Patients with seronegative rheumatoid arthritis have a different phenotype than seropositive patients: A clinical and ultrasound study

Introduction

Rheumatoid arthritis (RA) is an inflammatory disease whose clinical phenotype largely depends on the presence of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA). Seronegative RA appears to be a less severe disease, but this remains controversial. This study aimed to assess whether seronegative patients show a less severe disease than seropositive patients.

Methods

A cross-sectional study was conducted on RA outpatients from a single center. Clinical activity scales, laboratory evaluations, and cardiovascular risk scores were assessed. Musculoskeletal ultrasound (US) examinations were performed.

Results

One hundred and fourteen patients were enrolled. Eighty-five were seropositive (76% women) and 29 seronegative (93% women). Seropositive patients had a younger age at disease onset (43 ± 14 vs. 54 ± 11; p = 0.001) and used sulfasalazine (47 vs. 17%; p = 0.004) and glucocorticoids (36 vs. 10%; p = 0.007) more frequently. No differences in clinical activity scales and in 10-year cardiovascular risk were observed. Pathological US data were found more frequently in seropositive patients in the 2^nd metacarpophalangeal (MCP) joint, both in grayscale (71 vs. 38%; p = 0.008) and in power Doppler (PD; 53 vs. 9%; p < 0.001); erosions (36 vs. 9%; p = 0.020) were also more frequent. We found greater severity of PD signals in the 2nd MCP and 3rd MCP joints of the seropositive patients, while synovitis severity was higher only in the 2nd MCP joints. The percentage of total joints with erosions (9 vs. 1%; p < 0.001) and 2nd MCP joints with erosions (25 vs. 7%; p < 0.001) was higher in seropositive patients.

Conclusion

RA patients show a differentiated phenotype according to their ACPA and RF status. In seronegative patients, RA begins later in life and has a lower requirement for antirheumatic therapies. On US evaluation, seropositive patients show more joint damage, especially in MCP joints. Despite this, long-term cardiovascular risk is similar among RA patients, regardless of their RF and ACPA status.

Metabolic Reprogramming in SARS-CoV-2 Infection Impacts the Outcome of COVID-19 Patients

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection triggers inflammatory clinical stages that affect the outcome of patients with coronavirus disease 2019 (COVID-19). Disease severity may be associated with a metabolic imbalance related to amino acids, lipids, and energy-generating pathways. The aim of this study was to characterize the profile of amino acids and acylcarnitines in COVID-19 patients. A multicenter, cross-sectional study was carried out. A total of 453 individuals were classified by disease severity. Levels of 11 amino acids, 31 acylcarnitines, and succinylacetone in serum samples were analyzed by electrospray ionization-triple quadrupole tandem mass spectrometry. Different clusters were observed in partial least squares discriminant analysis, with phenylalanine, alanine, citrulline, proline, and succinylacetone providing the major contribution to the variability in each cluster (variable importance in the projection >1.5). In logistic models adjusted by age, sex, type 2 diabetes mellitus, hypertension, and nutritional status, phenylalanine was associated with critical outcomes (odds ratio=5.3 (95% CI 3.16-9.2) in the severe vs. critical model, with an area under the curve of 0.84 (95% CI 0.77-0.90). In conclusion the metabolic imbalance in COVID-19 patients might affect disease progression. This work shows an association of phenylalanine with critical outcomes in COVID-19 patients, highlighting phenylalanine as a potential metabolic biomarker of disease severity.

OP0168 DEVELOPMENT OF AN ULTRASOUND SCORING SYSTEM FOR CPPD EXTENT: RESULTS FROM A DELPHI PROCESS AND WEB-RELIABILITY EXERCISE BY THE OMERACT US WORKING GROUP

Background

Ultrasound (US) has proven to be an excellent imaging technique for detecting calcium pyrophosphate (CPP) deposition disease (CPPD); it is also widely available and inexpensive and can be performed during the clinic visit making it the preferred imaging modality for many rheumatologists. However, no validated grading systems have yet been developed allowing for a quantification of the extent of crystal deposition in CPPD.

Objectives

The aim of this study was to develop a scoring system for the quantification of CPP deposition at a patient level according to the OMERACT framework.

Methods

As part of the OMERACT methodology, we performed a systematic literature review (SLR) and meta-analysis aimed to estimate the prevalence of CPP deposition in peripheral joints by imaging, in order to identify relevant joints for CPPD monitoring. A preliminary survey was also circulated among the members of the OMERACT US – CPPD working group to collect their own suggestions according to their personal experience. Subsequently, a Delphi survey was prepared and circulated between members of the group, including statements that reflected both the results of the SLR and of the preliminary survey. In total, 32 statements were generated regarding the type of scoring for single structures, the sites to be included, the final scoring at patient level, and the scanning technique. Participants were asked to reply on a 5-point Likert scale (1, strongly disagree to 5, strongly agree) and agreement was achieved when 4 and 5 grades reached 75% or more of concordance. In case of disagreement, new statements were proposed according to the members’ suggestions and circulated for voting in a subsequent round. After agreement of a scoring system, the validation process began. Two rounds of a web-based exercise on static images were conducted on 120 images representing equally all sites under investigation and all degrees of crystal deposition, to assess the intra- and inter-reader reliability of the new scoring system. Representative images of the scoring system were visible throughout the entire exercise in order to facilitate the scoring of the lesions.

Results

Three Delphi rounds were needed to reach agreement on all items. 32/41 members of the OMERACT US-CPPD working group replied in the first round, 26/32 in the second, and 25/26 in the third round. Twenty statements were approved in the first round, 3 in the second, and 3 in the third round. Only the knees (menisci and hyaline cartilage) and the triangular fibrocartilage of the wrist were included in the final score, using a four-grade system (0-3). It was decided that each anatomical structure should be scored separately and then also summed in order to define the joint score. The sum of the assessed joints was the total score at patient level. The final scoring system with the definitions and the relative technical notes is represented in Figure 1. 33/41 members participated to the reliability exercise. The inter-reader reliability of the scoring was substantial (kappa of 0.72), and the intra-reader reliability was almost perfect (kappa of 0.82).

Conclusion

This is the first study for developing a scoring system for the extent of CPP crystal deposition in patients with CPPD. The scoring system demonstrated to be reliable in static images. The next step of the validation process is to assess the reliability of the scoring system in a patient-based exercise. This study represents a fundamental step in the OMERACT process of validating US as an outcome measure instrument, and above proposed scoring system will hopefully provide a useful tool for clinical practice and research.

Disclosure of Interests

None declared

POS0276 TRADITION VS INNOVATION! CONVENTIONAL RADIOGRAPHY AND ULTRASOUND IN THE DIAGNOSIS OF CPPD: INSTRUCTIONS FOR USE

Background

Conventional radiography (CR) is widely used as the first-line investigation for calcium pyrophosphate deposition (CPPD) disease, given its widespread use and the low cost. Next to it a series of advanced imaging techniques have been evaluated for accuracy and reliability. Among them, ultrasound (US) has been thoroughly tested and demonstrated to be accurate and reliable for CPPD diagnosis. However, even if there are data on the diagnostic accuracy of US and CR alone, it is not clear if performing both diagnostic tests and in which sequential order provides an added value for the diagnosis of CPPD.

