Impact of COVID-19 on TB epidemiology in South Korea

SETTING: Five referral hospitals, South Korea.OBJECTIVE: To assess epidemiological changes in TB before and during the COVID-19 pandemic.DESIGN: This was a multicentre cohort study of 3,969 patients diagnosed with TB.RESULTS: We analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years, P < 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019; P = 0.005).CONCLUSIONS: The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.

Inverse Laplace transformation analysis of stretched exponential relaxation

We investigate the effectiveness of the Inverse Laplace Transform (ILT) analysis method to extract the distribution of relaxation rates from nuclear magnetic resonance data with stretched exponential relaxation. Stretched-relaxation is a hallmark of a distribution of relaxation rates, and an analytical expression exists for this distribution for the case of a spin-1/2 nucleus. We compare this theoretical distribution with those extracted via the ILT method for several values of the stretching exponent and at different levels of experimental noise. The ILT accurately captures the distributions for β≲0.7, and for signal to noise ratios greater than ∼40; however the ILT distributions tend to introduce artificial oscillatory components. We further use the ILT approach to analyze stretched relaxation for spin I>1/2 and find that the distributions are accurately captured by the theoretical expression for I=1/2. Our results provide a solid foundation to interpret distributions of relaxation rates for general spin I in terms of stretched exponential fits.

The mucin protein MUCL1 regulates melanogenesis and melanoma genes in a manner dependent on threonine content

Background

The regulation of melanogenesis has been investigated as a long‐held aim for pharmaceutical manipulations with denotations for malignancy of melanoma. Mucins have a protective function in epithelial organs; however, in the most outer organ, the skin, the role of mucins has not been studied enough.

Objectives

Our initial hypothesis developed from the identification of correlations between pigmentation and expressions of skin mucins, particularly those existing in skin tissue. We aimed to investigate the action of mucins in human melanocytic cells.

Materials and methods

The expression of mucin proteins in human skin was investigated using microarray data from the Human Protein Atlas consortium (HPA) and the Genotype‐Tissue Expression consortium (GTEx) database. Mucin expression was measured at RNA and protein levels in melanoma cells. The findings were further validated and confirmed by analysis of independent experiments.

Results

We found that the several mucin proteins showed expression in human skin cells and among these, mucin‐like protein 1 (MUCL1) showed the highest expression and also clear negative correlation with melanogenesis in epidermal melanocytes. We confirmed the correlations between melanogenesis and MUCL1 by revealing negative correlations in melanocytes with different melanin production, resulting from increased composition of threonine, mucin‐conforming amino acid, and increased autophagy‐related forkhead‐box O signalling. Furthermore, threonine itself affects melanogenesis and metastatic activity in melanoma cells.

Conclusions

We identified a significant association between MUCL1 and threonine with melanogenesis and metastasis‐related genes in melanoma cells. Our results define a novel mechanism of mucin regulation, suggesting diagnostic and preventive roles of MUCL1 in cutaneous melanoma.

Whatis already known about this topic?

Despite considerable advances in radioactive therapeutics or chemotherapeutic approaches for the treatment of abnormal melanogenesis, there are still many caveats to delivery, effectiveness and safety, thus leaving a necessity for more immediate pharmaceutical targets.

Mucins have protective and chemical barrier functions in epithelial organs; however, in the skin, mucin has scarce expression and is known only as a diagnostic aid in skin disorders such as mucinosis.

Whatdoes this study add?

We provide detailed analysis demonstrating the potential of mucin‐like protein 1 (MUCL1), which showed negative correlations in melanocytes with different melanin production, resulting from increased composition of threonine and increased autophagy‐related forkhead‐box O signalling in epidermal melanocytes and melanoma cells.

We established that through an alternative pathway for MUCL1 biosynthesis, threonine supplementation recovers MUCL1 levels in melanoma. Changes, brought on by the essential amino acid threonine, resulted in substantial modulations in melanogenesis and reduced metastasis‐related genes.

Whatis the translational message?

This study demonstrates for the first time that the mucin protein of skin cells is compounded by distorted mucin homeostasis, with major effects on melanogenesis and metastasis‐related genes in melanoma.

We anticipate that these novel findings will be of keen interest to the community of scientists and medical practitioners examining skin dysfunction.

Linked Comment: C. Casalou and D.J. Tobin. Br J Dermatol 2022; 186:388–389.

Plain language summary available online

Rising rates of hospital-onset Klebsiella spp. and Pseudomonas aeruginosa bacteraemia in NHS acute trusts in England: a review of national surveillance data, August 2020-February 2021

Increases in hospital-onset Klebsiella spp. and Pseudomonas aeruginosa bacteraemia rates in England were observed between August 2020 and February 2021 to the highest levels recorded since the start of mandatory surveillance in April 2017. Cases were extracted from England's mandatory surveillance database for key Gram-negative bloodstream infections. Incidence rates for hospital-onset bacteraemia cases increased from 8.9 (N=255) to 14.9 (N=394) per 100,000 bed-days for Klebsiella spp. [incidence rate ratio (IRR) 1.7, P<0.001], and from 4.9 (N=139) to 6.2 (N=164) per 100,000 bed-days for P. aeruginosa (IRR 1.3, P<0.001) (August 2020-February 2021). These incidence rates were higher than the average rates observed during the same period in the previous 3 years. These trends coincided with an increase in the percentage of hospital-onset bacteraemia cases that were also positive for severe acute respiratory syndrome coronavirus-2.

