA. CSA was defined as recent-onset arthralgia of small joints that is likely to progress to RA based on the clinical expertise of the rheumatologist. Participants underwent unilateral contrast-enhanced 1.5T MRI of the forefoot, metacarpophalangeal (MCP) joints and wrist at baseline. Thereafter patients were followed for detection of clinical arthritis, as identified at physical joint examination by the rheumatologist. Baseline MRIs were evaluated for IMB at all 4 intermetatarsal spaces. Also synovitis, tenosynovitis and osteitis were assessed in line with the RA MRI scoring system (summed as RAMRIS-inflammation). Both IMB and RAMRIS-inflammation were dichotomised into positive/negative using data from age-matched symptom-free controls as a reference. Cox regression analysed the association of IMB with progression to clinical arthritis; multivariable analyses were used to adjust for RAMRIS-inflammation which is known to associate with progression to clinical arthritis. Analyses were repeated stratified for ACPA-status, since ACPA-positive and ACPA-negative RA are considered separate entities with differences in pathophysiology.

Results:

The baseline MRIs showed ≥1 IMB in 35% of CSA-patients. Patients with IMB were more likely to also have synovitis (OR 2.5 (95%CI 1.2–4.9)) and tenosynovitis (8.9 (3.4–22.9)) on forefoot MRI, but not osteitis (0.9 (0.5–1.8)). Patients were followed for median 25 months (IQR 19–27). IMB-positive patients developed clinical arthritis more often than IMB-negative patients (HR 3.0 (1.9-4.8)). This association was independent of RAMRIS-inflammation (adjusted HR 2.2 (1.4–3.6)). In stratified analyses, IMB was more frequent in ACPA-positive than in ACPA-negative CSA (68% vs. 30%, p<0.001). Moreover IMB predicted clinical arthritis development in ACPA-positive CSA (HR 2.5 (1.1–5.7)) but not in ACPA-negative CSA patients (1.0 (0.5–2.2)).

Conclusion:

One-third of CSA patients have IMB. IMB is frequently present in conjunction with subclinical synovitis and tenosynovitis. It precedes the development of clinical arthritis, and in particular the development of ACPA-positive RA. These results reinforce the notion that not only intra- but also juxta-articular synovial inflammation is involved in the development of RA.

Disclosure of Interests:

None declared

Value of imaging detected joint inflammation in explaining fatigue in RA at diagnosis and during the disease course: a large MRI study

OBJECTIVE

Fatigue in rheumatoid arthritis (RA) is hypothesised to be caused by inflammation. Still ~50% of the variance of fatigue in RA cannot be explained by the Disease Activity Score (DAS), nor by background or psychological factors. Since MRI can detect joint inflammation more sensitively than the clinical joint counts as incorporated in the DAS, we hypothesised that inflammation detected by MRI could aid in explaining fatigue in RA at diagnosis and during the follow-up.

METHODS

526 consecutive patients with RA were followed longitudinally. Fatigue was assessed yearly on a Numerical Rating Scale. Hand and foot MRIs were performed at inclusion, after 12 and 24 months in 199 patients and were scored for inflammation (synovitis, tenosynovitis and osteitis combined). We studied whether patients with RA with more MRI-inflammation were more fatigued at diagnosis (linear regression), whether the 2-year course of MRI-inflammation associated with the course of fatigue (linear mixed models) and whether decrease in MRI-inflammation in year 1 associated with subsequent improvement in fatigue in year 2 (cross-lagged models). Similar analyses were done with DAS as inflammation measure.

RESULTS

At diagnosis, higher DAS scores were associated with more severe fatigue (p<0.001). However, patients with more MRI-inflammation were not more fatigued (p=0.94). During 2-year follow-up, DAS decrease associated with improvement in fatigue (p<0.001), but MRI-inflammation decrease did not (p=0.96). DAS decrease in year 1 associated with fatigue improvement in year 2 (p=0.012), as did MRI-inflammation decrease (p=0.039), with similar effect strength.

CONCLUSION

Sensitive measurements of joint inflammation did not explain fatigue in RA at diagnosis and follow-up. This supports the concept that fatigue in RA is partly uncoupled from inflammation.

POS0543 MORNING STIFFNESS IN CLINICALLY SUSPECT ARTHRALGIA IS EXPLAINED BY LOCAL SUBCLINICAL SYNOVITIS AND SYSTEMIC INFLAMMATION

Background:

Morning stiffness (MS) is considered a cardinal symptom in the clinical appraisal of arthralgia patients, suggesting presence of subclinical inflammation, which could indicate an increased chance of progression to rheumatoid arthritis (RA). However, the pathophysiology behind MS in arthralgia patients that is clinically suspect for progressing to RA (clinically suspect arthralgia; CSA) has never been studied. In RA, it is presumed that both and local- and systemic inflammation underlie MS. We therefore hypothesize that, in patients with CSA, MS can also be explained by local- and systemic inflammation.

Objectives:

To determine if MS can be explained by MRI-detected local inflammation (subclinical synovitis and tenosynovitis) and systemic inflammation (C-reactive protein(CRP)).

Methods:

514 CSA patients underwent a contrast-enhanced 1.5T MRI of metacarpophalangeal (MCP) 2-5, wrist and metatarsophalangeal (MTP) 1-5 joints, next to clinical assessment and laboratory investigations. MRIs were scored for synovitis and tenosynovitis in line with the RAMRIS-method. MS was dichotomized as present (duration ≥60 minutes) or absent (duration <60 minutes). Associations of MRI-detected synovitis, tenosynovitis and increased CRP with MS were tested with univariable and multivariable logistic regression. Since earlier research in arthritis patients showed that the effect of combined presence of MRI-detected synovitis and tenosynovitis was increased, compared to the effect of these features separately, interaction between MRI-detected synovitis and tenosynovitis, and between synovitis and increased CRP, was assessed.

Results:

In the studied CSA-patients, mean age was 44 years (sd 13), 397 patients (77%) were female, median tender joint count (TJC-70) was 5 (interquartile range 2-10), and 67 (13%) patients were ACPA-positive. MS was present in 191 (37%) CSA-patients. Baseline characteristics among patients with and without MS were similar. MRI-detected synovitis was more often present in patients with MS compared to patients without MS (34% versus 19%), OR 2.12 (95% CI 1.41-3.19). Also, MRI-detected tenosynovitis was more frequently present in patients with MS (36% versus 24%), OR 1.74 (1.18-2.57). Likewise, increased CRP levels (≥5 mg/L) were more often found in patients with MS (31% versus 18%), OR 2.00 (1.32-3.04). In multivariable analyses, ORs were 1.90 (1.22-2.96) for MRI-detected synovitis and 1.82 (1.18-2.82) for increased CRP. With an OR of 1.20 (0.77-1.87) MRI-detected tenosynovitis was not significantly associated with MS in a multivariable analysis. Interaction between synovitis and tenosynovitis, and between synovitis and CRP was not significant (p-value of 0.13 and 0.15, respectively).