Objectives

The aim of this study was to assess which diagnostic test performs better for the diagnosis of CPPD and if a combination of the two exams provides an additional value.

Methods

This is an ancillary study of the criterion validity of US in CPPD study1. Consecutive patients with knee osteoarthritis requiring total joint replacement were enrolled in 8 centres. Participants underwent US and CR of the affected knee prior to surgery. US was performed by experienced sonographers following the same scanning protocol described in the main study, while CR were performed in weight bearing AP and lateral views and were read by 2 experienced radiologists that reached a consensus on the presence/absence of CPPD. The evaluation of CPPD at the level of menisci and hyaline cartilage (HC) was based on the OMERACT definitions for US and on the new definitions developed by the ACR/EULAR CPPD classification criteria working group for CR [paper under submission]. Patients were classified as having CPPD considering histological examination as reference standard. Diagnostic indexes were calculated for US and CR alone and combined. Poisson models with robust estimation were used to estimate the best sequence of these diagnostic methods for a more accurate diagnosis of CPPD.

Results

51 pts were enrolled (63% F, mean age 74y ± 8). Diagnostic indexes of US and CR alone and combined are indicated in Table 1. Compared to histology, US demonstrated to be a sensitive tool for identification of CPPD at the knee, with a good sensitivity in all sites and in the overall evaluation. Instead, CR was less sensitive, but it was a highly specific exam for CPPD identification. Combining US and CR led to a higher sensitivity compared with CR alone, but a lower specificity compared to both CR and US alone, and it offered no additional increase in diagnostic accuracy. The Figure 1 shows the results of the appropriate sequence of use of US and CR in patients with suspected CPPD: in case of a positive CR at any of the 3 sites (menisci and HC) no additional exam is necessary, and the same in case of a positive US in at least two sites; however in case of a negative CR, US could help in a statistically significant way to identify CPPD patients, and further in case of a positive US in a single site CR can offer additional information.

Table 1.

diagnostic indexes of US, CR and US + CR in the identification of CPPD. MM: medial meniscus, LM: lateral meniscus, HC: hyaline cartilage, SN: sensitivity, SP: specificity, PPV: positive predictive value, NPV: negative predictive value, ACC: accuracy.

USSNSPPPVNPVACCMM0.880.810.820.880.84LM0.880.730.760.860.80HC0.780.860.820.830.82Overall0.920.640.730.890.78CRMM0.32110.610.67LM0.400.960.910.630.69HC0.480.930.850.680.73Overall0.540.920.880.660.73US + CRMM0.880.810.820.880.84LM0.920.690.740.900.80HC0.870.820.800.890.84Overall0.920.560.670.880.75Figure 1.

evaluation of sequence of US and CR

Conclusion

US confirmed a high diagnostic accuracy in identifying patients affected by CPPD at knee level, while CR demonstrated a high specificity but a low sensitivity. Performing both diagnostic tests could make sense in case of a negative CR or in case of an inconclusive US (only one positive site). To our knowledge, this is the first study that investigates the role of the combination of the two exams in CPPD. Further studies in a large number of patients and in different joints would be helpful to address this point.

References

[1]Filippou G. et al, Ann Rheum Dis, 2020

Disclosure of Interests

None declared

OP0291 SCORING STRUCTURAL DAMAGE IN RHEUMATOID ARTHRITIS BY ULTRASOUND: RESULTS FROM A DELPHI PROCESS AND WEB-RELIABILITY EXERCISE BY THE OMERACT US WORKING GROUP

Background

Structural damage in rheumatoid arthritis (RA) includes bone erosion, cartilage change, and joint malalignment; historically evaluated with conventional radiography. Ultrasound (US) has been shown to be a valid tool for evaluating both cartilage change and bone erosion.

Objectives

To obtain agreement on definitions and develop semiquantitative scoring systems for assessing structural damage by US and to validate these in a web-based reliability exercise.

Methods

A Delphi survey of statements was prepared by an OMERACT US Working Group task force (USWG) based on a previously published systematic literature review (1) and circulated between group members, including definitions on normal US appearance of joint components, definitions of elementary lesions and scoring systems for bone erosions and joint malalignment. Definitions and a US scoring system for scoring cartilage change were recently developed and validated by the USWG (2) After agreement was achieved (≥75% of grades 4-5 on 1-5 Likert scale) on the statements, still images of metacarpophalangeal and proximal interphalangeal joints 2-5 in healthy controls and in RA patients with varying degrees of pathology were acquired by the USWG members. A dataset of 100 anonymized images, representing various grades of the 3 components of structural damage was created and utilized in 2 rounds of a web-based exercise. Intra- and inter-reader reliability of the scoring systems was assessed by kappa statistics.

Results

19 USWG members needed 4 Delphi rounds to reach agreement on a total of 9 statements. 4/12 statements were approved in the first, 2/6 in the second, 1/5 in the third and 2/2 in the fourth round. Final scoring systems and representative images are shown in Table 1 & Figure 1. 22 members participated in the web-based reliability exercise. The intra-reader reliability was almost perfect for bone erosion (kappa: 0.87) and cartilage change (kappa: 0.83) and substantial for malalignment (kappa of 0.72). The inter-reader reliability was almost perfect for bone erosion (kappa: 0.85), and substantial for cartilage change (kappa: 0.79) and malalignment (0.62).

Table 1.

Final definitions of scoring systems of elementary lesions of structural damage in rheumatoid arthritis

AgreementBone erosionA 4-grade semiquantitative scoring system can be used to score erosions as follows: grade 0. intact cortical bone; grade 1. single small erosion (diameter: ≤2mm); grade 2. single large erosion (diameter: >2mm) or 2 small erosions; grade 3. 2 large erosions or ≥3 erosions, regardless of size. Both longitudinal and transverse scans should be considered, and the largest measure chosen for each erosion.100%Cartilage changeA 3-grade semiquantitative scoring system can be used to grade hyaline cartilage change as follows: grade 0. normal cartilage; grade 1. minimal change: focal thinning or incomplete loss of cartilage; grade 2. severe change: diffuse thinning or complete loss of cartilage.80% (2)MalalignmentA 3-grade semiquantitative scoring system can be used to grade malalignment as follows: 0. normal alignment; 1. subluxation or partial dislocation, where the two bone endings are malaligned so that one bone ending is dislocated from its normal position, but still within the articulation; 2. luxation or total dislocation, where the luxated bone ending moves beyond the articulation and the opposing bone ending. Bone position may be compared with a contralateral or similar intact joint if available.94%Figure 1.