POS1148 RISK FACTORS FOR POLYARTICULAR GOUT FLARES—ANALYSIS OF A LONGITUDINAL ONLINE GOUT FOLLOW-UP STUDY

Background:

There are known and established risk factors for gout flares; however, no study has examined the factors specifically associated with a polyarticular gout flare.

Objectives:

Evaluate risk factors of a polyarticular gout flare in a longitudinal study of individuals with gout.

Methods:

We used data from the Boston Online Gout Study, a longitudinal internet-based case-crossover study, where gout patients with at least one flare within the past year were enrolled across the US. Participants (N=903) were followed prospectively for 1 year via the internet to collect information on gout flares and related data including number and specific joints involved, medical comorbidities, diet, exercise and medications.

A polyarticular gout flare was defined as having 3 or more joints involved during a patient-reported flare period. Individuals with at least one flare (to determine flare pattern) during follow-up were included in the analysis. Univariable associations were first assessed to determine factors were associated with polyarticular joint flares. was used to adjust for confounders. When assessing the association of each risk factor with prevalent polyarticular joint involvement, we used multivariable logistic regression, adjusting specific confounders guided by causal diagram.

Results:

There were 724 participants with at least one flare with a mean and median age of 55 years. The cohort was 78% male and 89% White with a mean gout disease duration of 8.1 years (median 5). 197 (27%) had a polyarticular gout flare. In univariable analysis (Table 1), female sex, osteoarthritis, obesity, heart failure, hypertension, chronic kidney disease and gout related medication use were each associated with higher odds of polyarticular gout flare, whereas higher education, alcohol use at study enrollment and aspirin use were associated with lower odds. In multivariable analysis, obesity, osteoarthritis and heart failure remained associated with a higher odds of polyarticular gout flare, whereas education remained inversely associated.

Conclusion:

In this prospective cohort of gout patients, obesity, heart failure and osteoarthritis were independently associated with higher odds for polyarticular gout flares. Female sex was also positively associated, whereas higher education was protective. The positive association with gout-related medications likely reflects residual confounding by indication. If confirmed, these findings would help identify those at risk for polyarticular flares to help improve clinical care.

Table 1.

Associations with Polyarticular Gout Flare (≥ 3 joints)

Risk FactorUnivariable OR (95% CI)Age- and Sex-Adjusted OR (95% CI)Multivariable OR* (95% CI)Age ≥ 55 years (vs < 55)0.82 (0.59,1.14)0.77 (0.56,1.08)0.70 (0.49,1.01)Female Sex1.51 (1.04,2.22)1.55 (1.03,2.32)1.21 (0.78,1.88)White Race (vs Non-White)0.89 (0.54,1.48)0.93 (0.56,1.54)0.75 (0.44,1.28)Education (vs High School or Less)Some college0.63 (0.37,1.07)0.53 (0.37,1.07)0.68 (0.39,1.17)College0.45 (0.25,0.78)0.46 (0.26,0.81)0.49 (0.27,0.88)Post-graduate0.42 (0.25,0.72)0.44 (0.26,0.76)0.48 (0.28,0.84)Body Mass Index (kg/m2) at Enrollment (vs < 25)25-29.91.69 (0.85,3.33)1.77 (0.89,3.51)1.82 (0.90,3.65)≥ 302.38 (1.24,4.58)2.30 (1.19,4.43)2.19 (1.12,4.28)Alcohol Use at Enrollment (vs. Non-Use)0.60 (0.40,0.89)0.60 (0.40,0.91)**Gout Duration ≥ 5 years (vs < 5)0.85 (0.61,1.18)0.93 (0.66,1.31)0.95 (0.66,1.35)Presence of Comorbidities at Enrollment (vs Absence)Osteoarthritis2.35 (1.45,3.81)2.37 (1.43,3.95)2.39 (1.42,4.04)Heart Failure2.06 (1.11,3.81)2.21 (1.17,4.17)2.03 (1.06,3.91)Hypertension1.61 (1.08,2.40)1.69 (1.10,2.60)**Chronic Kidney Disease1.97 (1.03,3.78)2.11 (1.09,4.11)**Medication Use at Enrollment (vs No Use)Allopurinol1.58 (1.13,2.22)1.59 (1.13,2.23)**Diuretics1.53 (1.06,2.21)1.59 (1.06,2.38)**Oral Steroids2.21 (1.16,4.18)2.26 (1.19,4.31)**Aspirin0.68 (0.47,0.98)0.72 (0.49,1.07)**

*Mutually adjusted for the variables in this column

**Not included in model

Acknowledgements:

NIH P50AR060772.

Disclosure of Interests:

Jonathan Dau: None declared, Natalie McCormick: None declared, Sarah Stratton: None declared, Chio Yokose: None declared, Clara Chen: None declared, Tuhina Neogi Shareholder of: Lilly, EMD Merck Serono, Novartis, Regeneron, Pfizer/Lilly, David Hunter Shareholder of: Pfizer, Lilly, Merck Serono, Kenneth Saag Consultant of: Arthrosi, Horizon Therapeutics plc, Atom Bioscience, LG Pharma, Takeda, Mallinkrodt, SOBI, Grant/research support from: Horizon Therapeutics plc, Shanton, SOBI, Yuqing Zhang: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon.

POS1150 ANATOMICAL LOCATIONS AND CORRELATES OF CALCIUM PYROPHOSPHATE CRYSTAL DEPOSITS OF THE SPINE – PATHOLOGIC EXAMINATION OF 77 SURGICAL CASES

Background:

Spinal involvement in calcium pyrophosphate deposition disease (CPPD) is thought to be a rare occurrence and is seen infrequently as crowned dens syndrome. Furthermore, data on anatomical locations and correlates of calcium pyrophosphate (CPP) deposits in spinal CPPD are scarce.

