AB1040 ASSOCIATION OF Q141K POLYMORPHISM OF ABCG2 GENE WITH THE EFFECTIVENESS OF URATE-LOWERING THERAPY IN PATIENTS WITH GOUT (PILOT STUDY)

Background

The effectiveness of allopurinol in pts with gout depends on genetic factors (GF) [1]. How GF works on probability of the target serum uric acid (sUA) level achievement is not studied.

Objectives

To study the opportunity of the target sUA level achievement in pts with gout while taking allopurinol or febuxostat, depending on the polymorphism (rs2231142) of the ABCG2 gene.

Methods

The study included 82 pts with gout aged ≥18 yrs who did not take urate-lowering drugs (ULD) and had sUA level >360 µmol/l. Initially all patients were prescribed allopurinol 100 mg/day, than the dose was up-titrared to achieve the target sUA level (<360 µmol/l or <300 µmol/l in pts with chronic tophaceous gout). Maximum dosage was 900 mg/day; in pts with glomerular filtration rate (GFR) <60 ml/min/1.73 m2 - 300 mg/day. Pts who did not achieve the target sUA level while using allopurinol were prescribed febuxostat 80 mg/day, which, if necessary, was increased to 120 mg/day. Each patient was followed up until the target sUA level was achieved.

All pts underwent genotyping of the С>А (rs2231142) polymorphism of the ABCG2 gene. During the study we compared: the probability of achieving the target sUA level, the average values of the sUA level decline, the average doses of ULD in pts with different genotypes (CC, CA, AA) of the ABCG2 gene. Statistical analysis was carried out using the Statistica 12.0 software package, and descriptive statistics methods.

Results

The target sUA level was defined as <300 µmol/l in 45 (55%) of 82 pts, as <360 µmol/l in 37 (45%) pts. In 26 pts, the dose of allopurinol did not exceed 300 mg/day. In 28 (34%) pts on allopurinol therapy, the target level of sUA was achived. In 54 (66%) pts allopurinol was replaced with febuxostat, while in 22 (41%) of them, the level of sUA decreased and was below the target.

The CC genotype of the ABCG2 gene was found in 51 (62%) pts, the CA genotype in 30 (37%) pts, and the minor AA genotype in 1 (1%) pt. The opportunity of the target sUA level achievement during the allopurinol therapy in carriers of the homozygous CC genotype and CA or AA genotypes did not differ: 17 (33%) and 11 (35%) cases, respectively. It turned out that CA and AA pts required a significantly higher dose of allopurinol (365±102 mg/day) than CC pts (290±85 mg/day), p=0.002. Of 54 pts treated with febuxostat who did not achieve the target sUA level, 30 (56%) pts had the CC genotype and 24 (44%) pts had the CA genotype. The opportunity of the target sUA level achievement was comparable (p=0.22).

Conclusion

The opportunity of achieving the target sUA level in pts with gout taking allopurinol is not associated with the C>A polymorphism of the ABCG2 gene, but the presence of the CA and AA genotypes is associated with the need to prescribe large doses of allopurinol.

References

[1]Wen CC, Yee SW, Liang X et al. Genome-wide association study identifies ABCG2 (BCRP) as an allopurinol transporter and a determinant of drug response. Clin Pharmacol Ther. 2015 May;97(5):518-25. doi: 10.1002/cpt.89

Disclosure of Interests

Maxim Eliseev Speakers bureau: Berlin Chemie Menarini Group, Sobi, EGIS, CSC, MosFarma, Alium Group, Maria Chikina: None declared, Olga Sheliabina Speakers bureau: Berlin Chemie Menarini Group, Elena Cheremushkina: None declared

AB1045 QUALITY OF LIFE IN PATIENTS WITH GOUT TAKING URATE-LOWERING DRUGS, DEPENDING ON THE ACHIEVEMENT OF THE TARGET LEVEL OF SERUM URIC ACID

Background

Intake of urate-lowering drugs (ULD) leads to an improvement in the quality of life (QoL) in pts with gout. However, it is not clear to what extend the QoL is changed in pts who did not achieve the target level of serum uric acid (sUA).

Objectives

to evaluate the dynamics of the QoL in pts, taking ULD, who have achieved and have not achieved the target sUA level.

