The gout epidemic in French Polynesia: a modelling study of data from the Ma'i u'u epidemiological survey

BACKGROUND

Gout is the most common cause of inflammatory arthritis worldwide, particularly in Pacific regions. We aimed to establish the prevalence of gout and hyperuricaemia in French Polynesia, their associations with dietary habits, their comorbidities, the prevalence of the HLA-B*58:01 allele, and current management of the disease.

METHODS

The Ma'i u'u survey was epidemiological, prospective, cross-sectional, and gout-focused and included a random sample of adults from the general adult population of French Polynesia. It was conducted and data were collected between April 13 and Aug 16, 2021. Participants were randomly selected to represent the general adult population of French Polynesia on the basis of housing data collected during the 2017 territorial census. Each selected household was visited by a research nurse from the Ma'i u'u survey who collected data via guided, 1-h interviews with participants. In each household, the participant was the individual older than 18 years with the closest upcoming birthday. To estimate the frequency of HLA-B*58:01, we estimated HLA-B haplotypes on individuals who had whole-genome sequencing to approximately 5× average coverage (mid-pass sequencing). A subset of individuals who self-reported Polynesian ancestry and not European, Chinese, or other ancestry were used to estimate Polynesian-ancestry specific allele frequencies. Bivariate associations were reported for weighted participants; effect sizes were estimated through the odds ratio (OR) of the association calculated on the basis of a logistic model fitted with weighted observations.

FINDINGS

Among the random sample of 2000 households, 896 participants were included, 140 individuals declined, and 964 households could not be contacted. 22 participants could not be weighted due to missing data, so the final weighted analysis included 874 participants (449 [51·4%] were female and 425 [48·6%] were male) representing the 196 630 adults living in French Polynesia. The estimated prevalence of gout was 14·5% (95% CI 9·9-19·2), representing 28 561 French Polynesian adults, that is 25·5% (18·2-32·8) of male individuals and 3·5% (1·0-6·0) of female individuals. The prevalence of hyperuricaemia was estimated at 71·6% (66·7-76·6), representing 128 687 French Polynesian adults. In multivariable analysis, age (OR 1·5, 95% CI 1·2-1·8 per year), male sex (10·3, 1·8-60·7), serum urate (1·6, 1·3-2·0 per 1 mg/dL), uraturia (0·8, 0·8-0·8 per 100 mg/L), type 2 diabetes (2·1, 1·4-3·1), BMI more than 30 kg/m2 (1·1, 1·0-1·2 per unit), and percentage of visceral fat (1·7, 1·1-2·7 per 1% increase) were associated with gout. There were seven heterozygous HLA-B*58:01 carriers in the full cohort of 833 individuals (seven [0·4%] of 1666 total alleles) and two heterozygous carriers in a subset of 696 individuals of Polynesian ancestry (two [0·1%]).

INTERPRETATION

French Polynesia has an estimated high prevalence of gout and hyperuricaemia, with gout affecting almost 15% of adults. Territorial measures that focus on increasing access to effective urate-lowering therapies are warranted to control this major public health problem.

FUNDING

Variant Bio, the French Polynesian Health Administration, Lille Catholic University Hospitals, French Society of Rheumatology, and Novartis.

Cardiovascular Safety of Febuxostat in Patients With Gout or Hyperuricemia: A Systematic Review of Randomized Controlled Trials

INTRODUCTION

To this date, a causal relationship between febuxostat and cardiovascular disease remains controversial as comparison between trials can be challenging and may lead to misleading conclusions, especially when facing heterogeneous cardiovascular outcomes. We aimed to compare the cardiovascular outcomes in the most pertinent trials of febuxostat compared with controls.

METHODS

We searched electronic databases using a PICOS-style approach search strategy of randomized controlled trials (RCTs) on cardiovascular outcomes of febuxostat in patients with gout or hyperuricemia. We conducted a quality and risk of bias assessment of the included clinical trials. The definition of major adverse cardiovascular event as well as all reported cardiovascular outcomes were retrieved from every involved trial.

RESULTS

Of the 1173 records identified from all sources, 20 RCTs were included in the analysis. The mean duration of follow-up was 69.7 ± 81.5 weeks, and febuxostat dose ranged from 10 to 240 mg with 80 mg being the most commonly used dosage. Overall, the quality of evidence deriving from all RCTs showed concerns in most studies (65%). Major adverse cardiovascular event was defined in 7 of the 20 RCTs (35%), and cardiovascular outcome reporting was very heterogeneous. Overall, the data of cardiovascular safety of febuxostat were reassuring.

CONCLUSIONS

Our systematic review showed high level of concerns in quality assessment domains as well heterogeneous cardiovascular outcomes across included studies. Cardiovascular outcomes in the majority of White males with gout treated with febuxostat were reassuring when compared with allopurinol. Further studies are needed to draw conclusions in patients with severe cardiovascular disease.

Systemic inflammatory cytokine profiles in patients with gout during flare, intercritical and treat-to-target phases: TNFSF14 as new biomarker

INTRODUCTION

Untreated gout is characterised by monosodium urate (MSU) crystal accumulation responsible for recurrent flares that are commonly separated by asymptomatic phases. Both phases are inflammatory conditions of variable intensity. Gout flares are self-limited inflammatory reactions involving multiple mediators. This study aimed to characterise the inflammatory profiles of gout at different phases.

METHODS

Using the Olink targeted proteomics, levels of 92 inflammation-related proteins were measured in plasma samples of a prospective gout population (GOUTROS), collected at gout flare (T1), the intercritical phase (T2) and after reaching the target serum urate level under urate-lowering therapy (T3). Results were validated in an independent cohort (OLT1177-05) with plasmas collected at T1 and T2. Ex vivo and in vitro experiments were performed to assess the inflammatory properties of new biomarkers.

RESULTS

In total, 21 inflammatory new biomarkers were differentially expressed during the three time-points of gout disease. The levels of four of these proteins (interleukin 6 (IL-6), colony-stimulating factor 1, vascular endothelial growth factor A and tumour necrosis factor superfamily 14 (TNFSF14)) were increased during gout flare in an independent cohort. IL-6 and TNFSF14 had the highest fold change in expression during T1 versus T2 or T3. TNFSF14 was produced at the inflamed joint and enhanced the inflammatory response induced by lipopolysaccharide and MSU crystal stimulation. Conversely, TNFSF14 blockade reduced the inflammatory response. Additionally, single nucleotide polymorphisms of TNFSF14 affected the ability of myeloid cells to produce inflammatory cytokines.

CONCLUSION

Gout flare involves multiple inflammatory mediators that may be used as potential therapeutic targets.

Early-onset gout and rare deficient variants of the lactate dehydrogenase D gene

OBJECTIVES

To investigate whether the lactate dehydrogenase D (LDHD) gene deficiency causes juvenile-onset gout.

METHODS

We used whole-exome sequencing for two families and a targeted gene-sequencing panel for an isolated patient. d-lactate dosages were analysed using ELISA.

RESULTS

We demonstrated linkage of juvenile-onset gout to homozygous carriage of three rare distinct LDHD variants in three different ethnicities. In a Melanesian family, the variant was (NM_153486.3: c.206C>T; rs1035398551) and, as compared with non-homozygotes, homozygotes had higher hyperuricaemia (P = 0.02), lower fractional clearance of urate (P = 0.002), and higher levels of d-lactate in blood (P = 0.04) and urine (P = 0.06). In a second, Vietnamese, family, very severe juvenile-onset gout was linked to homozygote carriage of an undescribed LDHD variant (NM_153486.3: c.1363dupG) leading to a frameshift followed by a stop codon, p.(AlaGly432fsTer58). Finally, a Moroccan man, with early-onset and high d-lactaturia, whose family was unavailable for testing, was homozygous for another rare LDHD variant [NM_153486.3: c.752C>T, p.(Thr251Met)].

CONCLUSION

Rare, damaging LDHD variants can cause autosomal recessive early-onset gout, the diagnosis of which can be suspected by measuring high d-lactate levels in the blood and/or urine.

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.

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.

Evaluating the safety and short-term equivalence of colchicine versus prednisone in older patients with acute calcium pyrophosphate crystal arthritis (COLCHICORT): an open-label, multicentre, randomised trial

BACKGROUND

Acute calcium pyrophosphate crystal arthritis causes intense joint pain mainly affecting older people. Because guidance and evidence remain scarce, management of this disease relies on expert opinion. We therefore aimed to compare the safety and short-term equivalence of low-dose colchicine with oral prednisone in older patients with acute calcium pyrophosphate crystal arthritis.

