Describing calcium pyrophosphate deposition: undoing the tower of Babel!

PURPOSE OF REVIEW: In 1977, McCarty astutely observed, 'The variety of names suggested for the condition associated with deposits of calcium pyrophosphate dihydrate crystals is exceeded only by the variations of its clinical presentation'. Fast forward to 2024, a standardized nomenclature for calcium pyrophosphate deposition (CPPD) is still lacking. This review aims to delineate the challenges in characterizing CPPD through nomenclature and imaging. RECENT FINDINGS: Despite the effort of nomenclature standardization in 2011 by the EULAR, confusion persists in the literature and clinical practice, with pseudo-forms and obscure abbreviations. The Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) has launched a project to redefine CPPD nomenclature and formulate a user-friendly language for effective communication with patients and other stakeholders. Additionally, recent advancements in imaging, have shed light on various aspects of the disorder. SUMMARY: Almost 60 years from the first description of a clinical manifestation related to calcium pyrophosphate crystals, a common language describing the disorder is still lacking. A redefined CPPD nomenclature, together with lay-friendly terminology, would significantly contribute to the uniformity of CPPD research, enhance public understanding and awareness and improve doctor-patient communication and therefore disease outcomes. Imaging can provide deep insights into CPPD elements, promoting comprehension of this disorder.

Systematic literature review to inform the EULAR recommendations for the use of imaging in crystal-induced arthropathies in clinical practice.

OBJECTIVE: To summarise current data regarding the use of imaging in crystal-induced arthropathies (CiAs) informing a European Alliance of Associations for Rheumatology task force. METHODS: We performed four systematic searches in Embase, Medline and Central on imaging for diagnosis, monitoring, prediction of disease severity/treatment response, guiding procedures and patient education in gout, calcium pyrophosphate dihydrate deposition (CPPD) and basic calcium phosphate deposition (BCPD). Records were screened, manuscripts reviewed and data of the included studies extracted. The risk of bias was assessed by validated instruments. RESULTS: For gout, 88 studies were included. Diagnostic studies reported good to excellent sensitivity and specificity of dual-energy CT (DECT) and ultrasound (US), high specificity and lower sensitivity for conventional radiographs (CR) and CT. Longitudinal studies demonstrated sensitivity to change with regard to crystal deposition by US and DECT and inflammation by US and structural progression by CR and CT. For CPPD, 50 studies were included. Diagnostic studies on CR and US showed high specificity and variable sensitivity. There was a single study on monitoring, while nine assessed the prediction in CPPD. For BCPD, 56 studies were included. There were two diagnostic studies, while monitoring by CR and US was assessed in 43 studies, showing a reduction in crystal deposition. A total of 12 studies with inconsistent results assessed the prediction of treatment response. The search on patient education retrieved two studies, suggesting a potential role of DECT. CONCLUSION: This SLR confirmed a relevant and increasing role of imaging in the field of CiAs.

2023 EULAR recommendations on imaging in diagnosis and management of crystal-induced arthropathies in clinical practice.

OBJECTIVE: To formulate evidence-based recommendations and overarching principles on the use of imaging in the clinical management of crystal-induced arthropathies (CiAs). METHODS: An international task force of 25 rheumatologists, radiologists, methodologists, healthcare professionals and patient research partners from 11 countries was formed according to the EULAR standard operating procedures. Fourteen key questions on the role of imaging in the most common forms of CiA were generated. The CiA assessed included gout, calcium pyrophosphate deposition disease and basic calcium phosphate deposition disease. Imaging modalities included conventional radiography, ultrasound, CT and MRI. Experts applied research evidence obtained from four systematic literature reviews using MEDLINE, EMBASE and CENTRAL. Task force members provided level of agreement (LoA) anonymously by using a Numerical Rating Scale from 0 to 10. RESULTS: Five overarching principles and 10 recommendations were developed encompassing the role of imaging in various aspects of patient management: making a diagnosis of CiA, monitoring inflammation and damage, predicting outcome, response to treatment, guided interventions and patient education. Overall, the LoA for the recommendations was high (8.46-9.92). CONCLUSIONS: These are the first recommendations that encompass the major forms of CiA and guide the use of common imaging modalities in this disease group in clinical practice.