Objectives:

To describe the anatomical locations and correlates of pathologically confirmed CPPD of the spine.

Methods:

Consecutive patients with spinal CPPD were identified via retrospective chart review of individuals who underwent spine surgery for intractable chronic neck or back pain at Massachusetts General Hospital between 2009 and 2014. These deposits and surrounding anatomical structures were surgically resected and confirmed to have calcium pyrophosphate deposition upon pathologic review. We reviewed musculoskeletal imaging (CT, MRI, XR) and laboratory data from these pathologically confirmed cases.

Results:

From April 2009 to August 2014, we identified 77 individuals with pathologically confirmed CPPD of the spine. The mean age was 68 years; 41 (53%) were female; mean BMI was 28.7. Calcium pyrophosphate (CPP) was grossly identified intraoperatively by the surgeon in 38 cases (50%), typically as “chalky white deposits” (Figure 1). CPP deposits were seen most frequently in the ligamentum flavum (23%) and intervertebral disc (23%), followed by other less common locations (Table 1). Imaging findings in the soft tissue or intervertebral disc suggestive of CPPD were found in 5 cases (6%), whereas findings of spinal canal narrowing, facet arthropathy, or ligamentum flavum thickening were eventually correlative with CPP deposits in pathologic specimens. Only 7 (9%) experienced a prior episode of acute CPP arthritis (pseudogout). Chondrocalcinosis on x-ray was seen in 26 cases (34%), most commonly in the wrist and/or knees. Osteoarthritis was present in all spinal imaging, and 65% had comorbid scoliosis. Laboratory abnormalities associated with secondary causes of CPPD (hypercalcemia, hypomagnesemia, hyperparathyroidism) were not seen with spinal CPPD.

Conclusion:

Spinal CPPD may occur more frequently than previously perceived. The ligamentum flavum and intervertebral discs were common anatomical locations for spinal CPPD. Advanced imaging of the spine showed low sensitivity for detecting spinal CPPD. Only a small minority had typical peripheral joint involvement or imaging with peripheral joint chondrocalcinosis. Thus, without pathologic confirmation, the vast majority of cases would remain unidentified. These findings call for the need to seek pathologic confirmation to determine the robust epidemiology and also raise the potential role for preoperative CPPD treatment.

Table 1.

Spinal Anatomic Locations of Pathologically Confirmed CPPD

Spinal Anatomic LocationNo. of Sites (%)*ligamentum flavum29 (23)Intervetebral Disc28 (23)Other Location19 (15)Posterior Elements18 (15)Facet14 (11)Synovium8 (6)Interspinous Ligament3 (2)Subarticular/Lateral Recess2 (2)Fibrocartilaginous Tissue1 (1)Inner Spine1 (1)Other Ligament1 (1)

*Some patients had more than one anatomic location where CPP was isolated

Figure 1.

Gross visualization of calcium pyrophosphate deposition (black arrow)

Disclosure of Interests:

Jonathan Dau: None declared, Gary Ho: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon, Joseph Schwab: None declared, Minna Kohler Speakers bureau: Eli Lily, Consultant of: Novartis.

OP0005 DIETARY HYPERINSULINEMIC POTENTIAL AND RISK OF INCIDENT GOUT: 3 PROSPECTIVE COHORT STUDIES OF US MEN AND WOMEN

Background:

Gout and the metabolic (insulin resistance) syndrome frequently coexist. Intravenous insulin has been shown to raise serum urate (SU) levels in physiologic studies and a Mendelian Randomization study also showed a causal role of insulin on the risk of gout. However, it is unknown whether habitual hyperinsulinemic dietary intake confers gout risk.

Objectives:

Prospectively examine the relation between two distinct insulin-related dietary indices and risk of incident gout in three large cohorts of US women and men over 30 years.

Methods:

We studied 164,090 women from Nurses Health Study I (1986-2016) and II (1989-2017) and 40,598 men from Health Professionals Follow-up Study (1986-2016), who were free of gout at baseline. Dietary intake and covariates were assessed by validated questionnaires every 4 years. Insulinemic potential of diet was evaluated using 1) food-based empirical dietary index for hyperinsulinemia (EDIH) score that was pre-defined based on circulating C-peptide levels1 and reflects insulin resistance;2 and 2) dietary insulin index (DII), which reflects transient, postprandial insulin secretion.2 We assigned EDIH and DII scores for each participant, adjusted for total energy intake, and prospectively examined the association between scores and incident gout (using ACR survey criteria for gout3), adjusting for potential confounders.

Results:

We ascertained 2,874 incident gout cases over 5,124,490 person-years of follow-up. In pooled multivariable-adjusted analyses, those in the highest EDIH quintile had 1.76-times (95% CI: 1.56 to 1.99) higher gout risk, compared with the lowest (Table 1). This attenuated with further adjustment for BMI (a likely causal intermediate) but remained positive (RR 1.30, 1.15 to 1.48). DII scores were inversely associated with gout risk (RR 0.66, 0.58 to 0.74) (Table 1).

Table 1.