METHODS

We did an open-label, multicentre, randomised, trial (COLCHICORT) at six hospitals in Paris and northern France. We enrolled patients who were admitted to hospital who were 65 years or older and who presented with acute calcium pyrophosphate crystal arthritis with a symptom duration of less than 36 h. Diagnosis of calcium pyrophosphate crystal arthritis was made by the identification of calcium pyrophosphate crystals on synovial fluid analysis or typical clinical presentation (onset of joint pain and swelling). Key exclusion criteria included absence of calcium pyrophosphate crystals on synovial fluid analysis or a history of gout. Participants were randomly allocated (1:1), using a centralised electronic treatment group allocation module, to receive either colchicine 1·5 mg on day 1 and 1 mg on day 2 (ie, the colchicine group) or oral prednisone 30 mg on days 1 and 2 (ie, the prednisone group). The primary outcome was change in joint pain (measured by visual analogue scale [VAS] from 0 mm to 100 mm) at 24 h. Equivalence was determined whether the 95% CI of the between-group difference at 24 h was within the -13 mm to +13 mm margin in the per-protocol analysis. Adverse events were recorded using the National Cancer Institute Common Terminology Criteria for Adverse Events (version 4.0). This trial is completed and is registered with ClinicalTrials.gov, NCT03128905.

FINDINGS

Between Feb 5, 2018, and May 7, 2022, 111 patients who were admitted to hospital were randomly assigned (57 [51%] to the colchicine group and 54 [49%] to the prednisone group). 95 (86%) of 111 patients were included in the per-protocol analysis (49 [52%] in the colchicine group and 46 [48%] in the prednisone group). The median age was 88·0 years (IQR 82·0-91·0) and 69 (73%) of 95 participants were women and 26 (27%) were men. Acute calcium pyrophosphate crystal arthritis affected mainly the knee in 46 (48%) of 95 participants, the wrist in 19 (20%), and the ankle in 12 (13%). Pain VAS at baseline was 68 mm (SD 17). At 24 h, change in pain VAS was -36 mm (SD 32) in the colchicine group and -38 mm (SD 23) in the prednisone group. The between-group difference in change in pain VAS at 24 h was -1 mm (95% CI -12 to 10), showing equivalence between the two drugs. In the colchicine group, 12 (22%) of 55 patients had diarrhoea, one (2%) had hypertension, and none had hyperglycaemia. In the prednisone group, three (6%) of 54 had diarrhoea, six (11%) had hypertension, and three (6%) had hyperglycaemia. No deaths occurred in the colchicine group; two deaths occurred in the prednisone group, which were deemed unrelated to prednisone (one due to infectious valvular endocarditis leading to heart failure, and one due to a stroke).

INTERPRETATION

Colchicine and prednisone exhibit equivalent short-term efficacy for the treatment of acute calcium pyrophosphate crystal arthritis, with different safety profiles in the older population.

FUNDING

French Inter-regional Hospital Program of Clinical Research.

Identifying Potential Classification Criteria for Calcium Pyrophosphate Deposition Disease: Item Generation and Item Reduction

OBJECTIVE

Classification criteria for calcium pyrophosphate deposition (CPPD) disease will facilitate clinical research on this common crystalline arthritis. Our objective was to report on the first 2 phases of a 4-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 5 literature databases and contributions from a 35-member combined expert committee and 2 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 that 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. As numerous imaging items were rated +3, the steering committee recommended focusing on imaging of the knee and wrist and 1 additional affected joint for calcification suggestive of CPP crystal deposition.

CONCLUSION

A data- and expert-driven process is underway to develop CPPD classification criteria. Candidate items comprise clinical, imaging, and laboratory features.

POS1189 RHEUMATIC FEVER AND CUTANEOUS STREPTOCOCCAL INFECTION: A CASE-CONTROL STUDY IN THE LOYALTY ISLANDS, NEW CALEDONIA

Background

Acute Rheumatic Fever (ARF) and Rheumatic Heart Disease (RHD) remain major public health problems in the South Pacific. Triggering by group A beta hemolytic streptococcal (GAS) skin infection has been suspected but little documented1. Very high incidences of ARF (106/100 000) and cutaneous infections have been reported in the Loyalty islands (New Caledonia), where health care of the 20,000 Melanesian inhabitants is centralized in a few locations and provides an extensive electronic database since 1998, and systematic screening for RHD is regularly performed.

Objectives

To explore the link between ARF, RHD and skin infections by a retrospective case-control study.

Methods

The study was approved by the New Caledonian committee of Ethics and dealt with patients aged 6 to 26 years, seen from 1998 to 2018. Cases were ARF and/or RHD. Definite ARF was diagnosed according to the Jones criteria2; additional cases with strong clinical suspicion were also included as probable cases. RHD was diagnosed by cardiac ultrasound scan allowing definite and borderline diagnosis2. Sore throat and presumed streptococcal cutaneous infections were diagnosed by an algorithm, previously validated on a sample of 3000 events by an experimented clinician, which identified specific medical terms and ICD-10 codes in the electronic medical records. Each case was matched with 3 controls (without ARF and RHD) of same age, sex and living location. Infections were retrieved from the electronic medical records during the month, 6 months, one year, 5 years preceding the date of the first ARF/RHD diagnosis, for each case with the same index date for its matched control, and since birth. Numbers of infections per these time intervals were compared between cases and controls by univariate and multivariate conditional regression analysis in the total study population and its various subcategories (definite or probable ARF, definite or borderline RHD).

Results

311 cases of ARF and RHD including 206 definite cases were identified. Polyarthralgias (48%) were the main clinical presentation. Marginal erythema was not seen and Sydenham chorea was rare (6.8%). Mean age of diagnosis was 10.6 ±3.8 years. Skin infection episodes were 3 to 4 times more frequent than sore throats in all studied time-intervals.

Multivariate analysis showed an increased exposure to skin infections and sore throats in the year preceding ARF/RHD diagnosis in the whole population of cases as compared to controls (OR 2.18, 95% CI 1.46, 3.26) and 1.54, 95% CI 1.01, 2.36] respectively); skin infections (but not sore throat) were also increased the 206 definite cases (OR 1.34, 95% CI 1.01, 1.80) and in the 220 definite and probable ARF (OR 1.47, 95% CI 1.11, 1.94). In addition we observed a correlation between the seasonality of ARF and skin infections, which were both more frequent during the rainy season, and an overlap of areas with high incidence of ARF and areas with high incidence of skin infections.

Conclusion

Our results support the hypothesis that GAS skin infections play a role in the pathophysiology of ARF/RHD. In view of these results, there is an urgent need to implement preventive measures to reduce the incidence of skin infections in the Loyalty Islands.

References

[1]Oliver J, Bennett J, Thomas S, et al. Preceding group A streptococcus skin and throat infections are individually associated with acute rheumatic fever: evidence from New Zealand. BMJ Global Health 2021;6:e007038.

[2]Gewitz MH, Baltimore RS, Tani LY et al. American Heart Association Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease of the Council on Cardiovascular Disease in the Young. Revision of the Jones Criteria for the diagnosis of acute rheumatic fever in the era of Doppler echocardiography: a scientific statement from the American Heart Association. Circulation. 2015 May 19;131(20):1806-18.

Acknowledgements

We would like to thank, Marie-Rose Waia, Emile Gaze, Julien Rannou from Direction de l’Action Communautaire et de l’Action Sociale, Dr Jean-Michel Meunier and Nina Guillot from Agence Sanitaire et Sociale of New Caledonia

Disclosure of Interests

None declared

POS1169 THE INFLAMMATION INDUCED BY MONOSODIUM URATE AND CALCIUM PYROPHOSPHATE CRYSTALS DEPENDS ON OSMOLARITY AND AQUAPORIN CHANNELS

Background

The inflammation induced by monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals is driven by interleukin (IL)-1β production. This later relies on NLRP3 inflammasome which can be activated by variation of ion concentration.

Objectives

To assess the role of osmolarity and water flux in MSU and CPP crystal-induced inflammation.

Methods

In vitro, THP1 monocytes were stimulated by pyrogen-free synthetic MSU and CPP crystals in iso-, hypo- or hyperosmotic media. Cytokine production was quantified by ELISA in cell culture supernatants. Cell size was measured using video microscopy. The role of aquaporin channels was assessed by pharmacological inhibitor (mercury chloride, HgCl2). In vivo, murine air pouch model was used. MSU and CPP crystals were injected in air pouch of mice treated or not with HgCl2 or mannitol. Osmolarity of mouse sera and patient synovial fluids (SF) were measured using freezing point osmometer. The size of cells collected from SF was assessed with imageJ software.