Representative images of the scoring systems for bone erosion (A), cartilage change (B) and malalignment (C)

Conclusion

This first attempt to create a composite US instrument based on scoring systems encompassing all aspects of structural damage, demonstrates that US is a reliable tool for evaluating and scoring bone erosion, cartilage change and malalignment in the finger joints of RA patients.

References

[1]Gessl I, et al. Semin Arthritis Rheum. 2021 Jun;51(3):627-39.

[2]Mandl P, et al. Rheumatology (Oxford). 2019 Oct 1;58(10):1802-11.

Disclosure of Interests

Peter Mandl Speakers bureau: AbbVie, Janssen, Lilly, Novartis, Consultant of: AbbVie, Janssen, Lilly, Novartis, Grant/research support from: AbbVie, BMS, Novartis, Janssen, Lilly, MSD, UCB, Irina Gessl: None declared, Georgios Filippou: None declared, Silvia Sirotti: None declared, Lene Terslev Speakers bureau: Novartis, Pfizer, UCB, Janssen, GE, Carlos Pineda: None declared, Helen Keen Speakers bureau: Roche, AbbVie, Janssen, Consultant of: Sanofi, Marina Backhaus: None declared, David Andrew Bong: None declared, Edoardo Cipolletta: None declared, PAZ COLLADO: None declared, Christian Dejaco Speakers bureau: Roche, AbbVie, Sanofi, Lilly, Pfizer, Novartis, Janssen, Galapagos, Consultant of: Roche, AbbVie, Sanofi, Lilly, Pfizer, Novartis, Janssen, Galapagos, Andrea Delle Sedie Speakers bureau: Abbvie, Amgen, Lilly, MSD, Novartis, UCB, Paid instructor for: Abbvie, Amgen, Lilly, MSD, Novartis, UCB, Consultant of: Abbvie, Amgen, Lilly, MSD, Novartis, UCB, Christina Duftner: None declared, Hilde Berner Hammer: None declared, Annamaria Iagnocco: None declared, Zunaid Karim: None declared, Ingrid Möller Speakers bureau: Bristol-Myers Squibb, Ibsa, Pfizer, Galapagos, Esperanza Naredo Speakers bureau: Abbvie, Pfizer, Lilly, Novartis, Janssen, Celgene GmbH, Paid instructor for: Novartis, Consultant of: Novartis, Lilly, Grant/research support from: Lilly, Pfizer, Wolfgang A. Schmidt: None declared, Marcin Szkudlarek: None declared, Giorgio Tamborrini: None declared, Priscilla C Wong: None declared, Emilio Filippucci Speakers bureau: AbbVie, Amgen, Bristol -Myers Squibb, Janssen-Cilag, Lilly, Novartis, Pfizer, Roche, Union Chimique Belge Pharma, Peter Balint Speakers bureau: Abbvie, Janssen, Lilly, Novartis, Maria-Antonietta D’Agostino: None declared

Inflammasome genes polymorphisms and susceptibility to gout. Is there a link?

Background

The inflammatory response in gout disease is induced by the activation of NLR family pyrin domain-containing 3 (NLPR3) signaling pathway mediated by IL-1β release.

Objective

The objective of the study was to determine the association between single nucleotide polymorphisms (SNPs) within NLRP3 inflammasome genes and gout susceptibility.

Methods

Mexican patients with gout from the National Rehabilitation Institute and General Hospital of Mexico were enrolled. A healthy control group was also included. We analyzed the frequency and allelic distribution of eight SNPs from seven different genes within the NLRP3 inflammasome signaling pathway: TLR4 rs2149356, CD14 rs2569190, NLRP3 rs3806268, NLRP3 rs10754558, CARD8 rs2043211, IL-1β rs1143623, P2RX7 rs3751142, and PPARGC1B rs45520937 SNPs.

Results

We found that the SNP rs45520937 of PPARGC1B was associated with the risk of developing gout when it was analyzed using the dominant model (Odds ratio [OR] = 2.30; 95% confidence interval [CI]: 1.09-4.86; p = 0.030), and it is proposed that the adaptor molecule CD14 rs2569190 polymorphism could be associated with a lower risk of gout under an additive model (OR= 0.41;95% CI: 0.16-1.05; p = 0.064). No significant associations were identified for the remaining SNPs.

Conclusion

Our findings suggest that the PPARGC1B rs45520937 SNP is associated with gout susceptibility.

Dynamics of ranking

Virtually anything can be and is ranked; people, institutions, countries, words, genes. Rankings reduce complex systems to ordered lists, reflecting the ability of their elements to perform relevant functions, and are being used from socioeconomic policy to knowledge extraction. A century of research has found regularities when temporal rank data is aggregated. Far less is known, however, about how rankings change in time. Here we explore the dynamics of 30 rankings in natural, social, economic, and infrastructural systems, comprising millions of elements and timescales from minutes to centuries. We find that the flux of new elements determines the stability of a ranking: for high flux only the top of the list is stable, otherwise top and bottom are equally stable. We show that two basic mechanisms — displacement and replacement of elements — capture empirical ranking dynamics. The model uncovers two regimes of behavior; fast and large rank changes, or slow diffusion. Our results indicate that the balance between robustness and adaptability in ranked systems might be governed by simple random processes irrespective of system details.

Ranking lists are relevant to various areas of nature and society, however their evolution with the elements changing rank in time remained unexplored. The authors uncover a mechanism of ranking dynamics induced by the flux governing the arrival of new elements in the list, for improved predictability of ranking models.

mtDNA haplogroup A enhances the effect of obesity on the risk of knee OA in a Mexican population

To evaluate the influence of mitochondrial DNA haplogroups on the risk of knee OA in terms of their interaction with obesity, in a population from Mexico. Samples were obtained from (n = 353) knee OA patients (KL grade ≥ I) and (n = 364) healthy controls (KL grade = 0) from Mexico city and Torreon (Mexico). Both Caucasian and Amerindian mtDNA haplogroups were assigned by single base extension assay. A set of clinical and demographic variables, including obesity status, were considered to perform appropriate statistical approaches, including chi-square contingency tables, regression models and interaction analyses. To ensure the robustness of the predictive model, a statistical cross-validation strategy of B = 1000 iterations was used. All the analyses were performed using boot, GmAMisc and epiR package from R software v4.0.2 and SPSS software v24. The frequency distribution of the mtDNA haplogroups between OA patients and healthy controls for obese and non-obese groups showed the haplogroup A as significantly over-represented in knee OA patients within the obese group (OR 2.23; 95% CI 1.22–4.05; p-value = 0.008). The subsequent logistic regression analysis, including as covariate the interaction between obesity and mtDNA haplogroup A, supported the significant association of this interaction (OR 2.57; 95% CI 1.24–5.32; p-value = 0.011). The statistical cross-validation strategy confirmed the robustness of the regression model. The data presented here indicate a link between obesity in knee OA patients and mtDNA haplogroup A.