Risk Ratio (95% CI) of Gout According to Quintiles of Insulin-Related Dietary Index

EDIH (measure of insulin resistance)Q1:lowest circulating insulin levelsQ2Q3Q4Q5:highest circulating insulin levelsP for trendN cases430482598631733Person-years1,025,1291,025,2851,025,5741,025,3011,023,651Age-adjusted RR1.00 (Ref)1.13 (1.00-1.29)1.43 (1.26-1.61)1.53 (1.36-1.73)1.85 (1.64-2.09)<.0001MV-Adjusted*RR1.00 (Ref)1.11 (0.98-1.27)1.39 (1.22-1.57)1.47 (1.30-1.67)1.76 (1.56-1.99)<.0001MV-Adjusted**RR (+ BMI)1.00 (Ref)1.03 (0.90-1.17)1.21 (1.06-1.37)1.21 (1.07-1.37)1.30 (1.15-1.48)<.0001Dietary Insulin Index (measure of transient, post-prandial secretion and sensitivity)Q1:lowest insulin sensitivityQ2Q3Q4Q5:greatest insulin sensitivityP for trendN cases783611527498455Person-years1,024,7631,025,7301,025,0751,025,5381,023,834Age-adjusted RR1.00 (Ref)0.79 (0.71-0.88)0.69 (0.62-0.77)0.65 (0.58-0.73)0.59 (0.53-0.66)<.0001MV-Adjusted*RR1.00 (Ref)0.79 (0.71-0.88)0.69 (0.62-0.77)0.66 (0.59-0.74)0.60 (0.53-0.67)<.0001MV-Adjusted**RR (+ BMI)1.00 (Ref)0.78 (0.70-0.87)0.69 (0.62-0.77)0.67 (0.60-0.75)0.66 (0.58-0.74)<.0001

*Multivariable (MV) models adjusted for age (month), White race, smoking, menopause (women only), hormone use (women only), physical activity, history of hypertension, and diuretic use **MV + BMI models further adjusted for BMI (a likely causal intermediate)

Conclusion:

EDIH scores, reflecting chronic hyperinsulinemia (i.e., greater insulin resistance with reduced clearance), were positively associated with the risk of incident gout, even beyond the pathway through adiposity. Conversely, higher DII scores, which reflect short-term, postprandial elevations in insulin levels (and also greater insulin clearance and sensitivity) conferred a lower risk. This corroborates human physiologic experiments and Mendelian Randomization studies showing insulin resistance can increase SU levels by decreasing renal excretion of urate, and supports lowering insulinemic potential of diet as a strategy to reduce gout risk.

References:

[1]Tabung et al. PMID 27821188

[2]Lee et al. PMID 32618519

[3]Wallace et al. PMID 856219

Disclosure of Interests:

Natalie McCormick: None declared, Chio Yokose: None declared, Leo Lu: None declared, Amit Joshi: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon

OP0202 DOES EXCESS WEIGHT AFFECT GOUT RISK DIFFERENTLY AMONG GENETICALLY PREDISPOSED INDIVIDUALS? – SEX-SPECIFIC PROSPECTIVE COHORT FINDINGS OVER >26 YEARS

Background:

Global burden of gout has increased substantially, particularly among women.1,2 Addressing obesity, a major modifiable risk factor for gout, may alleviate this burden; however, there is also a significant genetic contribution to gout risk according to the genome-wide association studies (GWAS).3,4 Genetic predisposition may modify the excess weight effect on gout risk.

Objectives:

To investigate the potential role of genetic predisposition on the association between excess weight (i.e., BMI ≥ 25 kg/m2) and gout risk in two US prospective longitudinal cohorts over >26 years, stratified by sex.

Methods:

We examined the association between excess weight and risk of incident gout meeting the ACR survey criteria,5 according to genetic risk, in 18,512 women from the Nurses’ Health Study (NHS) over 32 years, and 10,917 men from Health Professionals Follow-Up Study (HPFS) over 26 years. We derived a genetic risk score (GRS) using 114 serum urate single nucleotide polymorphisms from the latest GWAS.3 We also calculated the population attributable risk (PAR) for excess weight according to GRS stratum.

Results:

We ascertained 530 incident gout cases in NHS and 983 in HPFS. While the relative risks (RRs) due to excess weight (overweight or obesity) appeared larger among women above the mean than below the mean, the RRs among men appeared similar according to genetic predisposition (Table 1). The RRs among women for excess weight compared to normal were 1.66 (95% CI, 1.17 to 2.37) and 2.55 (1.95 to 3.34) below and above the mean GRS, respectively (P for multiplicative interaction = 0.06), whereas corresponding RRs among men were 1.68 (95% CI, 1.31 to 2.16) and 1.76 (1.47 to 2.10) (P for multiplicative interaction = 0.8). The risk differences (RD) among women for excess weight were 0.69 and 2.38 with GRS below and above the mean, respectively, resulting in the relative excess risk due to interaction (RERI) of 1.69 (95% CI, 1.03 to 2.35, P for additive interaction = 5.4x10-7); for men, the corresponding RDs were 0.70 and 1.46, with RERI = 0.76 (0.26, 1.25; P for additive interaction = 2.6x10-3). Excess weight accounted for a larger proportion of incident gout cases among women with GRS above the mean (PAR, 48.5% [95% CI, 38.8 to 55.9]) compared to those with GRS below the mean (PAR, 29.0% [95% CI, 10.5 to 42.1]), whereas the PARs among men were similar (31.6% vs 29.7%, respectively).

Table 1.