Results

MSU and CPP crystal-induced IL-1β production was substantially reduced by HgCl2 treatment (MSU 4900 vs 880 pg/ml; CPP 10500 vs 980, p<0.0001) or when cells were cultured in hyperosmotic medium. MSU and CPP crystals induced a transient increase in cell size which was 1.6 and 1.5 bigger after 30 and 100 min of stimulation by MSU and CPP crystals, respectively. After 150 min of stimulation, cell size decreased to their baseline size. Cell size increase was abolished by HgCl2 or hyperosmotic medium. In vivo, MSU and CPP crystal-induced inflammation (assessed by cell infiltration, IL-1β and CXCL2 production in air pouch lavage) was drastically reduced by HgCl2 or mannitol treatment. The serum osmolarity was higher in mannitol-treated mice than untreated mice (320 vs 300 mmosm/L). In patients, cells collected from SF during CPP or MSU crystal-induced flares had a bigger size than cells collected from osteoarthitic SF. The osmolarity of MSU or CPP crystal-containing SF was lower than the osmolarity of osteoarthritic SF (270 vs 310 mmosm/L). Finally, the IL-1β concentration in SF was strongly correlated with cell size and SF osmolarity.

Conclusion

These results suggest that the variation of osmolarity plays central role in MSU and CPP crystal-induced inflammation. Deciphering how crystals modulate osmolarity will identify new therapeutic targets.

Disclosure of Interests

None declared

POS1161 CAN DOCTORS TREAT GOUT WELL? INSIGHT ON GOUT MANAGEMENT IN REFERRAL CENTRES

Background

Recent studies have shown a lack of implementation of gout recommendations in primary care. In this context of therapeutic inertia, the French Society of Rheumatology (SFR) published its first recommendations on gout (RECO) in 2020 [1,2], which were deliberately simple and concise.

Objectives

To determine the profile of patients referred to French gout expert centres, and to examine the results of their management.

Methods

Three hundred patients attending a first visit for gout management in three French referral centres were retrospectively included. Visits were performed at baseline (M0) and scheduled for month 6 (M6), month 12 (M12), and month 24 (M24). Data collected included: patient profile; disease activity and treatments; serum urate (SU) level; estimated glomerular filtration rate (eGFR).

Results

Patients were 81% male, mean age 62.2 ± 15.2 years, 42.7% prevalence of eGFR <60ml/min/1.73m2, 28.1% diabetes mellitus, and 25.4% had a history of major cardiovascular event. Management followed French recommendations after the baseline visit in 94.9% of cases. Overall, 50 patients (16.7%) received off-label anakinra for flare treatment or flare prophylaxis. SU levels were below 6.0mg/dL in 59.4% of patients at M6, 67.9% at M12, and 78.6% at M24. At M24, 50% of patients were treated with allopurinol (313 ± 105 mg/d), which exceeded renal restrictions of doses in 61.5% of them, and 48.2% received febuxostat (84 ± 36mg/d). At inclusion, 94% of patients had experienced at least one flare in the previous six months, versus 23.6% at M12, and 13.1% at M24 (of which 8/12 (66.7%) had SU>6.0mg/dL).

Conclusion

Simple application of gout management guidelines is feasible in clinical practice, and is efficient with a majority of patients achieving SU targets and clinical improvement. A minority of patients in referral centres have ‘difficult-to-treat’ gout requiring specific management.

References

[1]Latourte A, et al. 2020 Recommendations from the French Society of Rheumatology for the management of gout: Management of acute flares. Joint Bone Spine 2020;87:387-93.

[2]Pascart T, et al. 2020 recommendations from the French Society of Rheumatology for the management of gout: Urate-lowering therapy. Joint Bone Spine 2020;87:395- 404.

Disclosure of Interests

Charlotte Jauffret: None declared, Sebastien Ottaviani: None declared, Augustin Latourte Consultant of: Novartis, Hang Korng Ea: None declared, Sahara Graf: None declared, Frederic Lioté Grant/research support from: for the European Crystal Network workshops from Astra-Zeneca, Grunenthal, Horizon Pharmaceuticals, Ipsen Pharma, Menarini France and global, Novartis France, Olatec, Selecta, SOBI, Thomas Bardin Consultant of: Astra-Zeneca, Biomex, Grunenthal, Horizon Pharmaceuticals, Ipsen Pharma, Menarini France and global, Novartis France, Savient and Sobi, Pascal Richette: None declared, Tristan Pascart Consultant of: from Novartis, Grant/research support from: from Horizon Pharmaceuticals, Novartis, Variant Bio

POS1165 ASSOCIATION OF LDHD RARE VARIANTS WITH EARLY-ONSET GOUT IN TWO FAMILIES WITH AN ADDITIONAL ASSOCIATION OF RHBG VARIANT IN ONE

Background

Elevated lactate is known to favor urine urate reabsorption by the URAT1 urate/anion exchanger. Autosomal recessive gout caused by pathogenic variant in the LDHD gene encoding for D-lactate deshydrogenase has been recently identified in a large consanguineous Bedouin-Israeli kindred (1).

Objectives

We report here on two families in whom early-onset gout was linked to other variants leading to deficient D-LDH enzymes.

Methods

Studies of the two families were approved by appropriate Ethics committees. Whole exome sequencing (WES) was used to identify the genetic cause of familial gout. Dosages of D-lactate were performed on immediately frozen serum and urine samples by ELISA, using a D-lactate colorimetric assay kit (Abcam ab83429).

Results

Family 1 was Melanesian, living in the Lifou island of New Caledonia. The two index patients were two sisters who developed gout at the age of 13 and 16 years respectively. When seen at the ages of 25 and 27 years, they both had severe gout with frequent polyarticular flares, and multiple tophi and destructive arthropathies in the earliest age of onset one. WES, performed on the 2 affected sisters, their non-consanguine parents, and an unaffected brother, showed that the 2 affected sisters carried homozygous rare variant in DLDH gene (NM_153486.3: c.206 C>T; rs1035398551). This variant was at heterozygote level in both parents and absent in the unaffected brother. It was considered as probably damaging according to in silico prediction software. No association with any other gene was found.

The c.206C>T variant in LDHD was searched by Sanger sequencing method in 13 other extended family members. One 23 year-old brother of the two diseased sisters with atypical MTP flares, high uricemia and double contours at US examination of his MTPs, carried the c.206 C>T variant at the homozygous level. Three other heterozygous patients were found; two of whom were male with late-onset gout, the third one being a non-menopausal female with no gout. No variant carrier was found in the other 9 genotyped family members. The 3 homozygous patients for the c.206 C>T variant had very high hyperuricemia (range 738-834 was searched by Sanger sequencing method in 13 other extended family members. One 23 year-old brother of the two diseased sisters with atypical MTP flares, high uricemia and double contours at US examination of had very low or no D-lactate in plasma and urine. L-lactate blood and urine levels were normal in all subjects.

Family 2 was Vietnamese, living in a remote area of central Vietnam. The two affected children suffered from an extremely severe, destructive gout, which started at the age of 21 years in a daughter and at the age of 9 in her youngest brother, who had developed for the last 3 years, dysarthria, night shakes, memory loss, urine incontinence and an inability to read and count and died at the age of 34, a few months after being seen by us. WES was performed in the two probands, their father and mother (who denied consanguinity), and an unaffected brother. An undescribed variant in LDHD (NM_153486.3: c.1363dupG) was identified in homozygous level in the 2 juvenile gout patients and at the heterozygous level in their 2 parents and unaffected brother. This variant led to a frameshift followed by a stop codon p.(AlaGly432fsTer58). In addition, the two juvenile gout patients were homozygous for an undescribed frameshift (NR_046115.1: c.1064dup) variant of the RHBG gene encoding for a Rhesus Blood Group family ammonium transporter. The two parents carried the heterozygous variant which was not identified in the non-gout brother.

Conclusion

We report on 2 families in whom autosomal recessive juvenile gout was due to rare or undescribed, damaging LDHD gene variants. In addition, we observed in the Vietnamese family, an additional non-described frameshift homozygous variant in RHBG, the pathophysiological role of which deserves to be investigated.