Retention, safety and efficacy of off-label conventional treatments and biologics for chronic calcium pyrophosphate crystal inflammatory arthritis.

OBJECTIVES: Very little is known on the efficacy and safety of drugs for the management of chronic calcium pyrophosphate (CPP) crystal inflammatory arthritis. The objectives of this work were to describe the drugs used in the management of chronic CPP crystal inflammatory arthritis in expert European centres, and to examine treatment retention. METHODS: This was a retrospective cohort study. Charts from patients with a diagnosis of persistent inflammatory and/or recurrent acute CPP crystal arthritis were reviewed in seven European centres. Baseline characteristics were collected, and visits at months 3, 6, 12 and 24 included an assessment of treatment response and safety. RESULTS: One hundred and ninety-four treatments were initiated in 129 patients. Colchicine (used first-line in n = 73/86), methotrexate (used first-line in n = 14/36), anakinra (n = 27) and tocilizumab (n = 25) were the most prescribed treatments, while long-term corticosteroids, hydroxychloroquine, canakinumab and sarilumab were used occasionally. The 24-month on-drug retention was higher for tocilizumab (40%) than anakinra (18.5%) (P < 0.05), while the difference between colchicine (29.1%) and methotrexate (44.4%) was not statistically significant (P = 0.10). Adverse events led to 14.1% of colchicine discontinuations (100% of diarrhoea), 4.3% for methotrexate, 31.8% for anakinra and 20% for tocilizumab; all other discontinuations were related to insufficient response or losses to follow-up. Efficacy outcomes did not differ significantly between treatments throughout follow-up. CONCLUSION: Daily colchicine is the first-line therapy used in chronic CPP crystal inflammatory arthritis, which is considered efficient in a third to half of cases. Second-line treatments include methotrexate and tocilizumab, which have higher retention than anakinra.

Tailored exercise programmes for fibromyalgia: a clinical practical guide.

OBJECTIVES: To evaluate the role of exercise in the management of fibromyalgia syndrome (FM) by addressing its complex pathogenesis involving central sensitisation, autonomic dysfunction, inflammation, and neurological irregularities, and examining how exercise impacts symptom exacerbation caused by external stressors and comorbid conditions. METHODS: This review synthesises evidence from current literature focusing on the benefits of structured and personalised exercise programmes in FM management. It discusses the importance of specifying exercise type, intensity, frequency, duration, and progression tailored to individual patient needs and clinical objectives. RESULTS: Regular physical activity effectively mitigates core aetiopathogenetic mechanisms of FM and improves associated conditions such as stress and obesity. It also provides benefits for preventing other chronic diseases, enhancing well-being, and promoting healthy ageing. Structured and personalised exercise programmes that start with a low-demand protocol and gradually increase exercise volume are most beneficial, by improving patient compliance and reducing the risk of adverse effects. CONCLUSIONS: Effective management of FM requires a patient-centred approach integrating both pharmacological and non-pharmacological treatments, with exercise playing a pivotal role. Personalised exercise prescriptions that consider FM patients' specific needs and limitations are crucial for optimising treatment outcomes and enhancing quality of life.

How can ultrasonography help in the management of CPPD? From diagnosis to clinical subset identification.

PURPOSE OF REVIEW: Clinical manifestations of calcium pyrophosphate deposition (CPPD) disease are quite heterogeneous, ranging from asymptomatic presentation to severe forms of arthritis. In recent years, imaging, particularly ultrasound (US) has gained a central role for the diagnosis of CPPD. However, many questions are still open. Aim of this review is to present how US could be a key tool in the diagnosis and assessment of CPPD and for the identification of subsets of the disease. RECENT FINDINGS: awareness and research interest around CPPD is increasing in the recent years, as several international taskforces are working on the validation of outcome measures and classification criteria for CPPD, but many pieces of the puzzle are still missing. Recent studies demonstrated that CPPD is an underdiagnosed disease, frequently misdiagnosed as rheumatoid arthritis or polymyalgia rheumatica. US has been increasingly used in the past decade for the diagnosis of CPPD and US definitions have been validated by the OMERACT US working group in the recent years, making of US a valuable tool for diagnosis. SUMMARY: The most challenging aspects of CPPD are the differential diagnosis with other form of arthritis of the elderly, and the classification of patients in clinical subsets. In this review, we will present the available data for the use of US in the diagnosis of CPPD and we will provide a mainly experienced-based approach to the potential role of the technique in differential diagnosis and phenotypization of patients.