Conclusion:

Presence of MRI-detected synovitis and increased CRP levels are associated with presence of MS in patients with CSA. This indicates that MS in CSA patients could indeed be induced by both local- and systemic inflammation.

Disclosure of Interests:

None declared

POS0356 THE RELATIONSHIP OF GENETICS AND CLINICALLY SUSPECT ARTHRALGIA IN RA DEVELOPMENT ASSESSED USING HC, CSA AND RA PATIENTS

Background:

The identification of a pre-RA stage of patients with clinically suspect arthralgia (CSA) has proven to be beneficial in the early detection of Rheumatoid disease. Similarly, genetic susceptibility studies have identified important genetic risk factors for the development of (CCP positive) RA.1 The question that arises is whether these findings represent independent etiological pathways and could therefore be complimentary in the early diagnosis of RA.

Objectives:

To corroborate the knowledge of genetic differences between HC and RA patients and extend it to include the CSA stage of disease.

Methods:

We used three datasets sampled from the same region in the Netherlands: 1,085 healthy controls (HC), 530 CSA and 1,277 RA patients. CSA patients were monitored for a median of 2 years for conversion into clinically apparent inflammatory arthritis (CSAc) or not (CSAnc).2 We assessed the association between HLA SE and disease stage using logistic regression. The analysis was repeated in the CCP positive and CCP negative strata of both the CSA and the RA populations.

Results:

Consistent with previous studies, HLA SE was significantly enriched in RA patients compared to HC (OR 2.28) (Figure 1). HLA SE also differentiated HC vs CSAc (OR 1.69), CSAnc vs CSAc (OR 1.74), and CSAnc vs RA (0R 2.35). No difference was found in HC vs CSAnc and CSAc vs RA.

Conclusion:

HLA SE is more prevalent in patients who developed (rheumatoid) arthritis than in both healthy controls and CSA patients who do not progress to arthritis. The results presented here seem to indicate a clear distinction between CSA patients who develop arthritis and those who do not. We therefore believe that known RA genetics play a role in the development of arthritis rather than the CSA symptoms. While this relationship varies by CCP status, an independent effect remains. Studies into the broader role of genetics beyond HLA SE are currently underway.

Figure 1.

Distinguishing ability of HLA SE across HC, CSAc, CSAnc and RA in the full populations as well as in the CCP positive and negative stratifications. The arrowhead indicates the “case” status in each logistic regression. OR’s (95% CI) derived from regression coefficients indicate the change in odds ratio attributable to HLA SE positivity.

References:

[1]van der Helm-van Mil, A. H., et al. Arthritis and rheumatism, 2006. 54(4): p. 1117–1121.

[2]van Steenbergen, H.W., et al. Ann Rheum Dis, 2017. 76(3): p. 491-496.

Disclosure of Interests:

None declared

POS0379 DETERMINING IN WHICH PRECLINICAL STAGE HLA-SHARED EPITOPE ALLELES AND SMOKING EXERT THEIR EFFECT IN THE DEVELOPMENT OF RHEUMATOID ARTHRITIS

Background:

The HLA shared epitope (SE) and smoking are the best known genetic and environmental risk factors for rheumatoid arthritis (RA) development; however, at which pre-RA stage they exert their effect is unknown. The following stages are discerned: an asymptomatic stage in which autoimmune responses can develop, a symptomatic stage (clinically suspect arthralgia (CSA)), and development of clinically apparent inflammatory arthritis (IA). Studies in the general asymptomatic population revealed contrasting results on the associations between SE-alleles and smoking and the presence of anti-citrullinated protein antibodies (ACPA). Furthermore, studies on these risk factors in the symptomatic pre-RA phase are scarce and these data might teach us whether SE-alleles and smoking are involved in symptom development and/or progression to clinical arthritis.

Objectives:

We aimed to determine at which pre-RA stage SE and smoking exert their effect. In this respect, the analyses were focused on the presence of ACPA, but associations for other anti-modified protein antibodies (anti-carbamylated and anti-acetylated protein antibodies (anti-CarP and AAPA, respectively)) were also studied.

Methods:

Results from the literature on the association of SE and smoking with ACPA in the asymptomatic population were summarized in inverse-variance weighted meta-analyses. In addition 577 CSA-patients were studied. Associations of SE and smoking with IgG ACPA were studied at baseline (CSA-onset), to assess an effect on symptom development. Additionally, patients were monitored for the development of clinically apparent inflammatory arthritis (IA) for median 2 years and associations of SE, smoking and auto-antibodies with progression to IA were determined. Analyses were stratified for ACPA-status and associations in ACPA-positive patients were validated in meta-analyses with other arthralgia-cohorts. Finally analyses were repeated for anti-CarP and AAPA.

Results:

Meta-analyses showed that SE is not associated with ACPA-positivity in the asymptomatic population (OR 1.06 (95%CI 0.69-1.64)), whereas smoking was associated (OR 1.37 (1.15-1.63)). At CSA-onset, both SE and smoking associated with ACPA-positivity (OR 2.08 (1.24-3.49) and OR 2.41 (1.31-4.43), respectively). During follow-up of CSA-patients SE associated with IA-development (HR 1.86 (1.23-2.82)), in contrast to smoking. SE conferred risk for IA-development in ACPA-negative CSA-patients (HR 1.71 (0.99-2.96)) and in ACPA-positive patients (CSA-cohort HR 1.29 (0.67-2.47); meta-analysis three arthralgia-cohorts HR 1.52 (1.08-2.15)). Investigating the other autoantibodies revealed that SE and smoking were not associated with anti-CarP or AAPA-positivity at CSA-onset; longitudinally AAPA associated with progression to IA independent from ACPA and RF (HR 1.79 (1.02-3.16)), whilst anti-Carp did not.

Conclusion:

SE and smoking act in partly different pre-RA stages. Although SE does not associate with ACPA in the general population, it does mediate symptom-development and further progression to clinical arthritis. Smoking confers risk to development of ACPA and/or joint symptoms, but is not further involved in IA-development. The time-specific biologic pathways that are underlying need further exploration. These data enhance the understanding of the timing of key genetic and environmental risk factors in the trajectory of RA development.