References

[1]Drabkin M et al. Hyperuricemia and gout caused by missense mutation in D-lactate dehydrogenase. J Clin Invest. 2019;129:5163-5168

Disclosure of Interests

Thomas Bardin Consultant of: leo Pharma, Yves-Marie Ducrot: None declared, Quang Nguyen: None declared, Emmanuel Letavernier: None declared, Hang-Korng Ea: None declared, Frederic Touzain: None declared, Duc Minh Do: None declared, Julien Corot: None declared, Yan Barguil: None declared, Antoine Biron: None declared, Pascal Richette: None declared, Corinne Collet: None declared

Do Glucocorticoid Injections Increase the Risk of Knee Osteoarthritis Progression Over 5 Years?

OBJECTIVE

Recent findings have demonstrated that intraarticular (IA) glucocorticoid injections can be deleterious for knees with osteoarthritis (OA). This study was undertaken to assess, in a real-life setting, the risk of knee OA progression in patients who received IA glucocorticoid injections over a 5-year follow-up period.

METHODS

We used marginal structural modeling with inverse probability of treatment weighting to determine the causal association between IA glucocorticoid injections and the 5-year risk of disease progression in patients with symptomatic knee OA from the Knee and Hip Osteoarthritis Long-term Assessment cohort. OA progression was defined as an incident total knee replacement (TKR) and/or radiographic worsening (Kellgren/Lawrence [K/L] grade or joint space narrowing [JSN]). We also examined these outcomes in knees that received IA hyaluronan (IAHA) injections.

RESULTS

Among the 564 patients with knee OA included in the study sample, 51 (9.0%) and 99 (17.5%) received IA glucocorticoid or IAHA injections, respectively, and 414 (63.1%) did not receive any injection during follow-up. Compared to untreated knees, those treated with IA glucocorticoid injections had a similar risk of incident TKR (hazard ratio [HR] 0.92 [95% confidence interval (95% CI) 0.20, 4.14]; P = 0.91) or K/L grade worsening (HR 1.33 [95% CI 0.64, 2.79]; P = 0.44). IAHA injections had no effect on the risk of TKR (HR 0.81 [95% CI 0.14, 4.63]; P = 0.81) or K/L grade worsening (HR 1.36 [95% CI 0.85, 2.17]; P = 0.20). Similar results were obtained for JSN, and when TKR and radiographic outcomes were combined.

CONCLUSION

In this study, IA glucocorticoid injections for symptomatic knee OA did not significantly increase the 5-year risk of incident TKR or radiographic worsening. These findings should be interpreted cautiously and replicated in other cohorts.

Development of a radiographic scoring system for new bone formation in gout

Background

Features of new bone formation (NBF) are common in tophaceous gout. The aim of this project was to develop a plain radiographic scoring system for NBF in gout.

Methods

Informed by a literature review, scoring systems were tested in 80 individual 1st and 5th metatarsophalangeal joints. Plain radiography scores were compared with computed tomography (CT) measurements of the same joints. The best-performing scoring system was then tested in paired sets of hand and foot radiographs obtained over 2 years from an additional 25 patients. Inter-reader reproducibility was assessed using intraclass correlation coefficients (ICC). NBF scores were correlated with plain radiographic erosion scores (using the gout-modified Sharp-van der Heijde system).

Results

Following a series of structured reviews of plain radiographs and scoring exercises, a semi-quantitative scoring system for sclerosis and spur was developed. In the individual joint analysis, the inter-observer ICC (95% CI) was 0.84 (0.76–0.89) for sclerosis and 0.81 (0.72–0.87) for spur. Plain radiographic sclerosis and spur scores correlated with CT measurements (r = 0.65–0.74, P < 0.001 for all analyses). For the hand and foot radiograph sets, the inter-observer ICC (95% CI) was 0.94 (0.90–0.98) for sclerosis score and 0.76 (0.65–0.84) for spur score. Sclerosis and spur scores correlated highly with plain radiographic erosion scores (r = 0.87 and 0.71 respectively), but not with change in erosion scores over 2 years (r = −0.04–0.15).

Conclusion

A semi-quantitative plain radiographic scoring method for the assessment of NBF in gout is feasible, valid, and reproducible. This method may facilitate consistent measurement of NBF in gout.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-021-02683-9.

Distribution of bony erosions in feet and performance of two bone erosion scores: A dual-energy computed tomography study of 61 patients with gout

OBJECTIVES

To assess the distribution of bone erosions and two erosion scores in the feet of patients with gout and analyze the association between erosion scores and monosodium urate (MSU) crystal deposition using dual-energy computed tomography (DECT).

MATERIALS AND METHODS

We included all patients who underwent DECT of both feet between 2016 and 2019 in our radiology department, with positive detection of MSU deposits. Data on sex, age, treatment, serum urate, and DECT urate volumes were obtained. CT images were analyzed to score bone erosions in 31 sites per foot by using the semi-quantitative method based on the Rheumatoid Arthritis MRI Scoring (RAMRIS) system and the Dalbeth-simplified score. Reproducibility for the two scores was calculated with intraclass correlation coefficients (ICCs). Correlations between clinical features, erosion scores and urate crystal volume were analyzed by the Spearman correlation coefficient (r).

RESULTS

We studied 61 patients (mean age 62.0 years); 3,751 bones were scored. The first metatarsophalangeal joint and the midfoot were the most involved in terms of frequency and severity of bone erosions. The distribution of bone erosions was not asymmetrical. The intra- and inter-observer reproducibility was similar for the RAMRIS and Dalbeth-simplified scores (ICC 0.93 vs 0.94 and 0.96 vs 0.90). DECT urate volume was significantly correlated with each of the two erosion scores (r = 0.58-0.63, p < 0.001). There was a high correlation between the two scores (r = 0.96, p < 0.001).

CONCLUSIONS

DECT demonstrates that foot erosions are not asymmetric in distribution and predominate at the first ray and midfoot. The two erosion scores are significantly correlated with DECT urate volume. An almost perfect correlation between the RAMRIS and Dalbeth-simplified scores is observed.

Epidemiology of gout and hyperuricemia in New Caledonia

OBJECTIVES

New Caledonia is a Pacific island of 270,000 inhabitants with mixed ethnicities, including Polynesians (10.2%), people from European ancestry (27.2%), and Melanesians (39.1%),. This study aimed at determining the prevalence of gout and hyperuricemia in the general population and the various ethnicities of New Caledonia.

METHODS

A 3-degree random sample of the population aged 18 to 60 years was adjusted according to the 2014 New Caledonia census. Face-to-face planned interviews and physical measurements were performed by trained nurses. All consenting participants underwent capillary measurement of creatinine; all consenting men and only women older than 40 years underwent point-of-care uricemia testing. Gout was defined by a validated algorithm. Two definitions of hyperuricemia were used: capillary level equivalent to plasma uric acid level>360μmol/l (6mg/dl) and>420μmol/l (7mg/dl) and/or urate-lowering drug treatment for both thresholds.

RESULTS

We included 1144 participants (adjusted mean age 37.7±12.0 years; adjusted sex ratio 50.4% men). The adjusted prevalence of gout was 3.3% (95% confidence interval 2.2-4.9). Prevalence was 6.7% (2.5-16.8), 4.1% (1.8-8.9), and 2.6% (1.4-4.7) for Polynesians, Europeans and Melanesians, respectively, and 1.9% (0.5-6.6) for other ethnicities. Prevalence of hyperuricemia, determined in 658 participants, was 67.0% (61.9-71.6) and 37.0% (32.3-42.0) for the 360- and 420-μmol/l thresholds, respectively, and was significantly greater for Polynesians and Melanesians than Europeans for both thresholds.

CONCLUSIONS

The prevalence of gout and hyperuricemia in New Caledonia was high, including in patients of European descent.

Calcium Pyrophosphate Crystal Deposition in a Cohort of 57 Patients with Gitelman Syndrome

OBJECTIVE

Gitelman syndrome (GS) is the most frequent salt-wasting genetic tubulopathy and a source of hypokalaemia and hypomagnesemia. Chondrocalcinosis (CC) is a frequent feature of GS. The aim of our study was to determine the prevalence, distribution patterns, clinical phenotypes and risk factors of CC in GS.

METHODS

This prospective study of a cohort of 57 patients with GS included a systematic screening for CC by peripheral joint radiography, cervical spine computerized tomography (CT) and joint ultrasonography. The prevalence of cervical C1-C2 CC by CT was compared between 33 GS patients and sex- and age-matched controls. Clinical and biochemical features were analysed to identify factors associated with CC.