The 2023 ACR/EULAR classification criteria for calcium pyrophosphate deposition disease.

OBJECTIVE: Calcium pyrophosphate deposition (CPPD) disease is prevalent and has diverse presentations, but there are no validated classification criteria for this symptomatic arthritis. The American College of Rheumatology (ACR) and EULAR have developed the first-ever validated classification criteria for symptomatic CPPD disease. METHODS: Supported by the ACR and EULAR, a multinational group of investigators followed established methodology to develop these disease classification criteria. The group generated lists of candidate items and refined their definitions, collected de-identified patient profiles, evaluated strengths of associations between candidate items and CPPD disease, developed a classification criteria framework, and used multi-criterion decision analysis to define criteria weights and a classification threshold score. The criteria were validated in an independent cohort. RESULTS: Among patients with joint pain, swelling, or tenderness (entry criterion) whose symptoms are not fully explained by an alternative disease (exclusion criterion), the presence of crowned dens syndrome or calcium pyrophosphate crystals in synovial fluid are sufficient to classify a patient as having CPPD disease. In the absence of these findings, a score>56 points using weighted criteria, comprising clinical features, associated metabolic disorders, and results of laboratory and imaging investigations, can be used to classify as CPPD disease. These criteria had a sensitivity of 92.2% and specificity of 87.9% in the derivation cohort (190 CPPD cases, 148 mimickers), whereas sensitivity was 99.2% and specificity was 92.5% in the validation cohort (251 CPPD cases, 162 mimickers). CONCLUSION: The 2023 ACR/EULAR CPPD disease classification criteria have excellent performance characteristics and will facilitate research in this field.

Relationship between the prevalence of subclinical tenosynovitis and treatment in patients with RA in clinical remission: STARTER study.

OBJECTIVE: This study is a sub-analysis from the patient cohort of the STARTER (Sonographic Tenosynovitis Assessment in RheumaToid arthritis patiEnts in Remission) study. The aim was to evaluate differences in ultrasound-detected joint and/or tendon involvement between patients receiving therapies based on a combination of conventional synthetic DMARDs (csDMARDs) and biologic DMARDs (bDMARDs) and those who were treated with either csDMARDs or bDMARDs in monotherapy. MATERIAL AND METHODS: Four hundred and twenty-seven consecutive patients with a diagnosis of RA were recruited between October 2013 and June 2014. They were divided into three subgroups based on their therapy at baseline: patients with bDMARD in monotherapy, patients with csDMARD in monotherapy and patients in combination therapy (csDMARD + bDMARD). At baseline, 6 months and 12 months, a clinical examination (28 joint count) and an ultrasound evaluation were performed in each patient. A score of grey-scale (GS) and power Doppler (PD) synovitis and tenosynovitis was calculated based on the OMERACT scoring systems. RESULTS: Two hundred and fifty-six patients completed the observation period: 48 patients from the bDMARD group (18.75%), 152 patients from the csDMARD group (59.38%) and 56 patients from csDMARD + bDMARD group (21.88%). The analysis showed that GS tenosynovitis and PD tenosynovitis are better controlled in combination therapy than they are with csDMARD alone (P = 0.025 and P = 0.047, respectively); for PD synovitis, there was a better response in those who were treated with the combination therapy when compared with the patients receiving csDMARD (P = 0.01) or bDMARD (P = 0.02) alone. CONCLUSIONS: The analysis showed a lower prevalence of subclinical inflammatory manifestations detected with ultrasound imaging in those patients treated with the combination therapy than in those in monotherapy.

Diagnosis of calcium pyrophosphate crystal deposition disease by ultrasonography: how many and which sites should be scanned?