ACE and ACE2 Gene Variants Are Associated With Severe Outcomes of COVID-19 in Men

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic, affecting more than 219 countries and causing the death of more than 5 million people worldwide. The genetic background represents a factor that predisposes the way the host responds to SARS-CoV-2 infection. In this sense, genetic variants of ACE and ACE2 could explain the observed interindividual variability to COVID-19 outcomes. In order to improve the understanding of how genetic variants of ACE and ACE2 are involved in the severity of COVID-19, we included a total of 481 individuals who showed clinical manifestations of COVID-19 and were diagnosed by reverse transcription PCR (RT-PCR). Genomic DNA was extracted from peripheral blood and saliva samples. ACE insertion/deletion polymorphism was evaluated by the high-resolution melting method; ACE single-nucleotide polymorphism (SNP) (rs4344) and ACE2 SNPs (rs2285666 and rs2074192) were genotyped using TaqMan probes. We assessed the association of ACE and ACE2 polymorphisms with disease severity using logistic regression analysis adjusted by age, sex, hypertension, type 2 diabetes, and obesity. The severity of the illness in our study population was divided as 31% mild, 26% severe, and 43% critical illness; additionally, 18% of individuals died, of whom 54% were male. Our results showed in the codominant model a contribution of ACE2 gene rs2285666 T/T genotype to critical outcome [odds ratio (OR) = 1.83; 95%CI = 1.01–3.29; p = 0.04] and to require oxygen supplementation (OR = 1.76; 95%CI = 1.01–3.04; p = 0.04), in addition to a strong association of the T allele of this variant to develop critical illness in male individuals (OR = 1.81; 95%CI = 1.10–2.98; p = 0.02). We suggest that the T allele of rs2285666 represents a risk factor for severe and critical outcomes of COVID-19, especially for men, regardless of age, hypertension, obesity, and type 2 diabetes.

A poly (saccharide-ester-urethane) scaffold for mammalian cell growth

Chitosan and poly(3-hydroxybutyrate) are non-toxic, biodegradable, and biocompatible polymers extensively used in regenerative medicine. However, it is unknown whether the chemical combination of these polymers can produce a biomaterial that induces an appropriate cellular response in vitro in mammalian cells. This study aimed to test the ability of a novel salt-leached polyurethane scaffold of chitosan grafted with poly(3-hydroxybutyrate) to support the growth of three mammalian cell lines of different origin: a) HEK-293 cells, b) i28 mouse myoblasts, and c) human dermal fibroblasts. The viability of the cells was assessed by either evaluation of their capacity to maintain the expression of the green fluorescent protein by adenoviral transduction or by esterase activity and plasma membrane integrity. The results indicated that the three cell lines attached well to the scaffold; however, when i28 cells were induced to differentiate, they did not produce morphologically distinct myofibers, and cell growth ceased. In conclusion, the findings reveal that, altogether, these observations suggest that this foam scaffold supports cell growth and proliferation but may not apply to all cell types. Hence, one crucial question yet to be resolved is a poly (saccharide-ester-urethane) derivative with a nano-topography that elicits a similar cellular response for different biological environments.

Development of a new ultrasound scoring system to evaluate glandular inflammation in Sjögren's syndrome: an OMERACT reliability exercise

OBJECTIVE

The aim of this exercise from the OMERACT ultrasound subgroup on Sjögren's syndrome (pSS) was to develop and assess the reliability of a consensus-based semiquantitative colour Doppler (CD) ultrasound scoring system for pathologic salivary gland vascularization in patients with pSS.

METHODS

Using the Delphi method a CD semiquantitative scoring system for vascularization of bilateral parotid and submandibular glands was developed and tested in static images and on patients (9 pSS patients and 9 sonographers). Intra-reader and inter-reader reliability of grading the salivary glands were computed by weighted Cohen and Light's kappa (κ) analysis, respectively.

RESULTS

The consensus-based semiquantitative score was: Grade 0, no visible vascular signals; Grade 1, focal, dispersed vascular signals; Grade 2, diffuse vascular signals detected in < 50% of the gland; Grade 3, diffuse vascular signals in > 50% of the gland. In static images, the intra- and inter-reader reliability showed excellent κ values (95% confidence interval) = 0.90 (0.87-0.93) and 0.80 (0.74-0.84), respectively) for all four salivary glands together. In patients, the intra- and inter-reader reliability for all four salivary glands together was κ  = 0.84 (0.73-0.92) and 0.70 (0.64-0.76), respectively.

CONCLUSION

The consensus-based CD ultrasound scoring for the evaluation of salivary gland vascularization in pSS showed a good inter-reader reliability and excellent intra-reader reliability in static images and in patients. The clinical application of the developed scoring system should be tested in clinical settings.

Complex Regional Pain Syndrome Evolving to Full-Blown Fibromyalgia: A Proposal of Common Mechanisms

BACKGROUND

Spread of complex regional pain syndrome (CRPS) outside the affected limb is a well-recognized phenomenon; nevertheless, the actual evolution from CRPS to fibromyalgia is poorly documented. Similar mechanisms have been recently put forward to explain the development of CRPS and fibromyalgia including dorsal root ganglia (DRG) hyperexcitability and small fiber neuropathy.

OBJECTIVES

The aims of this study were to describe 3 cases with typical CRPS evolving to full-blown fibromyalgia and to discuss the potential pathogenetic mechanisms linking these debilitating illnesses.

METHODS

This was a review of medical records and PubMed search on the relationship between CRPS-fibromyalgia with DRG and small nerve fiber neuropathy.

RESULTS

Our 3 cases displayed over time orderly evolution from CRPS to fibromyalgia. Dorsal root ganglion hyperexcitability and small fiber neuropathy have been recently demonstrated in CRPS and in fibromyalgia. Dorsal root ganglia contain the small nerve fiber cell bodies surrounded by glial cells. After trauma, DRG perineuronal glial cells produce diverse proinflammatory mediators. Macrophages, lymphocytes, and satellite glial cells may drive the immune response to more rostrally and caudally located DRG and other spinal cord sites. Dorsal root ganglion metabolic changes may lead to small nerve fiber degeneration. This mechanism may explain the development of widespread pain and autonomic dysfunction.

CONCLUSIONS

Clinicians should be aware that CRPS can evolve to full-blown fibromyalgia. Spreading of neuroinflammation through DRG glial cell activation could theoretically explain the transformation from regional to generalized complex pain syndrome.

Very low prevalence of ultrasound-detected tenosynovial abnormalities in healthy subjects throughout the age range: OMERACT ultrasound minimal disease study

Objectives

This study aimed to determine the prevalence of ultrasound-detected tendon abnormalities in healthy subjects (HS) across the age range.