RESULTS

Mean age of patients was 46.5 ± 12.4 years, 66.7% were women, and 93.0% carried SLC12A3 mutations. Mean serum magnesium level was 0.60 ± 0.30 mmol/l. CC was observed in 79% of patients, with the highest prevalence at the cervical spine (81.8%) followed by the knee (52.6%), wrist (50.9%), ankle (38.6%), temporomandibular joint (36.4%), shoulder (33.3%), hip (22.8%), elbow (14.0%) and sclero-choroid (12.1%). Prevalence of CC at the C1-C2 level was higher in the GS cohort than control group (72.7% vs 9.1%) (adjusted odds ratio 21.0, 95% CI 2.8-156.1, p= 0.003). Independent factors associated with CC were low serum magnesium level and age.

CONCLUSION

GS was associated with widespread CC, favoured by aging and hypomagnesemia. The C1-C2 level was the most affected site. Follow-up of this unique cohort will help understanding the clinical consequences of CC, especially the precise characterization of pyrophosphate arthropathy.

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.

Calcium Pyrophosphate Dihydrate Crystal Deposition in Gouty Tophi

OBJECTIVE

The coexistence of calcium pyrophosphate dihydrate (CPPD) and monosodium urate monohydrate crystals in gouty tophi has rarely been reported. We undertook this study to investigate CPPD crystal deposits in a series of surgically removed gouty tophi and to identify factors associated with these deposits.

METHODS

Twenty-five tophi from 22 gout patients were analyzed using polarized light microscopy, field emission scanning electron microscopy (FESEM), and μ Fourier transform infrared (μFTIR) spectroscopy.

RESULTS

Tophi consisted of multiple lobules separated by fibrous septa and surrounded by a foreign-body giant cell reaction. CPPD crystal aggregates were identified in 9 of 25 tophi from 6 patients. CPPD crystals were dispersed or highly compacted, localized at the edge or inside the tophus lobules, with some lobules completely filled with crystals. Both monoclinic and triclinic CPPD crystal phases were identified using FESEM and μFTIR. Compared to patients without CPPD, those with CPPD-containing tophi were older (mean 60.5 years versus 47.2 years; P = 0.009), and had longer-term gout duration (mean 17.0 years versus mean 9.0 years; P < 0.05) and tophi duration (mean 10.0 years versus mean 4.6 years; P < 0.01). None of the patients had radiographic chondrocalcinosis of the knee or wrist.

CONCLUSION

CPPD crystal formation seems to be a late and frequent event of tophus maturation, occurring more frequently with aging, and could contribute to the speed of tophus dissolution and the apparent persistence of tophus sometimes observed even after effective, long-lasting urate-lowering therapy.

UltraSound evaluation in follow-up of urate-lowering therapy in gout phase 2 (USEFUL-2): Duration of flare prophylaxis

OBJECTIVES

To determine whether changes in ultrasonography (US) features of monosodium urate crystal deposition is associated with the number of gouty flares after stopping gout flare prophylaxis.

METHODS

We performed a 1-year multicentre prospective study including patients with proven gout and US features of gout. The first phase of the study was a 6-month US follow-up after starting urate-lowering therapy (ULT) with gout flare prophylaxis. After 6 months of ULT, gout flare prophylaxis was stopped, followed by a clinical follow-up (M6 to 12) and ULT was maintained. Outcomes were the proportion of relapsing patients between M6 and M12 according to changes of US features of gout and determining a threshold decrease in tophus size according to the probability of relapse.

RESULTS

We included 79 gouty patients [mean (±SD) age 61.8±14 years, 91% males, median disease duration 4 (IQR 1.5;10) years]. Among the 49 completers at M12, 23 (47%) experienced relapse. Decrease in tophus size ≥50% at M6 was more frequent without than with relapse (54% vs. 26%, P=0.049). On ROC curve analysis, a threshold decrease of 50.8% in tophus size had the best sensitivity/specificity ratio to predict relapse [AUC 0.649 (95% confidence interval 0.488; 0.809)]. Probability of relapse was increased for patients with a decrease in tophus size <50% between M0 and M6 [OR 3.35 (95% confidence interval 0.98; 11.44)].

CONCLUSION

A high reduction in US tophus size is associated with lower probability of relapse after stopping gout prophylaxis. US follow-up may be useful for managing ULT and gout flare prophylaxis.

A cross-sectional study of 502 patients found a diffuse hyperechoic kidney medulla pattern in patients with severe gout

We have previously shown that ultrasonography can detect hyperechogenic crystal deposits in the kidney medulla of patients with gout. In this cross-sectional study we investigated the frequency and clinical correlates of hyperechogenic kidney medulla in 502 consecutive primary consultants for gout (ACR/EULAR criteria) at the Vien Gut medical center in Ho Chi Minh City, Vietnam. None of these patients received urate-lowering drugs. Kidney medulla echogenicity on B-mode ultrasonography was compared to that of the kidney cortex. Overall, 36% patients showed a hyperechoic pattern of Malpighi pyramids. On univariate analysis, the pattern was significantly associated with age, estimated gout duration, steroid-dependency, clinical tophi, urate arthropathy, double contour thickness at the scanned joints, coronary heart disease, arterial hypertension, hyperuricemia, proteinuria, leukocyturia, and decreased estimated glomerular filtration rate. On multivariable analysis, the hyperechoic pattern was associated with estimated disease duration, clinical tophi, urate arthropathy, double contour thickness and decreased estimated glomerular filtration rate. No hyperechoic pattern was observed in 515 consecutive consultants without gout. Thus, hyperechoic kidney medulla was frequently demonstrated in Vietnamese patients with tophaceous gout and associated with features of tubulointerstitial nephritis. This finding revives the hypothesis of microcrystalline nephropathy of gout, predominantly seen in untreated gouty patients, which could be an important target for urate-lowering therapy.

Risk factors for cutaneous reactions to allopurinol in Kinh Vietnamese: results from a case-control study

OBJECTIVE

The aim of this study was to investigate risk factors for cutaneous adverse reactions (CARs) in Kinh Vietnamese.

METHODS

All patients were prospectively recruited in Ho Chi Minh City. Presence of the HLA-B*58:01 allele was determined by real-time PCR-sequence-specific amplification by using the PG5801 Detection Kit (Pharmigene, Taipei). Patients with severe (SCARs) and mild (MCARs) CARs and controls were compared for differences in features prospectively collected, and odds ratios (ORs) with 95% confidence intervals (CIs) were estimated.

RESULTS

On comparing 32 patients with SCARs and 395 tolerant controls, we identified eight strong risk factors: increased age (OR 15.1 [95% CI 5.8-40.1], P < 0.0001), female sex (OR 333 [40-43,453], P < 0.0001), allopurinol for asymptomatic hyperuricemia (OR 955 [120-125,847], P < 0.0001), allopurinol starting dose > 150 mg (OR 316 [101-122], P < 0.0001), diuretics intake (OR 304 [35-40,018], P < 0.0001), eGFR < 60 ml/min/1.73 m² (OR 100 [32-353], P < 0.0001), history of allopurinol-induced skin reaction (OR 78 [6-10,808], P = 0.004), and HLA-B*58:01 carriage (OR 147 [45-746], P < 0.0001). HLA-B*58:01 allele frequency in controls was 7.3%. For MCARs (n = 74), risk factors were eGFR < 60 ml/min/1.73 m² (OR 4.9 [1.61-14.6], P = 0.006), history of allopurinol-induced skin reaction (OR 27 [2-3777], P = 0.01), and asymptomatic hyperuricemia (OR 27 [2-3777], P = 0.01).

CONCLUSION

This study confirmed 8 risk factors, including HLA-B*58:01, for SCARs and identified 3 risk factors for MCARs in Kinh Vietnamese. HLA-B*58:01 genotyping could guide the indication for allopurinol in Kinh Vietnamese patients with gout.

Gout and pseudo-gout-related crystals promote GLUT1-mediated glycolysis that governs NLRP3 and interleukin-1β activation on macrophages

OBJECTIVE

Macrophage activation by monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals mediates an interleukin (IL)-1β-dependent inflammation during gout and pseudo-gout flare, respectively. Since metabolic reprogramming of macrophages goes along with inflammatory responses dependently on stimuli and tissue environment, we aimed to decipher the role of glycolysis and oxidative phosphorylation in the IL-1β-induced microcrystal response.

METHODS

Briefly, an in vitro study (metabolomics and real-time extracellular flux analysis) on MSU and CPP crystal-stimulated macrophages was performed to demonstrate the metabolic phenotype of macrophages. Then, the role of aerobic glycolysis in IL-1β production was evaluated, as well in vitro as in vivo using ¹⁸F-fluorodeoxyglucose positron emission tomography imaging and glucose uptake assay, and molecular approach of glucose transporter 1 (GLUT1) inhibition.