OBJECTIVE: To develop the optimal US scanning protocol for the diagnosis of CPPD disease. METHODS: In this cross-sectional study, consecutive patients with a crystal-proven diagnosis of CPPD disease, and age-, sex-matched disease controls and with a negative synovial fluid analysis were prospectively enrolled in two Italian Institutions. Four rheumatologists, blinded to patients' clinical details, performed US examinations using a standardised scanning protocol including 20 joints (shoulders, elbows, wrists, metacarpophalangeal joints from 2nd to 5th fingers, hips, knees, ankles). CPPD was identified as presence/absence, according to the OMERACT definitions. Reduced US scanning protocols were developed by selecting the most informative joints to be imaged by US using the LASSO technique. Patients were randomly divided into training and validation sets. Their diagnostic accuracy was tested comparing the area under the ROC curves. RESULTS: 204 participants were enrolled: 102 with CPPD disease and 102 disease controls [age (mean±standard deviation) 71.3 ± 12.0 vs 71.1 ± 13.5 years, female: 62.8% vs 57.8%].The median number of joints with US evidence of CPPD was 5 (IQR: 4-7) and 0 (IQR: 0-1) in patients with CPPD disease and controls, respectively (p< 0 01).The detection of CPPD in ≥ 2 joints using a reduced scanning protocol (bilateral assessment of knees, wrists, and hips) showed a sensitivity of 96.7% (95%CI: 82.8-99.9) and a specificity of 100 (95%CI: 88.8-100.0) for the diagnosis of CPPD disease and had good feasibility [(mean±standard deviation) 12.5 ± 5.3 min]. CONCLUSION: Bilateral US assessment of knees, wrists, and hips had excellent accuracy and good feasibility for the diagnosis of CPPD disease.

Novel insights into the management of rheumatoid arthritis: one year in review 2023.

New evidence from 2022 slightly changed some perspectives for rheumatoid arthritis (RA) management. Real-world data on the efficacy and safety of disease-modifying anti-rheumatic drugs strengthened the importance of tailoring treatment decisions based on patient characteristics. Moreover, the research of response biomarkers to therapy underlined the need for precision medicine and remote care applications showed an innovative outlook that supports a patient-centred approach. New developments in vaccinations led to the release of updated guidelines and to a consistent improvement in the prevention of vaccine-preventable infections. New literature data also reconsidered drug management in RA-associated interstitial lung disease and pregnancy. In this paper, the reviewers aim to present the most relevant studies published during the last year in the field of RA management.

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.

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 was to develop and assess the reliability of a consensus-based semiquantitative colour Doppler US scoring system for pathologic salivary gland vascularization in patients with primary Sjögren's syndrome (pSS). METHODS: Using the Delphi method, a colour Doppler 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 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 kappa values (95% CI) of 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 kappa = 0.84 (0.73, 0.92) and 0.70 (0.64, 0.76), respectively. CONCLUSION: The consensus-based colour Doppler US 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.

Novel insights into the management of rheumatoid arthritis: one year in review 2022.

New evidence for the treatment of rheumatoid arthritis (RA) has emerged during the last year. Specifically, updated guidelines on pharmacological and non-pharmacological management of RA have emphasised the necessity of global patient's care, and have shifted the role of some older drugs, such as glucocorticoids and methotrexate. In addition, the long-term safety of Janus kinase inhibitors was investigated and reinforced. With respect to the coronavirus-19 pandemic, reassuring data on the efficacy and safety of vaccinations in the RA population were acquired, as well as on the potential role of telemedicine in RA management. Machine learning prediction models and biomarkers development have emerged as promising innovations in the area of precision/personalised medicine, appearing to encourage future expansion.In this narrative review, the authors aim to give their specific point of view on the most relevant and potentially impacting novelties published during 2021 and early 2022 in the context of RA management.

Criterion validity of ultrasound in the identification of calcium pyrophosphate crystal deposits at the knee: an OMERACT ultrasound study.