Methods

Adult HS (age 18–80 years) were recruited in 23 international Outcome Measures in Rheumatology ultrasound centres and were clinically assessed to exclude inflammatory diseases or overt osteoarthritis before undergoing a bilateral ultrasound examination of digit flexors (DFs) 1–5 and extensor carpi ulnaris (ECU) tendons to detect the presence of tenosynovial hypertrophy (TSH), tenosynovial power Doppler (TPD) and tenosynovial effusion (TEF), usually considered ultrasound signs of inflammatory diseases. A comparison cohort of patients with rheumatoid arthritis (RA) was taken from the Birmingham Early Arthritis early arthritis inception cohort.

Results

939 HS and 144 patients with RA were included. The majority of HS (85%) had grade 0 for TSH, TPD and TEF in all DF and ECU tendons examined. There was a statistically significant difference in the proportion of TSH and TPD involvement between HS and subjects with RA (HS vs RA p<0.001). In HS, there was no difference in the presence of ultrasound abnormalities between age groups.

Conclusions

Ultrasound-detected TSH and TPD abnormalities are rare in HS and can be regarded as markers of active inflammatory disease, especially in newly presenting RA.

Accuracy of synovial fluid analysis compared to histology for the identification of calcium pyrophosphate crystals: an ancillary study of the OMERACT US Working Group - CPPD subgroup

The aim of this study was to evaluate the accuracy of synovial fluid analysis in the identification of calcium pyrophosphate dihydrate crystals compared to microscopic analysis of joint tissues as the reference standard. This is an ancillary study of an international, multicentre cross-sectional study performed by the calcium pyrophosphate deposition disease (CPPD) subgroup of the OMERACT Ultrasound working group. Consecutive patients with knee osteoarthritis (OA) waiting for total knee replacement surgery were enrolled in the study from 2 participating centres in Mexico and Romania. During the surgical procedures, synovial fluid, menisci and hyaline cartilage were collected and analysed within 48 hours from surgery under transmitted light microscopy and compensated polarised light microscopy for the presence/absence of calcium pyrophosphate crystals. All slides were analysed by expert examiners on site, blinded to other findings. A dichotomic score (absence/ presence) was used for scoring both synovial fluid and tissues. Microscopic analysis of knee tissues was considered the gold standard. Sensitivity, specificity, accuracy, positive and negative predictive values of synovial fluid analysis in the identification of calcium pyrophosphate crystals were calculated. 15 patients (53% female, mean age 68 yo ± 8.4) with OA of grade 3 or 4 according to Kellgren-Lawrence scoring were enrolled. 12 patients (80%) were positive for calcium pyrophosphate crystals at the synovial fluid analysis and 14 (93%) at the tissue microscopic analysis. The overall diagnostic accuracy of synovial fluid analysis compared with histology for CPPD was 87%, with a sensitivity of 86% and a specificity of 100%, the positive predictive value was 100% and the negative predictive value was 33%. In conclusion synovial fluid analysis proved to be an accurate test for the identification of calcium pyrophosphate dihydrate crystals in patients with advanced OA.

Are antiphospholipid antibodies just a common epiphenomenon or are they causative of immune-mediated coagulopathy in COVID-19?

The coronavirus disease 2019 (COVID-19) is the largest public health emergency in recent times. A significant number of patients develop a severe form of COVID-19 characterized by coagulopathy, organ failure, and elevated mortality. In addition, an unusually high frequency of antiphospholipid antibodies (aPLs) has been found in patients with COVID-19. These clinical and serological manifestations closely resemble those seen in the antiphospholipid syndrome (APS), especially in its catastrophic form, suggesting a role of aPLs in immune-associated coagulopathy. However, government bodies such as the American Society of Hematology have spoken out against the systematic search for aPLs in patients with COVID-19. In an attempt to bridge the gap on this hot topic, we conducted a comprehensive review of currently available cohort studies and case series systematically evaluating aPLs in COVID-19 patients. In this Perspective, we seek to identify both the frequency and the type of aPLs found in patients with COVID-19, as well as the potential association of these aPLs with vascular thrombosis and other distinctive characteristics of COVID-19. Furthermore, we investigated whether there is evidence that allows us to define the occurrence of aPLs in COVID-19 as an epiphenomenon, as has been observed in other systemic viral infections, or as antibodies against self-antigens bearing hallmarks that suggest a pathogenic role in immune-mediated thrombosis. Defining whether aPLs represent an epiphenomenon or they are actually involved in hemostatic abnormalities of COVID-19 is crucial both for uncovering novel mechanisms of immune-mediated thrombosis and for identifying potential prognostic biomarkers in this devastating disease.

Refractory fibromyalgia

In the medical literature, there are only a few references on refractory fibromyalgia and there is no consensus definition available on this concept. Some definitions of refractory fibromyalgia have been proposed based on the lack of response to a number of medications, and perhaps the most appropriate term is treatment-refractory fibromyalgia. To achieve the definition of treatment-refractory fibromyalgia, it is necessary to consider several previous steps, such as making sure the diagnosis has been made properly and a differential diagnosis with entities that can mimic fibromyalgia symptoms (including complete physical examination and laboratory test) has been made. The possibility that another factor that alters the response to treatment should be investigated, and in particular review all prescribed medication and search for some non-medical reasons that could mask the response to treatment (e.g., legal compensation). The definition of refractory fibromyalgia is complex and probably should include a lack of response to a specified number of drugs or to combination therapy with at least two non-pharmacological measures. In this article, it is not our purpose to present a formal definition, but to raise the possible bases for this purpose. We believe that it is a subject that must be discussed extensively before reaching a consensus definition. Key Points • There is no appropriate definition to classify fibromyalgia patients who do not respond to the usual pharmacological and non-pharmacological measures according to the national or international guidelines. • A consensus definition is required to classify these patients, which could help standardize future management strategies. In this article, we propose the bases on which refractory fibromyalgia could be defined.

Quantifying Potential Cost-Savings Through an Alternative Imaging-Based Diagnostic Process in Presumptive Seronegative Rheumatoid Arthritis

Background

Seronegative rheumatoid arthritis (SRA) is a condition that is not well understood and difficult to confirm by a conventional diagnostic process. We aimed to quantify the potential cost-savings of an alternative diagnostic process (ADP) imaging-based, for patients with presumptive SRA from everyday clinical practice.

Methods

We performed a retrospective analysis for patients with presumptive SRA who tested negative for both rheumatoid factor and anti-cyclic citrullinated peptide antibodies, through an ADP imaging-based, that is a standard clinical practice in our center. After we confirmed the diagnosis of SRA or reclassified patients in terms of another proper diagnosis, we estimate direct costs in two scenarios: a conventional and ADP. We compared the cost of RA treatment during the first year against the cost of the most misdiagnosed treatment (osteoarthritis) found after applying the ADP to determine potential cost-savings.