Disclosure of Interests:

None declared

OP0217 IS METACARPOPHALANGEAL-JOINT PAIN AS AN EARLY SYMPTOM OF PATIENTS AT RISK FOR PROGRESSION TO INFLAMMATORY ARTHRITIS EXPLAINED BY MRI-DETECTED SUBCLINICAL INFLAMMATION? – A LARGE OBSERVATIONAL STUDY

Background:

Pain in metacarpophalangeal (MCP)-joints in patients presenting with clinically suspect arthralgia (CSA) is one of the clinical features by which patients are considered at risk for progression to inflammatory arthritis (IA). As such this symptom is characteristic for CSA and therefore part of a list of clinical parameters determined by an EULAR-taskforce to identify a more homogeneous group of patients within CSA (the EULAR definition of arthralgia suspicious for progression to RA). MRI-detected subclinical inflammation is known to be present in patients with CSA. In general, arthralgia in CSA can be explained by this subclinical inflammation, however to date, the association of subclinical inflammation with pain in MCP-joints specifically is not clear. Subsequently, it is unknown whether this association differs pertinently when investigated with self-reported pain, or with pain in the form of tenderness at physical examination.

Objectives:

This study will investigate whether MCP-pain and MCP-joint tenderness are associated with MRI-detected subclinical inflammation in patients with CSA, and more specifically those who have progressed to IA.

Methods:

Between April 2012- February 2019, 602 patients were consecutively included in the Leiden clinically suspect arthralgia (CSA)-cohort. Follow-up ended when patients developed clinically apparent IA (determined at physical examination), or else after 2-years (median follow-up time 25 months). MCP-joints were assessed for self-reported joint pain by the patient using a mannequin and subsequently for joint tenderness by physical examination. Baseline unilateral MRIs of the MCP (2-5)-joints were scored by two readers, blinded for clinical data, on subclinical inflammation (synovitis, tenosynovitis, osteitis). Associations between MCP-pain or MCP-joint tenderness and MRI-detected subclinical inflammation were studied at patient level by logistic regression analyses, entering the mentioned MRI-detected features separately (univariable) and together (multivariable).

Results:

33% of 227 patients with self-reported MCP-pain had MRI-detected subclinical inflammation and 38% of 226 patients with MCP-joint tenderness had MRI-detected subclinical inflammation. Self-reported MCP-joint pain was univariable associated with subclinical inflammation and synovitis in particular (OR 2.00, 95% CI: 1.21-3.30, OR 2.87, 95% CI: 1.29-6.39). In multivariable analysis this MCP-pain was associated with synovitis (OR 2.54, 95% CI: 1.12-5.77). MCP-joint tenderness was univariable associated with subclinical inflammation, and synovitis and tenosynovitis in particular (OR 1.84, 95% CI: 1.29-2.63, OR 1.76, 95% CI: 1.10-2.81, OR 1.69, 95% CI: 1.12-2.55, respectively). In multivariable analysis, tenosynovitis remained significant (OR 1.54, 95% CI: 1.00-2.36). Of all patients with self-reported MCP-joint pain who developed IA, 50% had MRI-detected subclinical inflammation. For MCP-joint tenderness this was 61%. Patients with MCP-joint tenderness without subclinical inflammation who developed IA, developed clinical arthritis at a joint that was not scanned (85%), hence they may have had subclinical inflammation that was not imaged. The other 15% did develop arthritis in an MCP-joint, suggesting that subclinical inflammation developed after CSA-onset.

Conclusion:

Arthralgia in the MCP-joints is associated with subclinical inflammation in CSA, in particular with synovitis and tenosynovitis. The prevalence of subclinical inflammation is highest for tender joints at physical examination; this can be acknowledged when applying the EULAR definition of arthralgia suspicious for progression to RA.

Disclosure of Interests:

None declared

POS0438 IS IMAGING DETECTED JOINT INFLAMMATION HELPFUL IN EXPLAINING FATIGUE IN RHEUMATOID ARTHRITIS AT DIAGNOSIS AND DURING THE DISEASE COURSE? – A LARGE MRI STUDY

Background:

Fatigue in rheumatoid arthritis (RA) is hypothesized to be caused by inflammation. Still ~50% of fatigue in RA cannot be explained by the disease activity score (DAS), nor by generic or psychological factors.

Objectives:

Since MRI can detect joint inflammation more sensitively than DAS, we hypothesized that residual inflammation detected by MRI could aid in explaining fatigue in RA at diagnosis and during follow-up.

Methods:

526 consecutive RA-patients were followed longitudinally. Fatigue was assessed yearly on a numerical rating scale. Hand and foot MRIs were performed at inclusion, after 12 and 24-months in 199 patients and were scored for inflammation (synovitis, tenosynovitis and osteitis combined). We studied whether RA-patients with more MRI-inflammation were more fatigued at diagnosis (linear regression), whether the 2-year course of MRI-inflammation associated with the course of fatigue (linear mixed models) and whether decrease in MRI-inflammation in year-1 associated with subsequent improvement in fatigue in year-2 (cross-lagged models). Similar analyses were done with DAS as inflammation measure.

Results:

At diagnosis, higher DAS-scores were associated with more severe fatigue (p<0.001). However, patients with more MRI-inflammation were not more fatigued (p=0.94). During 2-year follow-up, DAS decrease associated with improvement in fatigue (p<0.001), but MRI-inflammation decrease did not (p=0.96). DAS decrease in year-1 associated with fatigue improvement in year-2 (p=0.012), as did MRI-inflammation decrease (p=0.039), with similar effect strength.

Conclusion:

Sensitive measurements of joint inflammation did not aid in explaining fatigue in RA at diagnosis and follow-up. This supports the concept that fatigue in RA is partly uncoupled from inflammation.

Disclosure of Interests:

None declared

POS0506 TENOSYNOVITIS HAS A HIGH SENSITIVITY FOR EARLY ACPA-POSITIVE AND ACPA-NEGATIVE RA: A LARGE CROSS-SECTIONAL MRI STUDY

Background:

Clinically evident tenosynovitis can be seen in established Rheumatoid arthritis (RA). Imaging research has recently shown that tenosynovitis at small joints occurs in early RA, contributes to typical RA symptoms (including joint swelling) and is infrequent in healthy controls. Imaging-detectable tenosynovitis is often not recognizable at joint examination, hence its prevalence can therefore be underestimated.

Objectives:

We hypothesized that if MRI-detectable tenosynovitis is a true RA-feature, the sensitivity for RA is high, in both ACPA-positive and -negative RA, and lower in other diseases that are associated with enthesitis (such as Spondyloarthritis (SpA) and Psoriatic Arthritis (PsA)). So far, no large MRI-study addressed these questions.

Methods:

Consecutive early arthritis patients (n=1211) from one health-care region underwent contrast-enhanced 1.5T MRI of hand and foot at diagnosis. MRIs were scored for synovitis and tenosynovitis by two readers blinded for clinical data. All included patients with ACPA-positive RA (n=250), ACPA-negative RA (n=282), PsA (n=88), SpA with peripheral arthritis (n=24), reactive arthritis (n=30) and self-limiting undifferentiated arthritis (UA;n=76) were studied. Sensitivity was calculated.