Methods

98 pts with gout were included in the prospective study. The follow-up period was 24 months, allopurinol or febuxostat at doses sufficient to achieve the target sUA level (<360 µmol/l) were used. The maximum daily dose of allopurinol was 900 mg/day, febuxostat - 120 mg/day. Pts who did not achieve the target sUA level continued taking ULD at the maximum dosages. The values of the Qol in dynamics were calculated using the SF-36v2 questionnaire. The assessment of the QoL was carried out separately in pts who achieved and did not achieve the target level of sUA. The frequency of exacerbations of arthritis was also assessed. Statistica 12.0 package was used for statistical data processing.

Results

69 of 98 (70%) pts achieved the target sUA level, wherein allopurinol was taken by 46 pts, febuxostat – 34 pts. Pts who achieved the target level of sUA after 6 mo. of ULD usage, demonstrated a significant improvement in the physical health (PH), including physical functioning (PF), role limitations due to physical functioning (RP), general health (GH), as well as vitality (VT) (p<0.05 for all). After 12 and 24 mo. improvement was achieved in RH, GH and PF (p<0.01), RP, bodily pain intensity (BP) and VT (p<0.05). General mental health (MH), role-emotional functioning (RE) and social functioning (SF) were unchanged throughout the study. Pts who did not achieve the target sUA level after 6 and 12 mo. significantly improved: PF, RP (p<0.05 for all). After 24 months, for all QoL parameters, the values did not differ from the initial ones. The frequency of arthritis exacerbation in pts who achieved the target sUA level decreased from 3.1±1.6 cases per year to 0.9±1.1 cases per year (p=0.0013); in those who did not achieve - from 3.1±1.9 cases per year to 2.4±1.6 cases per year (p=0.047).

Conclusion

: The QoL in gout pts who achieved target sUA level continues to improve during the first year of ULD intake. Even if the target sUA level is not achieved, the QoL of patients with gout treated with ULD remains stable for at least 2 years of therapy. This predetermines the need to use maximum daily doses of ULD, even if the target serum UA level is not achieved.

Disclosure of Interests

Maria Chikina: None declared, Olga Sheliabina Speakers bureau: Berlin Chemie Menarini Group, Maxim Eliseev Speakers bureau: Berlin Chemie Menarini Group, Sobi, EGIS, CSC, MosFarma, Alium Group

POS0277 EFFECT OF COLCHICINE THERAPY ON ATHEROSCLEROSIS-RELATED CARDIOVASCULAR OUTCOMES IN PATIENTS WITH CALCIUM PYROPHOSPHATE CRYSTAL DEPOSITION DISEASE

Background

anti-inflammatory therapy supposed to influence the rate of cardiovascular events development in pts with calcium pyrophosphate deposition disease (CPPD).

Objectives

To assess the effect of colchicine, hydroxychloroquine, and methotrexate on cardiovascular outcomes (CVO) in CPPD pts.

Methods

The study included 305 pts with CPPD: 115 (37.70%) men, 190 (62.30%) women. The average follow-up period was 3.9±2.7 yrs. Among the factors influencing CVO were considered: gender, age, smoking, alcohol intake ≥20 standard doses/week, hypertension, history of cardiovascular disease (CVD): (ischemic heart disease (CHD), acute myocardial infarction myocardial infarction (AMI), acute cerebrovascular insufficiency (ACV), chronic heart failure (CHF) >3 grade, NYHA), diabetes mellitus (DM), BMI >25 kg/m2 and >30 kg/m2, cholesterol level >5.1 mmol/l, GFR <60 ml/min/1.73 m2, serim uric acid (sUA) > 360 µmol/l, hypercalcemia (serum calcium> 2.62 mmol/l), CRP> 2 mg/l, hyperparathyroidism (parathyroid hormone> 65 pg/ml), phenotypes of CPPD (asymptomatic, osteoarthritis with calcium pyrophosphate crystals (OA with CPP crystals), chronic arthritis, acute arthritis), taking colchicine, hydroxychloroquine and methotrexate, glucocorticoids (GCs) and non-steroidal anti-inflammatory drugs (NSAIDs).

Information about mortality, regardless of cause, was noting down throughout the follow-up period.

The causes of death were determined on the patient’s death certificate, and then classified according to the International Classification of Diseases of the 10-th Revision (ICD-10) All newly developed cases of non-fatal cardiovascular events were identified on the basis of medical documentation. The odds ratio (OR) with a 95% confidence interval of developing cardiovascular events was calculated. Statistica 12.0 package was used for statistical data processing.

Results

The mean age at inclusion was 58.9±12.5 yrs. 264 patients were available for follow-up. Any of the studied cardiovascular events were registered in 79 (29.9%) pts. During the follow-up period, 46 (17.4%) pts died; 35 of 46 (76.1%) pts died because of CVD; 11 (23.9%) pts died due to other causes. Non-fatal cardiovascular events were registered in 44 (16.7%) pts.