Relative Risk of Gout by Body Mass Index, Stratified by Mean Genetic Score

HPFS (men)Below MeanAbove MeanBMIOverall<2525-30>30Overall<2525-30>30No. Cases3338817273650172349129Person-Years10405543314492531148898634419944609610544Age-Adjusted RR-1.0 (ref)1.71 (1.32, 2.22)3.00 (2.18, 4.12)-1.0 (ref)1.80 (1.50, 2.16)2.87 (2.27, 3.62)MV Adjusted* RR-1.0 (ref)1.53 (1.18, 1.99)2.31 (1.66, 2.21)-1.0 (ref)1.63 (1.35, 1.96)2.38 (1.87, 3.03)NHS (women)Below MeanAbove MeanBMIOverall<2525-30>30Overall<2525-30>30No. Cases17347408635772120165Person-Years24439212384976414441292392591202297612342907Age-Adjusted RR-1.0 (ref)1.23 (0.81, 1.88)4.46 (3.10, 6.41)-1.0 (ref)2.41 (1.79, 3.23)5.68 (4.82, 7.52)MV Adjusted* RR-1.0 (ref)1.00 (0.65, 1.53)2.84 (1.92, 4.20)-1.0 (ref)1.97 (1.46, 2.65)3.61 (2.68, 4.87)

*Adjusted for age (continuous), menopause, use of hormone therapy (never, past or current), history of hypertension, and systolic and diastolic blood pressure, alcohol, total energy intake and intake of meat, seafood and dairy foods (all continuous).

Conclusion:

These large scale longitudinal prospective cohorts suggest maintaining healthy weight is an important gout prevention strategy, regardless of underlying genetic risk. In genetically predisposed individuals, addressing excess weight may prevent a large proportion of gout cases, especially among women.

References:

[1]Safiri et al., PMID 32755051

[2]Xia et al., PMID 31624843

[3]Tin et al., PMID 31578528

[4]Tai et al., PMID: 32017447

[5]Wallace et al., PMID: 856219

Acknowledgements:

The authors thank the participants of the NHS and HPFS.

CY is supported by the Rheumatology Research Foundation Scientist Development Award and NIH T32 AR007258. HC is supported by NIH P50AR060772 and R01AR065944.

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.

OP0235 PRO-INFLAMMATORY DIET AND RISK OF INCIDENT GOUT: 3 PROSPECTIVE COHORT STUDIES OF US MEN AND WOMEN

Background:

Emerging evidence suggests inflammation may drive progression from hyperuricemia to clinical gout, but the role of extrinsic, modifiable sources of chronic inflammation, such as diet, on gout risk is unknown. Notably, greater dietary inflammatory potential has been independently associated with increased risk of incident cardiovascular disease (CVD)1 and type 2 diabetes (T2D).2

Objectives:

Prospectively examine the relation between dietary inflammatory potential and risk of gout in three large cohorts of US women and men over 30 years.

Methods:

Ascertaining the ACR survey criteria for gout for several decades,3 we studied gout risk among 164,090 women from Nurses Health Study I (1986-2016) and II (1989-2017) and 40,598 men from Health Professionals Follow-up Study (1986-2016), free of gout at baseline. Dietary intake and covariates were assessed by validated questionnaires every 4 years. Inflammatory potential of diet was evaluated using a food-based empirical dietary index of inflammatory potential score (EDIP) pre-defined based on circulating levels of IL-6, C-reactive protein, adiponectin, and TNFαR2.4

We assigned an EDIP score for each participant, adjusted for total energy take, and prospectively examined the association between quintiles of EDIP score and incident gout, adjusting for potential confounders. We also stratified by alcohol intake, as alcohol has anti-inflammatory properties,4 but is associated with a higher gout risk, particularly beer.5

Results:

We documented 2,874 incident gout cases over 5,124,940 person-years of follow-up. In pooled multivariable-adjusted analyses, those in the highest EDIP quintile had 59% higher gout risk (multivariable RR 1.59; 95% CI 1.41–1.79), compared with the lowest (Table 1). This remained positive with further adjustment for BMI, a likely causal intermediate (RR 1.27, 1.12 to 1.42), and was stronger among non-drinkers (RR 2.37, 1.58 to 2.56) than drinkers (RR 1.57, 1.38 to 1.78) (Table 1).

Table 1.

Risk Ratio (95% CI) of Gout According to Quintiles of Inflammatory Diet Score, Overall and by Alcohol Use

Q1:lowestQ2Q3Q4Q5:highestP for trendOverallN cases473493530623755Person-years1,024,5711,025,6181,025,2841,024,7791,024,688Age-adjusted RR1.00 (Ref)1.05 (0.92, 1.19)1.13 (0.99, 1.27)1.33 (1.18, 1.50)1.64 (1.46, 1.84)<0.001MV-Adjusted* RR1.00 (Ref)1.04 (0.92, 1.18)1.12 (0.98, 1.26)1.31 (1.16, 1.48)1.59 (1.41, 1.79)<0.001MV-Adjusted** RR (+ BMI)1.00 (Ref)1.00 (0.88, 1.13)1.03 (0.91, 1.17)1.16 (1.02, 1.31)1.27 (1.12, 1.42)<0.001No Alcohol UseN cases265884143251Person-years118,301189,938249,389313,511396,080MV-Adjusted* RR1.00 (Ref)1.31 (0.82, 2.08)1.37 (0.88, 2.13)1.80 (1.18, 2.74)2.37 (1.58, 2.56)<0.001MV-Adjusted**RR (+ BMI)1.00 (Ref)1.28 (0.80, 2.03)1.32 (0.85, 2.05)1.61 (1.06, 2.45)1.85 (1.23, 2.79)<0.001Alcohol UseN cases447435446480504Person-years906,271835,680775,895711,267628,609MV-Adjusted* RR1.00 (Ref)1.04 (0.91, 1.19)1.13 (0.99, 1.29)1.31 (1.15, 1.50)1.57 (1.38, 1.78)<0.001MV-Adjusted** RR (+ BMI)1.00 (Ref)1.00 (0.88, 1.14)1.05 (0.92, 1.20)1.17 (1.03, 1.33)1.28 (1.12, 1.46)<0.001