Results

We included 440 patients with a presumptive diagnosis of SRA. According to the imaging-based ADP, SRA was confirmed in 106/440 (24.1%), unspecified RA in 9/440 (2.0%), and osteoarthritis in 325/440 (73.9%) of those patients. Although the costs of conventional diagnosis per patient is lower than those of ADP ($59,20 USD vs $269,57 USD), we found a potential drug cost-savings of $1,570,775.20 US Dollars after 1 year of correct treatment.

Conclusion

An alternative diagnosis process, including X-rays, US and MRI imaging, and clinical and blood-test assessment, not only increased diagnostic certainty in patients referred for evaluation of presumptive SRA but also suggested a potential cost-savings in pharmacological treatments avoided in misdiagnosed patients.

AB0531 THERAPIES FOR PERIPHERAL JOINT INVOLVEMENT IN PSORIATIC ARTHRITIS: A SYSTEMATIC LITERATURE REVIEW

Background:

Much new information has been reported since the last evidence-based GRAPPA recommendations for the treatment of psoriasis and psoriatic arthritis (PsA).

Objectives:

We aimed to compile the evidence for the efficacy and safety of established and newly developed drugs targeting the peripheral arthritis domain in PsA so as to provide information for the revised GRAPPA treatment recommendations.

Methods:

A working group consisting of clinicians and patient research partners (PRPs) was convened. We performed an updated systematic literature review (SLR) of randomized controlled trials (RCTs) for the treatment of PsA, including peripheral arthritis, from the date of the last GRAPPA SLR, from February 19, 2013 to August 28, 2020. The working group reviewed the evidence supporting the efficacy on peripheral arthritis for each class of drug, according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, for three patients groups: 1) naïve to treatment; 2) refractory to conventional (-c)DMARDs; and 3) with prior biological (-b)DMARD experience. We also evaluated the evidence for non-pharmacological treatments. A set of important outcomes for the peripheral arthritis domain was assessed for each class of medication. The certainty of evidence supporting each class of drugs for each patient group was evaluated. Recommendations were derived through consensus meetings.

Results:

87 articles from 52 RCTs were included. For patients with mild disease who are naïve to treatment, the working group strongly recommends csDMARDs (methotrexate, sulfasalazine, leflunomide) and PDE4i, and weakly recommends them for severe disease, where TNFi are preferred over csDMARDs. Other bDMARDs (IL-17i, IL-12/23i, IL-23i) and JAKi are strongly recommended to treat peripheral arthritis for treatment naïve patients. For patients with inadequate response to csDMARDs, we strongly recommend TNFi, IL-17i, IL-12/23i, IL-23i and JAKi. For those who had prior experience with bDMARDs, we strongly recommend a second TNFi, IL-17i, IL-23i and JAKi. Certainty of evidence (GRADE) and recommendations for peripheral arthritis domain of PsA for different population groups are shown in Table 1. While the evidence supporting non-pharmacological treatments was low, we derived the recommendations from clinician/PRP expert opinion, included advocating an increase in physical activity, smoking cessation and a healthy diet to control weight gain.

Conclusion:

Evidence supporting drug treatment for the peripheral arthritis domain of PsA was compiled, providing required information for the revised GRAPPA treatment recommendations. Further work seeking agreement from a broader group of stakeholders is in progress.

Table 1.

Certainty of evidence (GRADE) and Recommendation for peripheral arthritis of PsA

Treatment naivecsDMARD inadequate responsebDMARD inadequate responseDrug classevidence (GRADE)Recom-mendationevidence (GRADE)Recom-mendationevidence (GRADE)Recom-mendationPDE-4iMod to highStrong for(mild/ mod disease)Conditional for(severe disease)Mod to HighStrong forbDMARD exp: ModbDMARD IR: Mod (NS)Conditional for (bDMARD exp)Conditional against (bDMARD IR)TNFiHighStrong forHighStrong forModStrong fora 2ndTNFiTNFiVs. MTXHighStrong for TNFi as 1st line for severe disease----IL-17iHighStrong forHighStrong forMod to highStrong forIL-12/23iMod to highStrong forMod to HighStrong forLowConditional forIL-23iHighStrong forHighStrong forModStrong forJAKiMod*Strong forHighStrong forMod to HighStrong forCTLA4iVery LowConditional for†LowConditional for†Mod (NS)Conditional for†Dual TNFi/ IL17iModerateNA¥ModNA¥NANA¥IL-6iVery LowConditional againstVery low to lowConditional againstNAConditional against

NS: not statistically significant; *included data from abstract; ¥ not making recommendation due to not approved and not available in market; †reserve for no alternatives. Mod: Moderate; exp: experienced; IR: inadequate response.

Acknowledgements:

We are grateful to the contribution of our patient research partner, Rodrigo Firmino.

Disclosure of Interests:

None declared.

AB0629 ACCURACY OF SYNOVIAL FLUID ANALYSIS FOR THE IDENTIFICATION OF CALCIUM PYROPHOSPHATE CRYSTALS: AN ANCILLARY STUDY OF OMERACT CRITERION VALIDITY STUDY FOR ULTRASOUND IN CPPD

Background:

Synovial fluid analysis (SFA) via compensated polarized light microscopy is still considered the gold standard for the identification and diagnosis of Calcium Pyrophosphate Deposition disease (CPPD)-related arthropathies[1], but very few studies have been published about its diagnostic accuracy.

Objectives:

The aim of this study was to evaluate the accuracy of SFA in the identification of calcium pyrophosphate dihydrate (CPP) crystals compared to microscopic analysis of joint tissues as the reference standard.

Methods:

This is an ancillary study of an international, multicentre cross-sectional study performed by the CPPD subgroup of the OMERACT Ultrasound working group[2]. Consecutive patients with knee osteoarthritis (OA) waiting for total knee replacement surgery were enrolled in the study from 2 participating centres, Mexico and Romania. During surgical procedures synovial fluid (SF), menisci and hyaline cartilage were collected and analysed within 48 hours after surgery under transmitted light microscopy and compensated polarised light microscopy for the presence/absence of CPP crystals. All slides were analysed by expert examiners on site, blinded to other findings. A dichotomic score (absence/presence) was used for scoring both SF and tissues. Microscopic analysis of knee tissues was considered the gold standard. Sensitivity, specificity, accuracy, positive and negative predictive values (PPV and NPV) of SFA in the identification of CPP crystals were calculated.

Results:

15 patients (53% female, mean age 68yo ± 8.4) with OA of grade 3 or 4 according to Kellgren-Lawrence scoring were enrolled. 12 patients (80%) were positive for CPP crystals at SFA and 14 (93%) at tissues microscopic analysis. Among 12 SFA positive patients, all were positive for CPP crystals in either medial or lateral meniscus, and 11 were positive in both; 10 patients were positive at the hyaline cartilage, and all 10 were also positive for at least one meniscus. Regarding the 3 SFA negative patients, only one had no crystals in the examined tissues, while the other 2 patients had CPP crystals in both menisci and hyaline cartilage. The overall diagnostic accuracy of SFA compared to histology analysis for CPPD was 87%, with a sensitivity of 86% and a specificity of 100%, the PPV was 100% and the NPV was 33% (Table 1).