RESULTS

We observed that MSU and CPP crystals led to a metabolic rewiring toward the aerobic glycolysis pathway explained by an increase in GLUT1 plasma membrane expression and glucose uptake on macrophages. Also, neutrophils isolated from human synovial fluid during gout flare expressed GLUT1 at their plasma membrane more frequently than neutrophils isolated from bloodstream. Both glucose deprivation and treatment with either 2-deoxyglucose or GLUT1 inhibitor suppressed crystal-induced NLRP3 activation and IL-1β production, and microcrystal inflammation in vivo.

CONCLUSION

In conclusion, we demonstrated that GLUT1-mediated glucose uptake is instrumental during the inflammatory IL-1β response induced by MSU and CPP crystals. These findings open new therapeutic paths to modulate crystal-related inflammation.

THU0422 CALCIUM PYROPHOSPHATE CRYSTAL DEPOSITION WITHIN TOPHUS LOBULE: A FREQUENT ASSOCIATION OBSERVED IN LONG-TIME COURSE TOPHI

Background:

Calcium pyrophosphate (CPP) crystals and monosodium urate (MSU) crystals are frequently found in the same synovial fluids of gouty patients suggesting an interaction in crystal formation and deposition. This association has never been reported in tophus.

Objectives:

we aimed to describe the prevalence of CPP crystal deposition in tophus and to determine the associated risk factors.

Methods:

22 tophi consecutively harvested were fixed in 4% paraformaldehyde and embedded in paraffin. 5-µm thick sections were analyzed by compensated polarized microscopy (CPM) after hematoxylin and eosin staining. Characterization of CPP crystals were performed by scan electronic microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Clinical characteristics were compared between patients having tophus with CPP deposition and patients having tophus without CPP crystals.

Results:

All tophi appeared multi-lobulated depositions of MSU crystals separated by fibrous tissue and surrounded by a foreign giant cell reaction. CPP crystals were identified in few lobules of 5 tophi (22.7%) harvested from 3 great toes, 1 elbow bursa and 1 finger of 5 patients. CPP crystals formed aggregate deposition within the lobule of MSU crystals. Both monoclinic and triclinic CPP crystal phases were identified by CPM, SEM and FTIR. Tophi were harvested from 22 male gouty patients with a mean age of 50.8 (28-66) years and a mean BMI of 24.2 kg/m2 (18.9-29.4). Mean serum urate level (SUL) was 499 ± 107 µmol/L. 59% of patients had chronic renal disease stage 2 or 3, 40.9% dyslipidemia, 22.7% type 2 diabetes mellitus, 13.6% hypertension and 50% obesity. Patients with tophi containing CPP deposition were older (61.2 [56-66] vs 47.8 [28-64] years, p=0.009) and had a longer gout duration (19 [10-31] vs 9 [3-20] years, p= 0.007) and tophus duration (11.4 [8-16] vs 4.5 [1-9] years, p< 0.0001) than patients with tophi alone. Tophi did not display calcification on radiographies performed before surgery. However, the density of tophi containing CPP crystal deposition was higher than the density of tophi without CPP crystals (51 [25-100] vs 21.5% [0-40], p=0.009). The proportion of bone erosion and gout arthropathy was similar between the two groups. Similarly, no difference was observed for SUL (467 ± 43 vs 509 ± 109 µmol/L), estimated glomerular filtration rate (76.6 ± 11.9 vs 74.9 ± 15.7 ml/min/1.73m2) and prevalence of comorbidities. Interestingly, no calcification was detected on knee and wrist radiographies of patients with tophi containing CPP deposition.

Conclusion:

These results reported for the first time, in a small sample size, that CPP crystal deposition occurred within tophus lobules. They suggested that long-time course tophi might act as a facilitating agent of CPP nucleation. This hypothesis needs specific confirmation studies

Disclosure of Interests: :

None declared

2020 Recommendations from the French Society of Rheumatology for the management of gout: Management of acute flares

OBJECTIVE

To develop French Society of Rheumatology-endorsed recommendations for the management of gout flares.

METHODS

These evidence-based recommendations were developed by 9 rheumatologists (academic or community-based), 3 general practitioners, 1 cardiologist, 1 nephrologist and 1 patient, using a systematic literature search, one physical meeting to draft recommendations and 2 Delphi rounds to finalize them.

RESULTS

A set of 4 overarching principles and 4 recommendations was elaborated. The overarching principles emphasize the importance of patient education, including the need to auto-medicate for gout flares as early as possible, if possible within the first 12h after the onset, according to a pre-defined treatment. Patients must know that gout is a chronic disease, often requiring urate-lowering therapy in addition to flare treatment. Comorbidities and the risk of drug interaction should be screened carefully in every patient as they may contraindicate some anti-inflammatory treatments. Colchicine must be early prescribed at the following dosage: 1mg then 0.5mg one hour later, followed by 0.5mg,2 to 3 times/day over the next days. In case of diarrhea, which is the first symptom of colchicine poisoning, dosage must be reduced. Colchicine dosage must also be reduced in patients with chronic kidney disease or taking drugs, which interfere with its metabolism. Other first-line treatment options are systemic/intra-articular corticosteroids, or non-steroidal anti-inflammatory agents (NSAIDs). IL-1 inhibitors can be considered as a second-line option in case of failure, intolerance or contraindication to colchicine, corticosteroids and NSAIDs. They are contraindicated in cases of infection and neutrophil blood count should be monitored.

CONCLUSION

These recommendations aim to provide strategies for the safe use of anti-inflammatory agents, in order to improve the management of gout flares.

2020 recommendations from the French Society of Rheumatology for the management of gout: Urate-lowering therapy

OBJECTIVE

To develop French Society of Rheumatology-endorsed recommendations for the management of urate-lowering therapy (ULT).

METHODS

Evidence-based recommendations were developed by 9 rheumatologists (academic or community-based), 3 general practitioners, 1 cardiologist, 1 nephrologist and 1 patient, using a systematic literature search, one physical meeting to draft recommendations and two Delphi rounds to finalize them.

RESULTS

A set of 3 overarching principles and 5 recommendations was elaborated. The overarching principles emphasize the importance of patient education, especially the need for explaining the objective of lowering serum urate (SU) level to obtain crystal dissolution, clinical symptoms disappearance and avoidance of complications. ULT is indicated as soon as the diagnosis of gout is established. SU level must be decreased below 300μmol/l (50mg/l) in all gout patients or at least below 360μmol/l (60ml/l) when the 300μmol/l target cannot be reached, and must be maintained at these targets and monitored life-long. The choice of the ULT primarily relies on renal function: in patients whose estimated glomerular filtration rate (eGFR) is above 60ml/min/1.73m², first-line ULT is allopurinol; in those with eGFR between 30 and 60ml/min/1.73m², allopurinol use must be cautious and febuxostat can be considered as an alternative; and in those whose eGFR is below 30ml/min/1.73m², allopurinol must be avoided and febuxostat should be preferred. Prophylaxis of ULT-induced gout flares involves progressive increase of ULT dosage and low-dose colchicine for at least 6 months. Cardiovascular risk factors and diseases, the metabolic syndrome and chronic kidney disease must be screened and managed.

CONCLUSION

These recommendations aim to provide simple and clear guidance for the management of ULT in France.

The role of febuxostat in gout

PURPOSE OF REVIEW

Concerns about the cardiovascular safety of febuxostat lead to reconsideration of the place of febuxostat in the management of gout.

RECENT FINDINGS

The CARES trial is a randomized controlled trial mandated by the FDA to compare the cardiovascular safety of febuxostat and allopurinol in the management of gout. About 6190 patients with gout and major cardiovascular disease, randomly assigned to allopurinol or febuxostat, were prospectively followed up for a median of 32 months. No difference was noted in the occurrence of the primary end-point event, a composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, or unstable angina with urgent revascularization, but cardiovascular death was significantly more common in the febuxostat group (4.3%) as compared with the allopurinol group (3.2%) (P = 0.03).

SUMMARY

Present guidelines on the management of gout should be revised in view of recent findings. Allopurinol could be recommended as the sole first-line urate-lowering drug (ULD) in patients with no contraindication. In patients contraindicated to allopurinol, uricosurics could be preferred to febuxostat as first-line ULDs in patients with cardiovascular disease/risk factors and no history of uric acid stones.

Ultrasound evaluation in follow-up of urate-lowering therapy in gout: the USEFUL study

OBJECTIVES

We aimed to determine the ability of ultrasonography (US) to show disappearance of urate deposits in gouty patients requiring urate-lowering therapy (ULT).