Results:

The sensitivity of tenosynovitis in RA was 85%; 88% for ACPA-positive RA and 82% for and ACPA-negative RA (p=0.19). The sensitivity for RA was significantly higher than for PsA (65%;p=0.001), SpA (53%;p<0.001), reactive arthritis (36%;p<0.001) and self-limiting UA (42%;p<0.001). The observed sensitivity of MRI-synovitis was 91% in RA and ranged 83-54% in the other groups.

Conclusion:

MRI-detected tenosynovitis has a high sensitivity for early ACPA-positive and ACPA-negative RA. This supports both juxta-articular (tenosynovitis) and intra-articular synovial involvement is characteristic for RA.

Figure 1.

Presence of tenosynovitis (in black) in wrist MCPs and MTPs, in rheumatoid arthritis, stratified for ACPA-status and compared to other diseases Legend: RA: Rheumatoïd arthritis; ACPA: anti-citrullinated protein antibodies; UA: undifferentiated arthritis

Disclosure of Interests:

None declared

Tenosynovitis has a high sensitivity for early ACPA-positive and ACPA-negative RA: a large cross-sectional MRI study

OBJECTIVES

Clinically evident tenosynovitis can be seen in established rheumatoid arthritis (RA). Imaging research has recently shown that tenosynovitis at small joints occurs in early RA, contributes to typical RA symptoms (including joint swelling) and is infrequent in healthy controls. Imaging-detectable tenosynovitis is often not recognisable at joint examination, hence its prevalence can therefore be underestimated. We hypothesised that if MRI-detectable tenosynovitis is a true RA feature, the sensitivity for RA is high, in both anti-citrullinated protein antibodies (ACPA)-positive and ACPA-negative RA, and lower in other diseases that are associated with enthesitis (such as spondyloarthritis (SpA) and psoriatic arthritis (PsA)). So far, no large MRI study addressed these questions.

METHODS

Consecutive patients with early arthritis (n=1211) from one healthcare region underwent contrast-enhanced 1.5T MRI of hand and foot at diagnosis. MRIs were scored for synovitis and tenosynovitis by two readers blinded for clinical data. All included patients with ACPA-positive RA (n=250), ACPA-negative RA (n=282), PsA (n=88), peripheral SpA (n=24), reactive arthritis (n=30) and self-limiting undifferentiated arthritis (UA; n=76) were studied. Sensitivity was calculated.

RESULTS

The sensitivity of tenosynovitis in RA was 85%; 88% for ACPA-positive RA and 82% for and ACPA-negative RA (p=0.19). The sensitivity for RA was significantly higher than for PsA (65%; p=0.001), SpA (53%; p<0.001), reactive arthritis (36%; p<0.001) and self-limiting UA (42%; p<0.001). The observed sensitivity of MRI synovitis was 91% in RA and ranged from 83% to 54% in other groups.

CONCLUSIONS

MRI-detected tenosynovitis has a high sensitivity for early ACPA-positive and ACPA-negative RA. This supports that both juxta-articular (tenosynovitis) and intra-articular synovial involvement is characteristic of RA.

Walking disabilities are associated with tenosynovitis at the metatarsophalangeal joints: A longitudinal MRI-study in early arthritis

Objective

The relationship between functional disability and magnetic resonance imaging (MRI) inflammation has been studied for the hands, but has not been well established for the feet, even though walking difficulties are common. Therefore, our objective was to study whether walking difficulties were associated with MRI inflammation at metatarsophalangeal (MTP) joints in early arthritis patients, at diagnosis and during 24 months of follow‐up.

Methods

A total of 532 consecutive patients presenting with early arthritis reported on the presence and severity of walking difficulties (Health Assessment Questionnaire question 4a, scale 0–3), and underwent unilateral contrast‐enhanced MRI of MTP joints 1–5 at baseline. In total, 107 patients had clinical and MRI data at follow‐up (4, 12, and 24 months). MRI inflammation (synovitis, tenosynovitis, and osteitis) was scored in line with the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system. At baseline, the association of walking disability with MRI inflammation was assessed using regression. Longitudinally, the association between a change in walking disability with a change in MRI inflammation was studied with linear mixed models.

Results

At baseline, 81% of patients with walking disabilities had MRI inflammation at MTP joints, versus 68% without walking disabilities (P < 0.001). Total MRI inflammation (i.e., the sum of tenosynovitis, synovitis, and osteitis) was associated with severity of walking disability (β = 0.023, P < 0.001). Studying the MRI features separately, tenosynovitis, synovitis, and osteitis were all univariably associated with severity of walking disability (P < 0.001, P < 0.001, and P = 0.014, respectively). In multivariable analysis, the association was strongest for tenosynovitis. During follow‐up, a decrease in MTP inflammation was associated with a decrease in walking disability (β = 0.029, P = 0.001); in multivariable analyses only, tenosynovitis was independently associated (β = 0.073, P = 0.049).

Conclusion

Of the different inflamed tissues in MTP joints, predominantly MRI‐detected tenosynovitis was associated with walking disabilities. Likewise a reduction in tenosynovitis related to a decrease in walking disabilities. These results increase our understanding of the involvement of tenosynovitis in walking disabilities in early arthritis.

Do magnetic resonance imaging-detected erosions predict progression to rheumatoid arthritis in patients presenting with clinically suspect arthralgia? A longitudinal study

Objective: Radiographic joint erosions are a hallmark of rheumatoid arthritis (RA). Magnetic resonance imaging (MRI) is more sensitive than radiographs in detecting erosions. It is unknown whether MRI-detected erosions are predictive for RA development in patients with clinically suspect arthralgia (CSA). Therefore, we investigated the prognostic value of MRI-detected erosions, defined as any MRI erosion, or MRI erosion characteristics that were recently identified as specific for RA in patients with evident arthritis. Method: Patients presenting with CSA (n = 490) underwent contrast-enhanced 1.5 T MRI of the wrist, metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints. MRIs were scored according to the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system (RAMRIS). Presence of any MRI erosion (present in < 5% of symptom-free controls) and RA-specific erosion characteristics as identified previously (grade ≥ 2 erosions, erosions in MTP5, erosions in MTP1 if aged < 40 years) were studied with clinically apparent inflammatory arthritis development as outcome. Analyses were corrected for age and MRI-detected subclinical inflammation. Results: Erosions were present in 20%. Presence of any MRI erosion was not associated with arthritis development [multivariable analysis hazard ratio (HR) 0.97 (95% confidence interval 0.59-1.59)]. The different RA-specific erosion characteristics were not predictive [grade ≥ 2 HR 1.05 (0.33-3.34), erosions in MTP5 HR 1.08 (0.47-2.48), and MTP1 if aged < 40 years HR 1.11 (0.26-4.70)]. Erosion scores were higher in anti-citrullinated protein antibody (ACPA)-positive than in ACPA-negative patients (median 2.0 vs 1.0, p = 0.002), and related to more subclinical inflammation. Within both subgroups, MRI erosions were not predictive. Conclusions: MRI-detected erosions in hands and feet were not predictive for inflammatory arthritis development. Therefore, evaluating MRI for erosions in addition to subclinical inflammation does not provide added clinical value in CSA.