Table 1.

sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy of synovial fluid analysis compared to the reference standard. CI: Confidential Interval. SF: synovial fluid, in parentheses: numerators and denominators for all percentages provided.

SensitivitySpecificityPPVNPVAccuracySF analysis86% (12/14)100% (1/1)100% (12/12)33% (1/3)87% (13/15)(0.65-0.99) CI 95%(0.0-0.25) CI 95%(0.65-0.99) CI 95%(0.0-0.25) CI 95%

Conclusion:

SFA demonstrated to be an accurate test for the identification of CPP crystals in patients with advanced OA. However, is not always feasible and carries some risks for the patient. Considering the availability of validated imaging techniques for the detection of CPPD, such as US, SFA could be used in those patients where imaging and clinical data are not definitely confirmatory of the disease.

References:

[1]W. Zhang et al., ‘European League Against Rheumatism recommendations for calcium pyrophosphate deposition. Part I: terminology and diagnosis’, Ann Rheum Dis, vol. 70, no. 4, pp. 563–570, Apr. 2011, doi: 10.1136/ard.2010.139105.

[2]G. Filippou et al., ‘Criterion validity of ultrasound in the identification of calcium pyrophosphate crystal deposits at the knee: an OMERACT ultrasound study’, Ann Rheum Dis, p. annrheumdis-2020-217998, Sep. 2020, doi: 10.1136/annrheumdis-2020-217998.

Disclosure of Interests:

None declared.

POS1132 DIAGNOSTIC ACCURACY OF CONVENTIONAL RADIOGRAPHY OF THE KNEE FOR CALCIUM PYROPHOSPHATE DEPOSITION DISEASE: AN ANCILLARY STUDY OF THE OMERACT ULTRASOUND – CPPD GROUP

Background:

Conventional Radiography (CR) has been widely used in the assessment of knee chondrocalcinosis (CC) and is still considered one of the most important diagnostic methods for the diagnosis. However, there are very few studies that examine the diagnostic accuracy of CR compared to histology of the knee tissues.

Objectives:

To assess the diagnostic accuracy of CR of the knee in Calcium Pyrophosphate Deposition Disease (CPPD) by using the recently created definitions for CPPD in CR of the ACR/EULAR taskforce for the new classification criteria for CPPD.

Methods:

This is an ancillary study of the Criterion Validity of Ultrasound in CPPD study [1]. Consecutive patients with osteoarthritis (OA) awaiting total knee replacement were enrolled in 4 centres from Romania, Italy, USA and Mexico. All patients underwent CR of the knees taken maximum 6 months before surgery, in posterior-anterior weight baring and lateral projections. DICOM files of the radiographs were anonymised and read independently by two musculoskeletal radiologists with experience in microcrystalline arthropathies. For each patient, a dichotomic score was used (absence/presence of CC) at the level of the menisci and tibiofemoral hyaline cartilage by each reader. The definitions of the ACR/EULAR taskforce for identification of CPPD in CR were used in this study [paper in preparation]. According to these definitions CPPD in CR appears as “linear or punctate opacities in the region of fibro- or hyaline articular cartilage/synovial membrane or joint capsule/within tendons or entheses that are distinct from denser, nummular radio-opaque deposits due to basic calcium phosphate deposition”. In case of disagreement a consensus decision was taken by both radiologists after discussion of the case. Menisci and the hyaline cartilage were analysed using compensated polarized light microscopy as described previously [1], patients were considered positive for CPPD if at least one of their tissue specimens revealed the presence of calcium pyrophosphate crystals. All examiners were blind to each other’s findings.

Results:

We enrolled 33 patients with OA (61% female, mean age 69yo). The accuracy values of CR in the various sites of the knee are indicated in Table 1. CR demonstrated to be a specific exam for identification of CPPD at the knee, but sensitivity remains low in all sites and in the overall evaluation. Identification of CPPD appears challenging and this could be due to the advanced grade of OA in our cohort of patients. Advanced degeneration, dislocation of the menisci and thinning of the hyaline cartilage in these patients is frequent and the eventual presence of calcific deposits in one of these structures could overlap with other anatomical structures making the exact localisation difficult. According to the results of the predictive values, the presence of typical deposition on CR allows a definite confirmation of the diagnosis, but a negative radiography does not exclude CPPD as testified by the low negative predictive value.

Table 1.

Sensitivity, specificity, PPV, NPV, accuracy and AUC of CR for identification of CPPD by using the new ACR/EULAR taskforce definitions.

Medial meniscusLateral meniscusHyaline cartilageOverallSensitivity22%33%31%42%Specificity100%100%85%90%Positive predictive value100%100%67%80%Negative predictive value56%60%55%61%Accuracy61%68%58%66%AUC0.60.70.60.7

Conclusion:

CR has been extensively used for the diagnosis of OA and CPPD and has been tested previously for diagnostic accuracy. The results of our study confirm that the presence of typical CPPD calcifications, as defined by the ACR/EULAR task force, are highly specific but have low sensitivity for disease identification when using CR. Absence of CPPD on CR does not exclude the diagnosis.

References:

[1]Filippou G, et al. Criterion validity of ultrasound in the identification of calcium pyrophosphate crystal deposits at the knee: an OMERACT ultrasound study. Ann Rheum Dis 2020. doi:10.1136/annrheumdis-2020-217998

Disclosure of Interests:

None declared.

POS1141 ASSESSING RELEVANT JOINTS FOR MONITORING CPPD DISEASE: A SYSTEMATIC LITERATURE REVIEW OF IMAGING TECHNIQUES BY THE OMERACT ULTRASOUND – CPPD SUBGROUP

Background:

Imaging has been extensively used for the Calcium Pyrophosphate Deposition Disease (CPPD) diagnosis but the prevalence of joint calcifications at imaging in CPPD patients has not been thoroughly assessed.

Objectives:

This systematic literature review (SLR) is aimed to estimate the prevalence of calcium crystal deposition in peripheral joints by imaging in suspected or definite CPPD patients to establish relevant joints for CPPD monitoring

Methods:

After defining PICOs, Pubmed and Embase were searched from inception to October 2020 for identifying studies that evaluated the use of Conventional Radiography (CR), Ultrasound (US), Computed Tomography (CT) and Dual Energy Computed Tomography (DECT) in detecting calcifications at peripheral joints in patients with defined or probable CPPD. Search strategies based on MeSH terms and free text were applied. Six reviewers independently screened titles and abstracts, eligible article full texts were evaluated for inclusion and data extraction.