METHODS

We performed a 6-month multicentre prospective study including patients with: proven gout; presence of US features of gout (tophus and/or double contour sign) at the knee and/or first metatarsophalangeal joints; and no current ULT. US evaluations were performed at baseline and at months 3 and 6 (M3, M6) after starting ULT. Outcomes were: the change in US features of gout at M6 according to final (M6) serum urate (SU) level (high, > 360 μmol/l, i.e. > 6 mg/dl; low, 300-360 μmol/l, i.e. 5-6 mg/dl; very low, < 300 μmol/l, i.e. < 5 mg/dl); and correlation between changed US features and final SU level.

RESULTS

We included 79 gouty patients (mean ± s.d., age 61.8 (14) years, 91% males, disease duration 6.3 (6.1) years). Baseline SU level was 530 ± 97 µmol/l (i.e. 8.9 mg/dl ± 1.6mg/dl). At least one US tophus and double contour sign was observed in 74 (94%) and 68 (86%) patients, respectively. Among the 67 completers at M6, 18 and 39 achieved a very low and low SU level, respectively. We found a significant decrease in US features of gout among patients with the lowest SU level (P < 0.001). Final M6 SU level was positively correlated with decreased size of tophus (r = 0.54 [95% CI: 0.34, 0.70], P < 0.0001), and inversely correlated with proportion of double contour sign disappearance (r=-0.59 [-0.74, -0.40]).

CONCLUSION

US can show decreased urate deposition after ULT, which is correlated with decreased SU level. The responsiveness of US in gout is demonstrated and can be useful for gout follow-up and adherence to ULT.

A single intra-articular injection of 2.0% non-chemically modified sodium hyaluronate vs 0.8% hylan G-F 20 in the treatment of symptomatic knee osteoarthritis: A 6-month, multicenter, randomized, controlled non-inferiority trial

OBJECTIVES

The aim of the study was to demonstrate the non-inferiority of a single intra-articular injection of 2.0% non-chemically modified sodium hyaluronate (SH) vs 0.8% hylan G-F 20 (control) in symptomatic knee osteoarthritis.

DESIGN

This was a double-blind, randomized, controlled trial conducted in patients with painful tibiofemoral osteoarthritis (American College of Rheumatology criteria) with insufficient response or intolerance to first-line analgesics and regular non-steroidal anti-inflammatory drugs. Subjects received a single intra-articular injection of either SH or hylan G-F 20. The primary outcome was the 6-month change from baseline in the Western Ontario and McMaster Universities Osteoarthritis Index pain subscale (WOMAC A), with a pre-specified lower margin for non-inferiority of 8 mm.

RESULTS

Of the 292 patients randomized (SH: 144), 288 received an injection (SH: 142), 266 completed the study (SH: 134). In the Per Protocol dataset (SH: 113, control: 112), the WOMAC A change at 6 months was -34.3 mm (95% confidence interval (CI): -37.8, -30.8) and -36.2 mm (95% CI: -40.3, -32.1) for the SH and hylan G-F 20 patients, respectively (P = 0.5). The intergroup difference was -1.9 mm (95% CI: -7.3, 3.5). Results were similar in the Full Analysis Set (SH: 139, control: 141) with a difference between the groups of -2.9 mm (95% CI: -7.9, 2.2). A total of 31.3% of the injected patients reported a treatment-emergent adverse event, including injection site reactions (pain, inflammation or effusion) which occurred in 8.5% of the SH patients vs 13.0% of the hylan G-F 20 patients. No serious reactions were reported.

CONCLUSIONS

This clinical trial demonstrated the non-inferiority of a single intra-articular injection of SH vs hylan G-F 20 on the WOMAC A change from baseline at 6 months.

Gout, Hyperuricemia, and Crystal-Associated Disease Network Consensus Statement Regarding Labels and Definitions for Disease Elements in Gout

OBJECTIVE

The language currently used to describe gout lacks standardization. The aim of this project was to develop a consensus statement on the labels and definitions used to describe the basic disease elements of gout.

METHODS

Experts in gout (n = 130) were invited to participate in a Delphi exercise and face-to-face consensus meeting to reach consensus on the labeling and definitions for the basic disease elements of gout. Disease elements and labels in current use were derived from a content analysis of the contemporary medical literature, and the results of this analysis were used for item selection in the Delphi exercise and face-to-face consensus meeting.

RESULTS

There were 51 respondents to the Delphi exercise and 30 attendees at the face-to-face meeting. Consensus agreement (≥80%) was achieved for the labels of 8 disease elements through the Delphi exercise; the remaining 3 labels reached consensus agreement through the face-to-face consensus meeting. The agreed labels were monosodium urate crystals, urate, hyperuric(a)emia, tophus, subcutaneous tophus, gout flare, intercritical gout, chronic gouty arthritis, imaging evidence of monosodium urate crystal deposition, gouty bone erosion, and podagra. Participants at the face-to-face meeting achieved consensus agreement for the definitions of all 11 elements and a recommendation that the label "chronic gout" should not be used.

CONCLUSION

Consensus agreement was achieved for the labels and definitions of 11 elements representing the fundamental components of gout etiology, pathophysiology, and clinical presentation. The Gout, Hyperuricemia, and Crystal-Associated Disease Network recommends the use of these labels when describing the basic disease elements of gout.

Shoulder adhesive capsulitis: diagnostic value of active and passive range of motion with volume of gleno-humeral capsule as a reference

BACKGROUND

The diagnosis of adhesive capsulitis is currently based on restricted range of motion (ROM) but its diagnostic value has only been rarely investigated.

AIM

The aim of this study is to assess the diagnostic value of active global and passive gleno-humeral ROM to diagnose shoulder adhesive capsulitis.

DESIGN

Cross-sectional descriptive study.

SETTING

One French center for Rehabilitation Medicine.

POPULATION

Patients referred for treatment of shoulder adhesive capsulitis in our center were included. Inclusion criteria were: shoulder pain; limitation of active global ROM (abduction or flexion <180°); limitation of passive gleno-humeral ROM (abduction or flexion <90° or 25% reduction at less of lateral rotation versus the opposite shoulder); no gleno-humeral arthropathy on radiography.

METHODS

The volume of the gleno-humeral capsule was assessed during a procedure of arthro-distension. The reference criterion for adhesive capsulitis was a volume <12 mL. We analyzed the correlation between the parameters of mobility and the volume of the gleno-humeral capsule; and the positive predictive value (PPV) of inclusion criteria, with the reference criterion for the diagnosis of adhesive capsulitis.

RESULTS

We included 38 patients. Passive gleno-humeral ROM in abduction only was correlated with volume of the gleno-humeral capsule: r=0.33, P=0.043. The PPV of inclusion criteria was 82% for the diagnosis of shoulder adhesive capsulitis. Rather than 90°, when we considered 80°, 60° and 40° as the threshold of passive gleno-humeral ROM in abduction, the PPV increased from 83% to 100%.

CONCLUSIONS

Passive gleno-humeral ROM in abduction is correlated with volume of the gleno-humeral capsule. The PPV is high for active global and passive gleno-humeral ROM for diagnosis of shoulder adhesive capsulitis.

CLINICAL REHABILITATION IMPACT

Limitation of active and passive shoulder ROM, especially passive abduction gleno-humeral, is a good criterion to diagnose shoulder adhesive capsulitis, in patients with shoulder pain and no gleno-humeral arthropathy on radiography.

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.

2018 updated European League Against Rheumatism evidence-based recommendations for the diagnosis of gout

Although gout is the most common inflammatory arthritis, it is still frequently misdiagnosed. New data on imaging and clinical diagnosis have become available since the first EULAR recommendations for the diagnosis of gout in 2006. This prompted a systematic review and update of the 2006 recommendations. A systematic review of the literature concerning all aspects of gout diagnosis was performed. Recommendations were formulated using a Delphi consensus approach. Eight key recommendations were generated. A search for crystals in synovial fluid or tophus aspirates is recommended in every person with suspected gout, because demonstration of monosodium urate (MSU) crystals allows a definite diagnosis of gout. There was consensus that a number of suggestive clinical features support a clinical diagnosis of gout. These are monoarticular involvement of a foot or ankle joint (especially the first metatarsophalangeal joint); previous episodes of similar acute arthritis; rapid onset of severe pain and swelling; erythema; male gender and associated cardiovascular diseases and hyperuricaemia. When crystal identification is not possible, it is recommended that any atypical presentation should be investigated by imaging, in particular with ultrasound to seek features suggestive of MSU crystal deposition (double contour sign and tophi). There was consensus that a diagnosis of gout should not be based on the presence of hyperuricaemia alone. There was also a strong recommendation that all people with gout should be systematically assessed for presence of associated comorbidities and risk factors for cardiovascular disease, as well as for risk factors for chronic hyperuricaemia. Eight updated, evidence-based, expert consensus recommendations for the diagnosis of gout are proposed.