Improving the feasibility of MRI in clinically suspect arthralgia for prediction of rheumatoid arthritis by omitting scanning of the feet

OBJECTIVES

The use of MR-imaging is recommended for the early detection of RA. Next to the small joints of the hands, foot-joints are often involved. Therefore, imaging inflammation of the feet in addition to hands may be informative, but prolongs scan-time and leads to additional costs. We studied the value of MRI of the feet alone and complementary to MRI of the hands in patients with clinically suspect arthralgia (CSA).

METHODS

357 consecutively included CSA patients underwent contrast-enhanced 1.5 T-MRI of hand (MCP2-5 and wrist) and foot (MTP1-5) joints at baseline. Scans were scored for synovitis, osteitis and tenosynovitis. After ⩾1 year follow-up, the development of clinically apparent inflammatory arthritis (IA) was studied. Cox regression was performed and test characteristics were evaluated. Sensitivity analyses were performed for the outcome RA-development (2010-criteria).

RESULTS

MRI-detected tenosynovitis of the feet was associated with IA-development, independently from synovitis and osteitis hazard ratio (HR) (95%CI) 4.75 (2.38; 9.49), and independently from ACPA and CRP, HR 3.13 (1.48; 6.64). From all CSA patients, 11% had inflammation in hands and feet, 29% only in hands and 3% only in feet. In line with this finding, the addition of MRI-feet to MRI-hands did not increase the predictive accuracy; the sensitivity remained 77%, while the specificity decreased from 66% to 62%. Sensitivity analyses with RA development as outcome showed similar results.

CONCLUSION

Tenosynovitis at the forefeet in CSA predicted IA and RA development. Addition of foot MRI to hand MRI did not increase the accuracy. Foot MRI can be omitted to reduce scan time and costs and increase the feasibility.

AB1258 THE VALUE OF THE SQUEEZE TEST FOR DETECTION OF SUBCLINICAL SYNOVITIS IN PATIENTS WITH ARTHRALGIA SUSPICIOUS FOR PROGRESSION TO RA

Background:

The squeeze test (or compression test) is often used to quickly screen for arthritis in metacarpophalangeal (MCP)- and metatarsophalangeal (MTP)-joints. A positive test is traditionally assumed to indicate presence of synovitis. Previous studies in early arthritis indeed showed that a positive squeeze test was associated with presence of swollen MCP- and MTP-joints, as well as with local MRI-detected inflammation. The sensitivity of the test, with MRI-detected synovitis as reference, was 31-33%. The field is moving towards identifying patients at risk for rheumatoid arthritis (RA) in the phase of arthralgia. However, it is unclear if the squeeze test in the phase of clinically suspect arthralgia (CSA) is associated with subclinical inflammation, which can be detected with MRI.

Objectives:

We aimed to assess if a positive squeeze test in patients with CSA is associated with MRI-detected subclinical inflammation, especially with subclinical synovitis and tenosynovitis (the latter is recently identified as a strong predictor for RA-development).

Methods:

315 patients with recent-onset (<1 year) arthralgia of small joints and a clinical suspicion for progression to RA were consecutively included in our CSA-cohort. At baseline the squeeze test (compression across the knuckles of MCP- and MTP-joints with the force of a firm handshake) and unilateral contrast-enhanced 1.5T MRI of MCP(2-5)- and MTP(1-5)-joints was performed and scored according to RAMRIS. MRI-scores were dichotomized with data from age-matched symptom-free controls as reference. Follow-up ended when patients developed clinically apparent inflammatory arthritis (IA), or else after 2 years. Associations of the squeeze test and MRI-data were studied with generalized estimating equations, associations with IA-development with cox regression.

Results:

51% of CSA-patients had a positive squeeze test in MCP- or MTP-joints. In univariable analyses a positive test was associated with MRI-detected subclinical synovitis (OR 2.10 (95%CI 1.30-3.40)) and tenosynovitis (OR 1.68 (1.05-2.68)). In multivariable analyses including both inflammatory features only synovitis remained significant (OR 1.90 (1.16-3.13)). Thus, a positive squeeze test is a measure of subclinical synovitis, with a sensitivity of 44% (95%CI 33-55) and specificity of 72% (68-76).

A positive squeeze test in CSA was not associated with IA-development in cox regression adjusted for age, gender, CRP and ACPA-status (HR 1.57 (0.77-3.19). This was consistent with the finding that subclinical synovitis was not associated with IA-development in multivariable analysis adjusted for age, gender, CRP, ACPA-status and tenosynovitis (HR 1.40 (0.59-3.31), whilst tenosynovitis was associated (HR 4.94 (2.03-12.06).

Conclusion:

The squeeze test is a simple test that, when positive in CSA, doubles the probability of presence of subclinical synovitis.

Disclosure of Interests:

None declared

SAT0071 SUBCLINICAL SYNOVITIS IN ARTHRALGIA: HOW OFTEN DOES IT RESULT IN CLINICAL ARTHRITIS? A LONGITUDINAL STUDY TO REFLECT ON STARTING POINTS FOR DMARD TREATMENT

Background:

Clinically apparent arthritis is mandatory for diagnosing and classifying RA. It is often used as endpoint in arthralgia cohorts and as a starting point for DMARD therapy in clinical practice. In recent literature subclinical synovitis, visualized with MRI or ultrasound, is increasingly used as a starting point for DMARD therapy in absence of clinically apparent arthritis. However, not all patients with a subclinical synovitis will develop clinically apparent arthritis, and thus may be overtreated. It has even been suggested to replace the entry-criterion of clinical arthritis by subclinical synovitis within the 2010 classification criteria for RA to diminish overtreatment. However this might lead to an overclassification of the disease. Because of aforementioned reasoning we aimed to evaluate the risk of overtreatment of these approaches and therefore performed a longitudinal study in three observational arthralgia cohorts.

Objectives:

To determine the frequency of non-progression to clinical arthritis in patients with subclinical synovitis, also after considering the 2010-criteria.

Methods:

Three individual cohorts of arthralgia patients without clinically apparent arthritis (n=166, 473 and 168) were followed for 1-year on the development of inflammatory arthritis (IA). At baseline subclinical synovitis in hands or feet was visualized with ultrasound (US) (defined as greyscale≥2 and/or power-doppler≥1) in cohort 1 and 3 and MRI (synovitis score ≥1 by two readers) in cohort 2. For all patients with subclinical synovitis the proportion of progressors (‘true positives’) and non-progressors (‘false positives’) were determined. The same analysis was done in the subgroup of patients that fulfilled the 2010 criteria for RA, if subclinical synovitis was used as entry criterion. Analyses were stratified for ACPA.