Results:

The SLR identified 1149 manuscripts. 524 papers entered in the full text evaluation and 181 articles were finally included. Considering excluded abstracts and full texts, 23 and 17 were excluded as duplicate, 156 and 9 for language, 171 and 48 for population, 171 and 20 for intervention, 57 and 117 for outcome, 47 and 70 for study type and 76 for full text unavailability. Among included, 41 papers considered patients with definite CPPD with a total population of 1239 patients, 908 cases and 331 controls and 140 papers referred to patients with suspected CPPD with a total population of 26785 patients, 2896 affected by CPPD and 23889 controls. The results about all joints are summarized in the Table 1. In patients with definite diagnosis, knee and wrist are the joints with the highest prevalence of calcifications at all imaging types, followed by hip and acromion-clavicular joint while in patients with suspected CPPD, the knee is the most prevalent followed by the wrist, hip and ankle (only sites with more than 50 patients assessed considered). The hand joints are characterized by CPPD lowest prevalence at imaging. Bilateral imaging findings varies depending on the technique used, the site and the patient’s type.

Table 1.

Definite CPPD Diagnosis

KNEEWRISTHANDELBOWSHOULDERACHIPANKLEFOOTTMXRImaging positive cases/all cases330/584 57%214/409 52%43/158 27%54/212 25%65/249 26%37/84 44%140/293 48%30/255 12%15/59 25%0Cases positivebilaterally99/146 68%30/79 38%0/104/12 33%2/2 100%9/17 53%7/10 70%7/10 70%00USImaging positive cases/all cases155/252 62%86/118 75%4/42 9%2/2 100%0/304/30 13%47/80 59%30/255 12%15/59 25%0Cases positivebilaterally83/96 86%33/47 70%1/ 4 25%003/ 4 75%29/47 62%7/10 70%00CTImaging positive cases/all cases41/50 82%22/28 78%00000000Cases positivebilaterally27/30 90%000000000DECTImaging positive cases/all cases8/10 80%9/10 90%1/1 100%0000000Cases positivebilaterally001/1 100%0000000Suspected CPPD diagnosisKNEEWRISTHANDELBOWSHOULDERACHIPANKLEFOOTTMXRImaging positive cases/all cases1989/2442 81%549/1024 54%98/602 16%29/72 40%75/185 41%27/31 87%322/887 36%56/116 48%24/42 57%0Cases positive bilaterally611/1068 57%209/334 63%64/85 75%22/23 96%41/46 89%0/294/196 48%44/53 83%18/19 95%0USImaging positive cases/all cases241/261 93%125/185 68%2/39 5%1/1 100%4/12 33%02/2 100%27/78 35%8/37 22%0Cases positivebilaterally4/9 44%74/93 80%00000000CTImaging positive cases/all cases019/23 83%002/2 100%02/2 100%001/1 100%Cases positivebilaterally0000000001/1 100%DECTImaging positive cases/all cases1/1 100%2/2 100%00000000Cases positivebilaterally1/1 100%000000000

Table 1 For each joint, are summarized the ratio between positive joints and overall evaluated joints and the ratio between the joints positive bilaterally and overall joints evaluated bilaterally.

AC Acromion Clavicular, TM temporo mandibular

Conclusion:

According to the results of this SLR, knees and wrists could be the sentinel joints for CPPD detection by imaging.

Disclosure of Interests:

None declared.

POS1133 RELIABILITY OF CONVENTIONAL RADIOGRAPHY OF THE KNEE FOR THE ASSESSMENT OF CHONDROCALCINOSIS: AN ANCILLARY STUDY OF THE OMERACT ULTRASOUND – CPPD GROUP

Background:

Conventional Radiography (CR) has been widely used in the assessment of knee chondrocalcinosis (CC) and is still considered one of the most important diagnostic methods for the diagnosis. However, there are no studies on the reliability of CR for CC.

Objectives:

To assess the reliability of CR of the knee in the assessment of chondrocalcinosis (CC).

Methods:

This is an ancillary study of the Criterion Validity of Ultrasound in Calcium Pyrophosphate Deposition Disease (CPPD) study [1]. Consecutive patients with knee osteoarthritis (OA) that were planned for total knee replacement surgery were enrolled in 4 centres from Romania, Italy, USA and Mexico. All patients underwent CR of the knees taken maximum 6 months before surgery, in posterior-anterior weight baring and lateral projections. DICOM files of the radiographs were retrieved, anonymised and read independently by two musculoskeletal radiologists with experience in microcrystalline arthropathies. Each reader performed a second evaluation 3 weeks after the first one to calculate the inter- and intra-reader agreement. For each patient a dichotomic score was assigned (absence/presence of CC) at the level of the medial and lateral menisci, tibiofemoral hyaline cartilage, quadriceps and patella tendons, synovial membrane/joint capsule. The definitions of the ACR/EULAR taskforce for identification of CPPD in conventional radiography were used in this study [paper in preparation]. According to these definitions CPPD in CR appears as “linear or punctate opacities in the region of fibro- or hyaline articular cartilage/synovial membrane or joint capsule/within tendons or entheses that are distinct from denser, nummular radio-opaque deposits due to basic calcium phosphate deposition”. Cohen’s kappa was used to calculate the agreement between the two readers.

Results:

We enrolled 33 patients with knee OA (60.6% female, mean age 69yo ± 8). The kappa values of the inter-reader and intra-reader agreement in the various sites of the knee are indicated in Table 1. Inter-reader agreement was substantial at the level of both menisci but only moderate or fair at the other sites of assessment. This had a negative impact on the overall evaluation of the knee joint that proved to be unreliable (k of 0.16 – none to slight agreement) if all anatomical structures are included for assessment, and moderately reliable (kappa 0.41) when both menisci and hyaline cartilage are considered. On the other hand, intra-reader kappa values were substantial or higher in all sites (except for synovial membrane/joint capsule for one reader). The striking difference of the intra-reader compared to the inter-reader kappa values, highlight a different interpretation and application of the definitions used for most of the sites with the exception of the menisci.

Table 1.

kappa values for intra- and inter-reader agreement. Values from 0.01–0.20 are considered as none to slight agreement, 0.21–0.40 as fair, 0.41– 0.60 as moderate, 0.61–0.80 as substantial, and 0.81–1.00 as almost perfect agreement.

Medial meniscusLateral meniscusHyaline cartilageQuadriceps tendonPatellar tendonCapsule/ synoviaMenisci + cartilageEntire jointInter-reader0.670.710.340.47NA0.370.400.17Intra-reader 1st assessor0.670.900.840.65NA(insufficient number of categories)0.530.710.76Intra-reader 2nd assessor10.801110.910.860.94

Conclusion:

CR has been extensively used for diagnosis of OA and CPPD. The results of our study raise some concerns on the reliability of CR in identification of CPPD. Assessment of calcium crystals at the menisci level should be used for identification of CC as other sites of the knee seem to present low reliability.

References:

[1]Filippou G et al. Criterion validity of ultrasound in the identification of calcium pyrophosphate crystal deposits at the knee: an OMERACT ultrasound study. Ann Rheum Dis 2020. doi:10.1136/annrheumdis-2020-217998

Disclosure of Interests:

None declared.