OBJECTIVE: To evaluate the discriminatory ability of ultrasound in calcium pyrophosphate deposition disease (CPPD), using microscopic analysis of menisci and knee hyaline cartilage (HC) as reference standard. METHODS: Consecutive patients scheduled for knee replacement surgery, due to osteoarthritis (OA), were enrolled. Each patient underwent ultrasound examination of the menisci and HC of the knee, scoring each site for presence/absence of CPPD. Ultrasound signs of inflammation (effusion, synovial proliferation and power Doppler) were assessed semiquantitatively (0-3). The menisci and condyles, retrieved during surgery, were examined microscopically by optical light microscopy and by compensated polarised microscopy. CPPs were scored as present/absent in six different samples from the surface and from the internal part of menisci and cartilage. Ultrasound and microscopic analysis were performed by different operators, blinded to each other's findings. RESULTS: 11 researchers from seven countries participated in the study. Of 101 enrolled patients, 68 were included in the analysis. In 38 patients, the surgical specimens were insufficient. The overall diagnostic accuracy of ultrasound for CPPD was of 75%-sensitivity of 91% (range 71%-87% in single sites) and specificity of 59% (range 68%-92%). The best sensitivity and specificity were obtained by assessing in combination by ultrasound the medial meniscus and the medial condyle HC (88% and 76%, respectively). No differences were found between patients with and without CPPD regarding ultrasound signs of inflammation. CONCLUSION: Ultrasound demonstrated to be an accurate tool for discriminating CPPD. No differences were found between patents with OA alone and CPPD plus OA regarding inflammation.

The two faces of the same medal or maybe not? Comparing osteoarthritis and calcium pyrophosphate deposition disease: a laboratory and ultrasonographic study.

OBJECTIVES: Osteoarthritis (OA) and calcium pyrophosphate deposition disease (CPPD) are frequently associated but the real relation between these diseases is not still understood. The aim of this paper is to investigate the characteristics in terms of inflammation, anatomical changes and synovial fluid (SF) features in knees of patients with OA and CPPD. METHODS: Consecutive patients older than 55 years with knee pain and swelling were enrolled. All patients underwent a complete clinical examination, a US examination of the affected joint, arthrocentesis of the knee and analysis of synovial fluid, including dosing of inorganic ions and number of crystals. The gold standard for the diagnosis was the microscopic analysis of the SF. RESULTS: Sixty-seven patients were enrolled, 25 affected by OA and 42 by CPPD. At US, a significantly higher amount of effusion and synovitis was identified in patients with CPPD but there were no significant differences regarding structural changes. At the SF analysis, the white blood cell (WBC) count was higher in patients with CPPD who also presented a higher number of polymorphonuclear cells and a lower number of monocytes. Regarding the inorganic ion concentration, the statistical analysis did not reveal any differences. The number of crystals in the SF, correlated with a larger effusion, higher grade of synovitis and a higher WBC count. CONCLUSIONS: A higher degree of inflammation was found in patients with CPPD. The findings suggest that longitudinal studies would be useful to better understand the evolution of the diseases and highlight the need for different treatment strategies.

Utility of Ultrasound and Dual Energy CT in Crystal Disease Diagnosis and Management.

PURPOSE OF REVIEW: The objective of this review is to critically discuss the latest evidence on the use of ultrasound and dual energy computed tomography (DECT) for the assessment of microcrystalline arthritis. RECENT FINDINGS: Both techniques have been included in the classification and diagnostic criteria for gout, while only ultrasound appears in the diagnostic recommendations for CPPD. Regarding the management of the diseases, there is encouraging evidence for the use of both techniques for the follow-up of gout patients, while very few or null data are available for CPPD. Ultrasound has been adequately validated for the diagnosis of CPPD, while some issues have still to be clarified regarding gout. DECT has also demonstrated to be accurate for gout diagnosis, but very few data are available regarding CPPD. Future research should aim to improve the reliability of both techniques and to create scoring systems for a more accurate follow-up of patients.

Video clip assessment of a salivary gland ultrasound scoring system in Sjögren's syndrome using consensual definitions: an OMERACT ultrasound working group reliability exercise.