Results:

At baseline 36%, 41% and 31% of patients had subclinical synovitis. Of the ACPA-positive arthralgia patients with subclinical synovitis 46%, 56% and 29% respectively developed IA, whereas 54%, 44% and 71% did not progress. Within ACPA-negative arthralgia patients with subclinical synovitis 34%, 15% and 10% developed IA; whereas 66%, 85% and 90% did not progress (Figure 1A). Similar results were seen in the subgroup of patients that fulfilled the 2010 criteria with subclinical synovitis as entry criterion (Figure 1B).

Figure 1.

Percentage of arthralgia patients with subclinical synovitis that did and did not develop IA, in three independent cohorts:(A) Percentage of patients with subclinical synovitis that did and did not progress to IA after one-year follow-up, stratified for ACPA status. (B) Percentage of patients with subclinical synovitis and ≥6 points at baseline that did and did not progress to IA after one-year follow-up stratified for ACPA status.

Conclusion:

Replacing clinical arthritis by subclinical synovitis in arthralgia introduces a high false-positive rate: 44-71% (ACPA-pos) and 66-90% (ACPA-neg) of patients with subclinical synovitis did not develop clinically apparent arthritis within one year. Applying the 2010-criteria in this setting did not diminish the false positive rate. Starting DMARDs in patients without clinical synovitis may therefore introduce considerable overtreatment.

Acknowledgments *:

C Rogier and F Wouters contributed equal to this study

Disclosure of Interests:

None declared

FRI0542 OBTAINING HIGH POSITIVE PREDICTIVE VALUES FOR THE DEVELOPMENT OF CLINICALLY APPARENT ARTHRITIS IN PATIENTS PRESENTING WITH CLINICALLY SUSPECT ARTHRALGIA; IS IT FEASIBLE?

Background:

The hypothesis that initiation of DMARD-treatment before arthritis becomes apparent could permanently modulate the disease process, such that persistent RA is prevented, is being studied in several ongoing trials. Essential for such studies is the ability to accurately predict clinically apparent inflammatory arthritis (IA). However there are two hurdles: first, it is insufficiently known whether it is possible to obtain high positive predictive values (PPV) in patients presenting with clinically suspect arthralgia (CSA). Second, none of current predictive models is validated in independent cohorts. We here aimed to evaluate the first question, incorporating improved markers of MRI-detected subclinical inflammation that were recently identified but have not yet been combined with other known predictors.[1]

Objectives:

To assess the feasibility of achieving high PPVs in prediction of IA-development in patients with CSA by combining clinical, laboratory and imaging parameters.

Methods:

580 patients with CSA were consecutively included in the Clinically Suspect Arthralgia (CSA)-cohort and followed on the development of IA, determined by physical examination of joints. Unilateral contrast-enhanced 1.5 Tesla MRIs were made of MCP(2-5), wrist and MTP(1-5)-joints at baseline and scored in line with the RAMRIS. The number of locations with subclinical inflammation (0/1-2/≥3) and the presence of MCP peritendinitis were defined as described previously.[1] Other studied clinical and laboratory variables were based on the literature: initial localisation of complaints (small/large joints), functional disability (health assessment questionnaire (HAQ) ≥1), ACPA-positivity (Anti-CCP2), RF-positivity (IgM-RF) and elevated CRP.[2,3] LASSO Cox regression with a 10-fold cross-validated shrinkage parameter was used for predictor selection. Regression coefficients were rounded to the nearest number ending in .5 or .0 and multiplied by two, resulting in a weighted score. Kaplan Meijer curves were used to obtain PPVs of this weighted score and the area under the curve (AUC) was determined at 2-year follow-up.

Results:

Mean age was 44, 78% was female, and 18% progressed to IA within 2 years. The following parameters were selected with LASSO: RF-positivity, ACPA-positivity, HAQ≥1, >2 locations of subclinical inflammation and presence of MCP-extensor peritendinitis. Based on the beta of LASSO-regression, patients were assigned 2 points for the risk-factors ACPA-positivity and >2 locations of subclinical inflammation, 1 point for RF-positivity and presence of MCP-extensor peritendinitis and 0 points for HAQ≥1. Kaplan Meijer curves show PPVs of 8%, 9%, 30%, 54%, 73%, 79% and 86% at two years (Figure 1). This model yielded an AUC of 0.79.

Figure 1.

Kaplan Meijer curves on inflammatory arthritis development stratified for number of points based on LASSO regression. Legend: Points were based on the regression coefficients yielded by Cox LASSO-regression. 2 points were assigned for the risk factors ACPA-positivity and >2 locations of subclinical inflammation and 1 point was assigned for RF-positivity and presence of MCP-extensor peritendinitis.

Conclusion:

High PPVs for IA-development can be achieved in patients with CSA by weighting a combination of known predictors. Although encouraging, these data are based on one observational cohort study and have not been validated in independent cohorts, limiting the relevance. To support future research in the field of arthralgia, it is needed that different research groups work together to come to risk estimations that are validated and accepted.

References:

[1] Matthijssen XME et al. ART 2019;21(1):249-.

[2] van Steenbergen HW et al. ART 2014;16(2):R92.

[3] ten Brinck RM et al. RMD Open 2017;3(1):e000419.

Disclosure of Interests:

None declared

THU0064 ANTIBODY-RESPONSE MATURATION IN THE PHASE OF CLINICALLY SUSPECT ARTHRALGIA AND ITS RELATION WITH PROGRESSION TO RHEUMATOID ARTHRITIS

Background:

Auto-antibodies in rheumatoid arthritis (RA) are often present years before disease onset but their mere presence does not seem enough to induce RA. Because several nested-case control studies have shown that autoantibody-response maturation precedes disease onset, it is suggested that it plays a role in disease triggering. At present, it is undetermined whether autoantibody-response maturation occurs in the symptomatic phase preceding clinical arthritis (i.e. Clinically Suspect Arthralgia, CSA), or whether it occurs even earlier in the asymptomatic phase. Secondly, if autoantibody-response maturation is a final step towards clinical disease development, maturation is expected to be present in the patients that progress from CSA to RA, but not in CSA-patients that do not progress.

Objectives:

To better understand the timeframe of autoantibody-response maturation and its relation to development of RA, we investigated autoantibody-response maturation in patients with CSA that did and did not progress to clinically apparent inflammatory arthritis (IA).