*Multivariable (MV) models adjusted for age (month), White race, smoking, menopause (women only), hormone use (women only), physical activity, history of hypertension, and diuretic use. **MV + BMI models additionally adjusted for BMI (a likely causal intermediate)

Conclusion:

Habitual pro-inflammatory dietary pattern was independently associated with higher risk of incident gout in these prospective cohorts, even beyond the pathway through adiposity. Our findings support a role for chronic inflammation in development of gout, similar to CVD1 and T2D.2 Adhering to a diet with lower inflammatory potential may modulate systemic inflammation, potentially reducing gout risk and these life-threatening comorbidities.

References:

[1]Li et al. J Amer Coll Cardiology (2020) PMID 33153576

[2]Lee et al. Diabetes Care (2020) PMID 32873589

[3]Wallace et al. PMID 856219

[4]Tabung et al. PMID 27358416

[5]Choi et al. PMID 15094272

Disclosure of Interests:

Natalie McCormick: None declared, Chio Yokose: None declared, Leo Lu: None declared, Amit Joshi: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon

POS1428 VALIDATION OF ANCA-ASSOCIATED VASCULITIS AS THE CAUSE OF END-STAGE RENAL DISEASE IN THE UNITED STATES RENAL DATA SYSTEM

Background:

Glomerulonephritis and other renal manifestations are common in ANCA-associated vasculitis (AAV). Renal involvement in AAV is associated with adverse outcomes, including end-stage renal disease (ESRD) in up to 25% of patients (1). The United States Renal Data System (USRDS), a national registry of ESRD patients, represents a unique nationwide data source for studying AAV patients with ESRD. Prior research has assessed how often patients with ESRD attributed to AAV have biopsy-proven glomerulonephritis in USRDS (2), but the validity of the diagnosis of AAV as the cause of ESRD in the USRDS remains unknown.

Objectives:

We aim to validate the diagnosis of AAV as the primary cause of ESRD listed in USRDS.

Methods:

We identified all patients in the Mass General Brigham (MGB) healthcare system with a billing code for advanced chronic kidney disease or end-stage renal disease or procedure code for dialysis or renal transplantation. We identified all MGB patients fulfilling these criteria to records in the USRDS by name, sex, date of birth, and social security number. From this cohort of patients, we identified those with AAV or related diagnoses listed as the primary disease causing ESRD (ICD9: 446.0, 446.4 or ICD10: M31.3X, M31.7). Two authors reviewed medical records to collect information on whether or not a physician had diagnosed AAV, details of AAV history, renal and non-renal biopsies, and antineutrophil cytoplasmic antibody (ANCA) tests. Discrepancies were resolved through consensus. Details regarding initial ESRD onset date were obtained from the USRDS. To calculate the positive predictive value (PPV) for AAV as the primary cause of ESRD a definite physician diagnosis of AAV (a diagnosis confirmed by two physicians based on available data) in the MGB medical record was used as the gold standard. To calculate sensitivity, we linked the Partners (MGB) AAV Cohort to USRDS records using the same methods. A diagnosis code of AAV as the cause of ESRD was considered a true positive and a diagnosis code for other types of nephritis was considered a false negative.

Results:

We identified 89 USRDS records linked to MGB medical records in which the primary cause of ESRD was attributed to AAV. Of these, 85 were confirmed to be true cases of AAV after medical record review (PPV=96%) (Table 1). Among the cases classified as AAV, 84 (99%) had a positive ANCA test, which was predominantly MPO/P-ANCA (47, 55%); 36 (42%) had a renal biopsy, all of which were supportive of the diagnosis. The majority of cases were identified as AAV by ICD9 or 10 codes for Wegener’s granulomatosis (446.4 or M313.1). Within the Partners (MGB) AAV cohort linked to USRDS records, 33 (55%) of 60 identified cases had AAV listed as the cause of ESRD; in the remainder, ESRD was attributed to non-specific nephritis codes.

Table 1.

AAV and non-AAV patients in the USRDS with ESRD due to AAV (N=89)

Physician-Diagnosed AAV(N=85)ANCA type n (%)84 (98.8)MPO/P-ANCA+47 (55.3)PR3/C-ANCA+33 (38.8)Renal biopsy n (%)36 (42.4)Pauci-Immune Glomerulonephritis n (%)16 (44%)Non-renal biopsy n (%) Yes10 (11.8) No74 (87.1)Years from AAV diagnosis to ESRD median [IQR]1 [0, 6]Principal diagnosis code (ICD9/ICD10) n (%) Wegener’s granulomatosis (446.4, 446.4B, or M313.1)81 (95.3)

Conclusion:

We found that the diagnosis of AAV as the primary cause of ESRD in the USRD had a high PPV, suggesting accurate classification of ESRD due to AAV in the USRDS, but that sensitivity was moderate. These findings support the past and future use of the USRDS for research with ESRD attributed to AAV.

References:

[1]Moiseev S, Novikov P, Jayne D, Mukhin N. End-stage renal disease in ANCA-associated vasculitis. Nephrol Dial Transplant. 2017;32(2):248-53.

[2]Layton JB, Hogan SL, Jennette CE, Kenderes B, Krisher J, Jennette JC, et al. Discrepancy between Medical Evidence Form 2728 and renal biopsy for glomerular diseases. Clin J Am Soc Nephrol. 2010;5(11):2046-52.