OBJECTIVE: To develop ultrasound (US) definitions and a US novel scoring system for major salivary gland (SG) lesions in patients with primary Sjögren's syndrome (pSS) and to test their intrareader and inter-reader reliability using US video clips. METHODS: Twenty-five rheumatologists were subjected to a three-round, web-based Delphi process in order to agree on (1) definitions and scanning procedure of salivary gland ultrasonography (SGUS): parotid, submandibular and sublingual glands (PG, SMG and SLG); (2) definitions for the elementary SGUS lesions in patients with Sjögren's syndrome; (3) scoring system for grading changes. The experts rated the statements on a 1-5 Likert scale. In the second step, SGUS video clips of patients with pSS and non-pSS sicca cases were collected containing various spectrums of disease severity followed by an intrareader and inter-reader reliability exercise. Each video clip was evaluated according to the agreed definitions. RESULTS: Consensual definitions were developed after three Delphi rounds. Among the three selected SGs, US assessment of PGs and SMGs was agreed on. Agreement was reached to score only greyscale lesions and to focus on anechoic/hypoechoic foci in a semiquantitative matter or, if not possible on a qualitatively (present/absent) evaluation of fatty or fibrous lesions. Intrareader reliability for detecting and scoring these lesions was excellent (Cohen's kappa 0.81) and inter-reader reliability was good (Light's kappa 0.66). CONCLUSION: New definitions for developing a novel semiquantitative US score in patients with pSS were developed and tested on video clips. Inter-reader and intrareader reliabilities were good and excellent, respectively.

Gout, Hyperuricaemia and Crystal-Associated Disease Network (G-CAN) consensus statement regarding labels and definitions of disease states of gout.

OBJECTIVE: There is a lack of standardisation in the terminology used to describe gout. The aim of this project was to develop a consensus statement describing the recommended nomenclature for disease states of gout. METHODS: A content analysis of gout-related articles from rheumatology and general internal medicine journals published over a 5-year period identified potential disease states and the labels commonly assigned to them. Based on these findings, experts in gout were invited to participate in a Delphi exercise and face-to-face consensus meeting to reach agreement on disease state labels and definitions. RESULTS: The content analysis identified 13 unique disease states and a total of 63 unique labels. The Delphi exercise (n=76 respondents) and face-to-face meeting (n=35 attendees) established consensus agreement for eight disease state labels and definitions. The agreed labels were as follows: 'asymptomatic hyperuricaemia', 'asymptomatic monosodium urate crystal deposition', 'asymptomatic hyperuricaemia with monosodium urate crystal deposition', 'gout', 'tophaceous gout', 'erosive gout', 'first gout flare' and 'recurrent gout flares'. There was consensus agreement that the label 'gout' should be restricted to current or prior clinically evident disease caused by monosodium urate crystal deposition (gout flare, chronic gouty arthritis or subcutaneous tophus). CONCLUSION: Consensus agreement has been established for the labels and definitions of eight gout disease states, including 'gout' itself. The Gout, Hyperuricaemia and Crystal-Associated Disease Network recommends the use of these labels when describing disease states of gout in research and clinical practice.

Identification of calcium pyrophosphate deposition disease (CPPD) by ultrasound: reliability of the OMERACT definitions in an extended set of joints-an international multiobserver study by the OMERACT Calcium Pyrophosphate Deposition Disease Ultrasound Subtask Force.

OBJECTIVES: To assess the reliability of the OMERACT ultrasound (US) definitions for the identification of calcium pyrophosphate deposition disease (CPPD) at the metacarpal-phalangeal, triangular fibrocartilage of the wrist (TFC), acromioclavicular (AC) and hip joints. METHODS: A web-based exercise and subsequent patient-based exercise were carried out. A panel of 30 OMERACT members, participated at the web-based exercise by evaluating twice a set of US images for the presence/absence of CPPD. Afterwards, 19 members of the panel met in Siena, Italy, for the patient-based exercise. During the exercise, all sonographers examined twice eight patients for the presence/absence of CPPD at the same joints. Intraoberserver and interobserver kappa values were calculated for both exercises. RESULTS: The web-based exercise yielded high kappa values both in intraobserver and interobserver evaluation for all sites, while in the patient-based exercise, inter-reader agreement was acceptable for the TFC and the AC. TFC reached high interobserver and intraobserver k values in both exercises, ranging from 0.75 to 0.87 (good to excellent agreement). AC reached moderate kappa values, from 0.51 to 0.85 (moderate to excellent agreement) and can readily be used for US CPPD identification. CONCLUSIONS: Based on the results of our exercise, the OMERACT US definitions for the identification of CPPD demonstrated to be reliable when applied to the TFC and AC. Other sites reached good kappa values in the web-based exercise but failed to achieve good reproducibility at the patient-based exercise, meaning the scanning method must be further refined.