Methods:

In serum from 148 CSA-patients, we determined the presence and levels of three autoantibodies (ACPA, anti-CarP and AAPA), with three isotypes each (IgM, IgG, IgA), resulting in 9 autoantibody measurements per patient per time-point. Measurements were performed on sera obtained at first presentation at the outpatient clinic and when patients developed IA or else after two years. In-house ELISA was used for all measurements. Three analyses were performed, in patients that progressed to IA (n=56) and in patients that did not progress (n=92) separately. First, in patients negative for all measurements at baseline, we determined the frequency of conversion to seropositivity. Second, in patients with at least one positive test at baseline, we studied the frequency of autoantibody positivity over time. Finally, we determined the change in autoantibody levels in patients positive for the respective autoantibodies at baseline. Frequencies and medians were reported. Statistical significance was tested with Fisher’s Exact test and GEE, taking into account that measurements within one autoantibody type (ACPA, anti-CarP or AAPA) can be correlated.

Results:

First we studied patients negative for all antibodies at baseline (54% of patients that progressed to IA and 76% of patients that did not progress). 17% of patients that progressed to IA became positive over time, compared to 6% of the patients that did not develop IA (p=0.12). Then we studied patients in whom at least one autoantibody was present at baseline and evaluated autoantibody-positivity over time. In patients that progressed to IA, the number of autoantibodies detected at baseline did not change significantly during follow-up (median 1.5 (IQR 1-3, max. 6) to 1.0 (IQR 1-4, max. 6) (p=0.18)). In the patients with CSA that did not progress similar findings were made (1.0 (IQR 1-2, max. 4) at baseline and 1.0 (IQR 0-2, max. 5) after 2-years (p=0.07)). Increase in number of positive measurements over time took place in only few patients: in 15% of the patients that progressed to IA and in 18% from those that did not progress (p=1.00). Likewise, autoantibody levels did not significantly change over time, both in patients that progressed and in patients that did not progress.

Conclusion:

The presence of IgM, IgG and IgA ACPA, anti-CarP and AAPA, as well as autoantibody levels, did not significantly increase over time in patients with CSA; this was similar for patients that did and did not develop clinical arthritis. These findings suggest that antibody-response maturation occurs before presenting with symptoms and also that broadening of the autoantibody response is not specific for progression from arthralgia to RA.

Disclosure of Interests:

None declared

A search to the target tissue in which RA-specific inflammation starts: a detailed MRI study to improve identification of RA-specific features in the phase of clinically suspect arthralgia

OBJECTIVE

Based on a unique cohort of clinically suspect arthralgia (CSA) patients, we analysed which combinations of MRI features at onset were predictive for rheumatoid arthritis (RA) development. This was done to increase our comprehension of locations of RA onset and improve the predictive accuracy of MRI in CSA.

METHODS

In the discovery cohort, 225 CSA patients were followed on clinical arthritis development. Contrast-enhanced 1.5 T MRIs were made of unilateral metacarpophalangeal (MCP) (2-5), wrist, and metatarsophalangeal (1-5) joints at baseline and scored for synovitis, tenosynovitis, and bone marrow edema. Severity, number, and combinations of locations (joint/tendon/bone) with subclinical inflammation were determined, with symptom-free controls of similar age category as reference. Cox regression was used for predictor selection. Predictive values were determined at 1 year follow-up. Results were validated in 209 CSA patients.

RESULTS

In both cohorts, 15% developed arthritis < 1 year. The multivariable Cox model selected presence of MCP-extensor peritendinitis (HR 4.38 (2.07-9.25)) and the number of locations with subclinical inflammation (1-2 locations HR 2.54 (1.11-5.82); ≥ 3 locations HR 3.75 (1.49-9.48)) as predictors. Severity and combinations of inflammatory lesions were not selected. Based on these variables, five risk categories were defined: no subclinical inflammation, 1-2 locations, or ≥ 3 locations, with or without MCP-extensor peritendinitis. Positive predictive values (PPVs) ranged 5% (lowest category; NPV 95%) to 67% (highest category). Similar findings were obtained in the validation cohort; PPVs ranged 4% (lowest category; NPV 96%) to 63% (highest category).

CONCLUSION

Tenosynovitis, particularly MCP-extensor peritendinitis, is among the first tissues affected by RA. Incorporating this feature and number of locations with subclinical inflammation improved prediction making with PPVs up to 63-67%.

The effect of Activin-A on periodontal ligament fibroblasts-mediated osteoclast formation in healthy donors and in patients with fibrodysplasia ossificans progressiva

Fibrodysplasia ossificans progressiva (FOP) is a genetic disease characterized by heterotopic ossification (HO). The disease is caused by a mutation in the activin receptor type 1 (ACVR1) gene that enhances this receptor's responsiveness to Activin‐A. Binding of Activin‐A to the mutated ACVR1 receptor induces osteogenic differentiation. Whether Activin‐A also affects osteoclast formation in FOP is not known. Therefore we investigated its effect on the osteoclastogenesis‐inducing potential of periodontal ligament fibroblasts (PLF) from teeth of healthy controls and patients with FOP. We used western blot analysis of phosphorylated SMAD3 (pSMAD3) and quantitative polymerase chain reaction to assess the effect of Activin‐A on the PLF. PLF‐induced osteoclast formation and gene expression were studied by coculturing control and FOP PLF with CD14‐positive osteoclast precursor cells from healthy donors. Osteoclast formation was also assessed in control CD14 cultures stimulated by macrophage colony‐stimulating factor (M‐CSF) and receptor activator of nuclear factor kappa‐B ligand (RANK‐L). Although Activin‐A increased activation of the pSMAD3 pathway in both control and FOP PLF, it increased ACVR1, FK binding protein 12 (FKBP12), an inhibitor of DNA binding 1 protein (ID‐1) expression only in FOP PLF. Activin‐A inhibited PLF mediated osteoclast formation albeit only significantly when induced by FOP PLF. In these cocultures, it reduced M‐CSF and dendritic cell‐specific transmembrane protein (DC‐STAMP) expression. Activin‐A also inhibited osteoclast formation in M‐CSF and RANK‐L mediated monocultures of CD14+ cells by inhibiting their proliferation.

This study brings new insight on the role of Activin A in osteoclast formation, which may further add to understanding FOP pathophysiology; in addition to the known Activin‐A‐mediated HO, this study shows that Activin‐A may also inhibit osteoclast formation, thereby further promoting HO formation.