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.

OP0203 GENE-DIET INTERACTION ON THE RISK OF INCIDENT GOUT AMONG WOMEN – PROSPECTIVE COHORT STUDY OVER 32 YEARS

Background:

Although gout is conventionally known as a male condition, the recent Global Burden of Disease (GBD) Study found disproportionate worsening among women.1 We have found Dietary Approaches to Stop Hypertension (DASH) diet is independently associated with a lower risk of incident gout, while Western diet is associated with increased risk.2 Whether these risks vary according to genetic risk remains unknown.

Objectives:

To investigate the influence of genetic predisposition on the relation between diets (one protective and another hazardous) and gout risk in a large prospective US cohort of women over 32 years.

Methods:

We examined the role of genes on the association between two dietary patterns (DASH and Western) on the risk of incident gout in 18,512 women from the Nurses’ Health Study. Using validated food frequency questionnaires, for each participant we derived: 1) DASH score emphasizing fruits, vegetables, nuts, legumes, whole grains, low-fat dairy, and reduced intake of saturated fat and sugar-sweetened beverages (SSBs) and 2) Western diet score characterized by high intake of red and processed meats, SSBs, desserts, French fries, and refined grains. A genetic risk score (GRS) was derived using 114 serum urate single nucleotide polymorphisms from the latest GWAS consortium.3

Results:

There were 523 incident gout cases meeting ACR survey criteria4 (170 vs. 353 in GRS below and above the mean, respectively) (Table 1). Among women with GRS below and above the mean, the multivariable relative risks (RRs) of gout were 1.0, 1.56. 1.32, 0.89, and 0.61 (0.34 to 1.09) and 1.0, 1.0, 0.85, 0.51, and 0.68 (0.49 to 0.96), for quintiles (Q) 1 through 5 of DASH score, respectively (p for interaction = 0.69) (Table 1). For the Western diet, RRs for Q1 through 5 were 1, 1.34, 1.07, 1.33, and 1.63 (0.91 to 2.93) for those with GRS below the mean and 1.0, 1.17, 0.93, 1.27, and 1.77 (1.19 to 2.61) among those with GRS above the mean, respectively (p for multiplicative interaction = 0.64).

Table 1.

Relative Risk of Gout by Quintiles of DASH and Western Diet Score, Stratified by Mean GRS

DASHBelow MeanAbove MeanQ1Q2Q3Q4Q5Q1Q2Q3Q4Q5P InteractionNo. Cases27495121227589903465Person-Years39208472475722734953587643981545853554013473356521Age-Adjusted RR1.0 (ref)1.43 (0.89, 2.29)1.22 (0.76, 1.96)0.8 (0.45, 1.42)0.5 (0.28, 0.88)1.0 (ref)0.97 (0.72, 1.33)0.79 (0.58, 1.07)0.47 (0.31, 0.70)0.54 (0.39, 0.76)0.73MV-Adjusted* RR1.0 (ref)1.56 (0.97, 2.51)1.32 (0.82, 2.12)0.89 (0.50, 1.59)0.61 (0.34, 1.09)1.0 (ref)1.0 (0.73, 1.37)0.85 (0.63, 1.17)0.51 (0.33, 0.76)0.68 (0.49, 0.96)0.69WesternBelow MeanAbove MeanQ1Q2Q3Q4Q5Q1Q2Q3Q4Q5P InteractionNo. Cases21362839465270567699Person-Years47397493484783747589452834552947913473574644785Age-Adjusted RR1.0 (ref)1.49 (0.86, 2.56)1.26 (0.71, 2.23)1.71 (1.00, 2.93)2.22 (1.31, 3.74)1.0 (ref)1.21 (0.85, 1.74)0.98 (0.67, 1.43)1.35 (0.94, 1.93)1.88 (1.34, 2.65)0.72MV-Adjusted* RR1.0 (ref)1.34 (0.78, 2.32)1.07 (0.60, 1.90)1.33 (0.76, 2.34)1.63 (0.91, 2.93)1.0 (ref)1.17 (0.81, 1.68)0.93 (0.63, 1.38)1.27 (0.87, 1.84)1.77 (1.19, 2.61)0.64

*Adjusted for age (continuous), menopause, use of hormone therapy (never, past or current), history of hypertension, systolic and diastolic blood pressure (continuous), alcohol (continuous), total energy intake (continuous), and intake of meat, seafood, and dairy foods (continuous).

Conclusion:

In this prospective female cohort that ascertained gout with standardized criteria over 32 years, regardless of genetic predisposition, DASH diet was similarly associated with lower risk of incident gout while Western diet was associated with a higher risk. The anticipated absolute impact of diet among genetically predisposed females was larger with greater absolute risk difference. These data agree with the recent GBD Study’s recommendation for intensive dietary and anti-obesity measures for gout prevention, especially in females.1

References:

[1]Xia et al., PMID 31624843

[2]Keller et al., PMID: 28487277

[3]Tin et al., PMID 31578528

[4]Wallace et al., PMID: 856219

Acknowledgements:

The authors thank the participants of the NHS.

CY is supported by the Rheumatology Research Foundation Scientist Development Award and NIH T32 AR007258. HC is supported by NIH P50AR060772 and R01AR065944.

Disclosure of Interests:

None declared

POS1124 IDENTIFYING POTENTIAL CLASSIFICATION CRITERIA FOR CALCIUM PYROPHOSPHATE DEPOSITION DISEASE (CPPD): RESULTS FROM THE INITIAL PHASES

Background:

Classification criteria for calcium pyrophosphate deposition disease (CPPD) will facilitate clinical research on this common crystalline arthritis. ACR/EULAR are jointly sponsoring development of CPPD classification criteria using a multi-phase process.