Comparative effectiveness of rituximab, abatacept, and tocilizumab in adults with rheumatoid arthritis and inadequate response to TNF inhibitors: prospective cohort study

OBJECTIVE

To compare the effectiveness and safety of three non-tumour necrosis factor (TNF) α inhibitors (rituximab, abatacept, and tocilizumab) in the treatment of rheumatoid arthritis.

DESIGN

Population based prospective study.

SETTING

53 university and 54 non-university clinical centres in France.

PARTICIPANTS

3162 adults (>18 years) with rheumatoid arthritis according to 1987 American College of Rheumatology criteria, enrolled in one of the three French Society of Rheumatology registries; who had no severe cardiovascular disease, active or severe infections, or severe immunodeficiency, with follow-up of at least 24 months.

INTERVENTION

Initiation of intravenous rituximab, abatacept, or tocilizumab for rheumatoid arthritis.

MAIN OUTCOME MEASURE

The primary outcome was drug retention without failure at 24 months. Failure was defined as all cause death; discontinuation of rituximab, abatacept, or tocilizumab; initiation of a new biologic or a combination of conventional disease modifying antirheumatic drugs; or increase in corticosteroid dose >10 mg/d compared with baseline at two successive visits. Because of non-proportional hazards, treatment effects are presented as life expectancy difference without failure (LED_wf), which measures the difference between average duration of survival without failure.

RESULTS

Average durations of survival without failure were 19.8 months for rituximab, 15.6 months for abatacept, and 19.1 months for tocilizumab. Average durations were greater with rituximab (LED_wf 4.1, 95% confidence interval 3.1 to 5.2) and tocilizumab (3.5, 2.1 to 5.0) than with abatacept, and uncertainty about tocilizumab compared with rituximab was substantial (-0.7, -1.9 to 0.5). No evidence was found of difference between treatments for mean duration of survival without death, presence of cancer or serious infections, or major adverse cardiovascular events.

CONCLUSION

Among adults with refractory rheumatoid arthritis followed-up in routine practice, rituximab and tocilizumab were associated with greater improvements in outcomes at two years compared with abatacept.

Tendon thickening in dialysis-related joint arthritis is due to amyloid deposits at the surface of the tendon

OBJECTIVES

Beta-2-microglobulin (β2M) dialysis-related amyloidosis (DRA), a disabiliting joint disease, has been initially reported in patients under long-term dialysis. The incidence and prevalence has significantly decreased with the improvement in dialysis techniques. Here, we attempted to clarify the clinical and MRI features to improve the diagnosis.

METHODS

We retrospectively reviewed the files of 19 patients under dialysis treatment referred for suspicion of β2M DRA. The diagnosis was based on MRI criteria (low signal intensity on both T1- and T2-weighted MR sequences). MRI analysis included a scoring of the several joint lesions. Scores were quantified according to a severity scale (0 to 3).

RESULTS

Patients had a mean age of 66.0 ± 10.5 years and mean dialysis duration of 23.7 ± 10.5 years. DRA affected mainly large joints (shoulder in 73.7%, hip in 47.3%) and spine (36.8%). MRI images for 8 shoulders, 8 hips, and 3 spines were analysed. Amyloid synovitis was present in all cases, with high mean scores in the three sites. In all joints, the most common lesions were tendon thickening (68.4%) and bone erosions (68.4%). The mean tendon thickening score was high, particularly at the shoulders and also at the spine. Bone erosions were most frequent in the shoulder and pelvis.

CONCLUSION

In patients under long-term dialysis, β2M DRA involves large joints but also the spine. Special awareness should be drawn by the thickening of the tendon. MRI is required to characterize the pattern of the lesions and to achieve the diagnosis.

Probing The Relation Between Vitamin D Deficiency and Progression of Medial Femoro-tibial Osteoarthitis of the Knee

OBJECTIVE

To compare serum 25 OH vitamin D (25 (OH) D) levels between medial femoro-tibial knee osteoarthritis (OA) patients and controls, and to detect structural progression in patients with mild to moderate knee osteoarthritis in relation to baseline 25(OH) D levels in a oneyear longitudinal prospective cohort study.

METHODS

Thirty eight patients with medial femoro-tibial knee OA according to the ACR criteria and no knee malalignement, and 20 age, sex and BMI-matched pain free controls were included in the vitamin D study. All included OA patients had radiographic Kellgren and Lawrence grades 2 or 3. Baseline serum levels of 25(OH) D, and the "Benefiting from ultraviolet index "(BFUI) score were determined; serum parathormone, total alkaline phosphatase, calcium and phosphorus were measured. In the OA progression study, OA patients were divided into 2 groups according to 25 (OH) D level using a cutoff of 10 ng/ml to identify their status. MRIs were done at baseline and repeated after 12 months with scoring system according to Boston Leeds osteoarthritis knee score (BLOKS). During the study period, the patients were not supplemented with 25(OH)D.

RESULTS

The mean values of Vitamin D were statistically lower in the OA patient group than in controls (8.64 ± 6.42 vs. 14.84±0.87 pg/mL, P =0.0295). The BFUI score overall correlated with 25 (OH) D status. Eight patients did not complete the study so only thirty OA patients underwent the 2 MRIs. Of those, 21 had 25(OH) D levels <10 ng/ml, while 9 had levels >10 ng/ml. A significant progression of the medial meniscal grading from baseline to 1 year was seen in the patients with 25(OH)D levels <10 ng/ml as compared to the others (Wilcoxon Z= -3.556 P<0.001).

CONCLUSION

25 (OH) D levels were significantly decreased in knee OA patients. Significant deterioration of the medial menisci was observed in OA patients with 25 (OH)D levels <10 ng/ml suggesting that Vit D deficiency may play a role in the progression of medial femoro-tibial OA.

Accuracy of the HumaSensplus point-of-care uric acid meter using capillary blood obtained by fingertip puncture

BACKGROUND

The uric acid (UA) level in patients with gout is a key factor in disease management and is typically measured in the laboratory using plasma samples obtained after venous puncture. This study aimed to assess the reliability of immediate UA measurement with capillary blood samples obtained by fingertip puncture with the HumaSensplus point-of-care meter.

METHODS

UA levels were measured using both the HumaSensplus meter in the clinic and the routine plasma UA method in the biochemistry laboratory of 238 consenting diabetic patients. HumaSensplus capillary and routine plasma UA measurements were compared by linear regression, Bland-Altman plots, intraclass correlation coefficient (ICC), and Lin's concordance coefficient. Values outside the dynamic range of the meter, low (LO) or high (HI), were analyzed separately. The best capillary UA thresholds for detecting hyperuricemia were determined by receiver operating characteristic (ROC) curves. The impact of potential confounding factors (demographic and biological parameters/treatments) was assessed. Capillary and routine plasma UA levels were compared to reference plasma UA measurements by liquid chromatography-mass spectrometry (LC-MS) for a subgroup of 67 patients.

RESULTS

In total, 205 patients had capillary and routine plasma UA measurements available. ICC was 0.90 (95% confidence interval (CI) 0.87-0.92), Lin's coefficient was 0.91 (0.88-0.93), and the Bland-Altman plot showed good agreement over all tested values. Overall, 17 patients showed values outside the dynamic range. LO values were concordant with plasma values, but HI values were considered uninterpretable. Capillary UA thresholds of 299 and 340 μmol/l gave the best results for detecting hyperuricemia (corresponding to routine plasma UA thresholds of 300 and 360 μmol/l, respectively). No significant confounding factor was found among those tested, except for hematocrit; however, this had a negligible influence on the assay reliability. When capillary and routine plasma results were discordant, comparison with LC-MS measurements showed that plasma measurements had better concordance: capillary UA, ICC 0.84 (95% CI 0.75-0.90), Lin's coefficient 0.84 (0.77-0.91); plasma UA, ICC 0.96 (0.94-0.98), Lin's coefficient 0.96 (0.94-0.98).

CONCLUSIONS

UA measurements with the HumaSensplus meter were reasonably comparable with those of the laboratory assay. The meter is easy to use and may be useful in the clinic and in epidemiologic studies.