Osteogenic and osteoclastogenic potential of jaw bone-derived cells-A case study

Though the stem cell properties of tooth-derived periodontal ligament and gingival cells have been widely documented, surprisingly little is known about both the osteogenic and osteoclastogenic differentiation capacities of the more clinically relevant jaw bone-derived cells. These cells could be considered being recruited during bone healing such as after tooth extraction, after placing an implant, or after surgical or traumatic injury. Here, we compared the osteoblast and osteoclastogenesis features of four consecutive bone outgrowths with periodontal ligament and gingiva cells. For osteogenesis assay, cells were cultured in osteogenic medium, whereas in osteoclastogenesis assays, cells were cultured in the presence of human peripheral blood mononuclear cells (PBMCs) as a source of osteoclast precursors. After osteogenic stimulus, all six cell types responded by an increased expression of osteoblast markers RUNX2 and DMP1. Periodontal ligament cells expressed significantly higher levels of RUNX2 compared to all bone outgrowths. Alkaline phosphatase enzyme levels in periodontal ligament cells reached earlier and higher peak expression. Mineral deposits were highest in periodontal ligament, gingiva and the first bone outgrowth. Osteoclastogenesis revealed a stepwise increase of secreted pro-osteoclastogenesis proteins M-CSF, IL-1β, and TNF-α in the last three consecutive bone cultures. OPG mRNA showed the opposite: high expression in periodontal and gingiva cells and the first outgrowth. Osteoclast numbers were similar between the six cultures, both on bone and on plastic. This first study reveals that jaw bone outgrowths contain bone remodelling features that are slightly different from tooth-associated cells.

Undifferentiated carcinoma of the pancreas in a cockatiel ( Nymphicus hollandicus ): case report

ABSTRACT Undifferentiated carcinoma of the pancreas is a malignant neoplasm that is uncommon among domestic species, especially cockatiels (Nymphicus hollandicus), one of the most popular birds kept as a pet throughout the world. The aim of this study was to describe the occurrence of an undifferentiated carcinoma in the pancreas of a cockatiel. A bird, an adult male that died naturally with swelling in the abdominal region, was referred to necropsy. Macroscopic examination showed poor body condition, the coelomic cavity filled with liquid and a white mass attached to the pancreas and other smaller masses attached to the duodenum. Tissue samples and organs were harvested and fixed in 10% buffered formalin, then routinely processed for histopathology and stained with hematoxylin and eosin. Microscopic analysis demonstrated an epithelial neoplasia with a predominantly solid pattern, lymphatic invasion and involvement of the intestinal serous membrane. These findings indicate the occurrence of an undifferentiated pancreatic carcinoma in a cockatiel that was diagnosed by histopathology.

Pneumotoxicosis in Sheep Caused by Ingestion of Trema Micrantha

Trema micrantha, a fast-growing tree distributed throughout the Americas, produces palatable leaves that have been associated with hepatic necrosis and acute death when consumed by livestock. This report describes fatal pulmonary disease of sheep triggered by consumption of Trema micrantha. Affected sheep had severe progressive dyspnea for a few days before death. Subcutaneous and mediastinal emphysema, reddened lungs, interalveolar septal thickening, and diffuse type II pneumocyte proliferation were the main pathological findings. After ingesting 77.5 and 102.5 g/kg (divided in 3 doses, at 30-day intervals) of T. micrantha leaves, 2 additional sheep developed the same condition. These findings indicate that T. micrantha toxicosis should be considered in the differential diagnosis of ovine respiratory disease.

168 INFLUENCE OF SEVERAL INSULIN PLASMA CONCENTRATIONS ON PROGESTERONE PRODUCTION AND HISTOLOGY OF CORPORA LUTEA IN SUPEROVULATED EWES

Nutritional status is essential for the determination of mammalian reproductive performance, and insulin is one of the main indicators for such condition. This hormone is able to interfere, directly or indirectly, with CL function, leading to alterations in steroidogenic capacity and cell development and, consequently, early embryonic development. The aim of this work was to identify CL histological alterations caused by different insulin plasma concentrations in superovulated ewes, as well as their interference in CL progesterone production. Santa Inês ewes (n = 24, 4 years old) were divided into 3 treatments: control (T1, n = 9); hypoinsulinemic (T2, n = 6), and hyperinsulinemic (T3, n = 9). In order to become hypoinsulinemic, ewes were treated with a single dose of alloxan monohydrate (50 mg kg-1 i.v; Sigma-Aldich, St. Louis, MO, USA) 48 h before the beginning of the superovulation protocol, whereas the hyperinsulinemic group was treated with administrations of 20 IU of NPH human insulin at every 12 h (Biolin-N; BIOBRAS, Montes Claros, Brazil). All animals were fed corn silage and minerals ad libitum. Animals had their estrus synchronized with vaginal pessaries containing medroxyprogesterone acetate (60 mg) and were superovulated with porcine FSH (250 IU, PLUSET®, Calier, Spain) and eCG (250 IU, Novormon®, Schering-Plough, Kenilworth, NJ, USA), in a 13-day protocol. After removal of vaginal pessaries, blood samples used for quantification of progesterone and plasmatic insulin by radioimmunoassay were collected daily at 0700 h until the day before embryo recovery. Hysterectomy was performed in all groups after embryo recovery (T1: n = 3, T2: n = 6, and T3: n = 4), and ovaries were placed in buffered formalin saline. CL histological sections were evaluated by hematoxylin/eosin staining. Results were assessed by SAS statistical analysis software, using the MIXED procedure (SAS Institute Inc., Cary, NC, USA). Mean values were compared by Tukey’s test. The mean CL number was lower in T2 (5.0 ± 2.7; P < 0.05) compared with T1 (10.2 ± 5.1) and T3 (11.3 ± 3.0) animals. No histological differences were observed between treatments T1 and T3. However, CL within the T2 group had a higher number of cells with picnotic nuclei and strongly contracted eosinophilic cytoplasm. Such alterations are suggestive of cellular apoptosis. The T2 group also differed for P4 production (P < 0.01) from the second (T2: 2.23 ± 0.71 ηg mL-1; T1: 5.42 ± 4.01 ηg mL-1; T3: 6.44 ± 2.76 ηg mL-1) to the sixth day post-estrus (T2: 7.58 ± 7.00; T1: 24.79 ± 8.40; T3: 32.07 ± 0.85 ηg mL-1). The mean insulin plasma concentration differed between treatments (P < 0.01); higher concentrations were obtained in the T3 group (20.05 ± 7.50 μIU mL-1), whereas the T2 group had lower concentrations (10.18 ± 3.57 μIU mL-1) compared to controls (T1: 14.52 ± 3.80 μIU mL-1). In conclusion, low plasma concentration of insulin may restrict the response to superovulatory treatment and cause CL histological changes, suggesting a reduction in cell activity due to premature cellular senescence.

All-solid-state lock-in imaging for wide-field fluorescence lifetime sensing

Fluorescence Lifetime Imaging Microscopy (FLIM) is a powerful technique that is increasingly being used in the life sciences during the past decades. However, a broader application of FLIM requires more cost-effective and user-friendly solutions. We demonstrate the use of a simple CCD/CMOS lock-in imager for fluorescence lifetime detection. The SwissRanger SR-2 time-of-flight detector, originally developed for 3D vision, embeds all the functionalities required for FLIM in a compact system. The further development of this technology and its combination with light-emitting-and laser diodes could drive a wider spreading of thuse of FLIM including high-throughput applications.