Objectives:

To report preliminary results from the first two phases of a four-phase process for developing CPPD classification criteria.

Methods:

CPPD classification criteria development is overseen by a 12-member Steering Committee. Item generation (Phase I) included a scoping literature review of five literature databases and contributions from a 35-member Combined Expert Committee and two Patient Research Partners. Item reduction and refinement (Phase II) involved a Combined Expert Committee meeting, discussions among Clinical, Imaging, and Laboratory Advisory Groups, and an item rating exercise to assess the influence of individual items toward classification. The Steering Committee reviewed the modal rating score for each item (range -3 [strongly pushes away from CPPD] to +3 [strongly pushes toward CPPD]) to determine items to retain for future phases of criteria development.

Results:

Item generation yielded 420 items (312 from the literature, 108 from experts/patients). The Advisory Groups eliminated items they agreed were unlikely to distinguish between CPPD and other forms of arthritis, yielding 127 items for the item rating exercise. Fifty-six items, most of which had a modal rating of +/- 2 or 3, were retained for future phases (see Table 1). As numerous imaging items were rated +3, the Steering Committee recommended focusing on imaging of the knee, wrist, and one additional affected joint for calcification suggestive of CPP crystal deposition.

Conclusion:

The ACR/EULAR CPPD classification criteria working group has adopted both data- and expert-driven approaches, leading to 56 candidate items broadly categorized as clinical, imaging, and laboratory features. Remaining steps for criteria development include domain establishment, item weighting through a multi-criteria decision analysis exercise, threshold score determination, and criteria validation.

Table 1.

Categories of items retained for future phases of classification criteria development

Age in decade at symptom onsetAcute inflammatory arthritis (e.g. knee, wrist, 1st MTP joint*)Recurrence and pattern of joint involvement (e.g. 1 self-limited episode, >1 self-limited episode)Physical findings (e.g. palpable subcutaneous tophus*, psoriasis*)Co-morbidities and family history (e.g. Gitelman disease, hemochromatosis, familial CPPD)Osteoarthritis location and features (e.g. 2nd or 3rd MCP joint, wrist)Synovial fluid findings (e.g. CPP crystals present, CPP crystals absent on 1 occasion* or 2 occasions*, monosodium urate crystals present*)Laboratory findings (e.g. hypomagnesemia, hyperparathyroidism, rheumatoid factor*, anti-CCP*)Plain radiograph: calcification in regions of fibro- or hyaline cartilage+Plain radiograph: calcification of the synovial membrane/capsule/tendon+Conventional CT: calcification in regions of fibro- or hyaline cartilage+Conventional CT: calcification of the synovial membrane/capsule/tendon+Ultrasound: CPP crystal deposition in fibro- or hyaline cartilage+Ultrasound: CPP crystal deposition in synovial membrane/capsule/tendons+Dual-energy CT: CPP crystal deposition in fibro- or hyaline cartilage+Dual-energy CT: CPP crystal deposition in synovial membrane/capsule/tendon+

*Potential negative predictor +Assessed in the knee, wrist, and/or 1 additional affected joint

Disclosure of Interests:

Sara Tedeschi Consultant of: NGM Biopharmaceuticals, Tristan Pascart: None declared, Augustin Latourte Consultant of: Novartis, Cattleya Godsave: None declared, Burak Kundaki: None declared, Raymond Naden: None declared, William Taylor: None declared, Nicola Dalbeth Speakers bureau: Abbvie and Janssen, Consultant of: AstraZeneca, Dyve, Selecta, Horizon, Arthrosi, and Cello Health, Tuhina Neogi: None declared, Fernando Perez-Ruiz: None declared, Ann Rosenthal: None declared, Fabio Becce Consultant of: Horizon Therapeutics, Grant/research support from: Siemens Healthineers, Eliseo Pascual: None declared, Mariano Andrés: None declared, Thomas Bardin: None declared, Michael Doherty: None declared, Hang Korng Ea: None declared, Georgios Filippou: None declared, John FitzGerald: None declared, Marwin Gutierrez: None declared, Annamaria Iagnocco: None declared, Tim Jansen Speakers bureau: Abbvie, Amgen, BMS, Grunenthal, Olatec, Sanofi Genzyme, Consultant of: Abbvie, Amgen, BMS, Grunenthal, Olatec, Sanofi Genzyme, Minna Kohler Speakers bureau: Lilly, Consultant of: Novartis, Frederic Lioté: None declared, Mark Matza: None declared, Geraldine McCarthy Consultant of: PK Med, Roberta Ramonda: None declared, Anthony Reginato: None declared, Pascal Richette: None declared, Jasvinder Singh Speakers bureau: Simply Speaking, Consultant of: Crealta/Horizon, Medisys, Fidia, UBM LLC, Trio health, Medscape, WebMD, Adept Field Solutions, Clinical Care options, Clearview healthcare partners, Putnam associates, Focus forward, Navigant consulting, Spherix, Practice Point communications, Francisca Sivera: None declared, Alexander So: None declared, Lisa Stamp: None declared, Janeth Yinh: None declared, Chio Yokose: None declared, Robert Terkeltaub Consultant of: Sobi, Horizon Therapeutics, Astra-Zeneca, Selecta, Grant/research support from: Astra-Zeneca, Hyon Choi: None declared, Abhishek Abhishek Consultant of: NGM Biopharmaceuticals.