The risk of cardiovascular events was higher for ps aged >65 years (OR 5.97, 95% CI 3.33-10.71), serum cholesterol level ≥5.1 mmol/l (OR 1.95, 95% CI 1.04-3.65]), GFR <60 ml/min/1.73 m2 (OR 2.78, 95% CI 1.32-5.56]), history of CVD (OR 2.32, 95% CI 1.22-4.44) Colchicine therapy was associated with the lower risk of cardiovascular events (OR 0.20, 95% CI 0.11-0.39]). Therapy with methorexate and hydroxychloroquine did not exert an influence on opportunity of CVO.

Conclusion

Adverse CVD outcomes in CPPD pts are associated with age, hypercholesterolemia, CKD, and a history of CVD. The intake of colchicine, but not methotrexate and hydroxychloroquine, by patients with CPPD is associated with decline of risk of cardiovascular events.

References

[1]Bashir M, Sherman KA, Solomon DH, et al. Cardiovascular disease risk in calcium pyrophosphate deposition disease: A nationwide study of veterans. Arthritis Care Res (Hoboken). 2021 Sep 14. doi: 10.1002/acr.24783.

Disclosure of Interests

Elena Cheremushkina: None declared, Maxim Eliseev Speakers bureau: Berlin Chemie Menarini Group, Sobi, EGIS, CSC, MosFarma, Alium Group, Olga Sheliabina Speakers bureau: Berlin Chemie Menarini Group, Aleksandra Novikova: None declared, Svetlana Glukhova: None declared

AB1046 EFFICACY OF FEBUXOSTAT IN PATIENTS WITH GOUT STRATIFIED BY BASELINE RENAL FUNCTION

Background

The opportunity of achievement of the target serum UA (sUA) level in pts with gout, stratified by renal function, is not studied.

Objectives

To compare the probability of the sUA level achievement during therapy with febuxostat in patients with gout, stratified according to renal function.

Methods

The prospective study included 136 pts aged ≥18 years with a crystal-verified diagnosis of gout and sUA level >360 µmol/L who had never taken febuxostat or other urate-lowering drugs (at least 2 weeks before the start of the study). All pts were prescribed febuxostat 80 mg/day; if the target sUA level (<360 µmol/l) was not achieved, the dose was increased to 120 mg/day. Prophylactic anti-inflammatory drugs (AIDs) were taken: colchicine in 59 (43.4%) pts, NSAIDs - 51 (37.58%) pts, GC - 12 (98.8%) pts. 14 (10.3%) pts did not take AIDs. Laboratory tests (serum levels of glucose, creatinine, UA) before and after 26 weeks of therapy were collected. GFR was calculated using CKD-EPI formula before and after therapy. The pts were initially divided into groups depending on the CKD stages according to the level of GFR (CKD-EPI): C1 – normal or high renal function (>90 ml/min/1.73 m2), C2 – mildly decreased (60-89 ml/min/1.73 m2), C3 - moderately decreased (30-59 ml/min/1.73 m2), C4 – severely decreased (15-29 ml/min/1.73 m2). The observation period covered at least 26 weeks, the primary end point was the achievement of the target sUA level. The dynamics of GFR was also assessed. Statistica 12.0 package was used for statistical data processing.

Results

It was found that 30 (22.12%) pts had CKD stage 0-1, 28 (66-20.6%) pts - C2, 62 (45.6%) pts – C3, 16 (11.8%) – C4. 98 (72.1%) pts received febuxostat 80 mg/day, 38 (27.9%) pts - 120 mg/day. Pts with CKD C4 were older than ones with CKD C2 (p=0.00001) and CKD C0-1 (p=0.002); had a longer duration of gout (p=0.003); they were more likely to have subcutaneous tophi than pts with CKD C2 (p=0.007). The frequency of diagnosing DM, hypertension, as well as the sUA level in the groups did not differ. The levels of sUA, GFR in patients with gout, stratified by the level of GFR at baseline and after 26 weeks of febuxostat therapy, are given below (Table 1).

Table 1.

Levels of UA, eGFR in patients with gout, stratified by the level of eGFR at baseline and after 26 weeks of febuxostat therapy.

ParametersAll patients, n=136CKD С0-1, n=30CKD С2, n=28CKD С3, n=62CKD С4, n=16UA baseline, µmol/l472,4±99,3451,9±102,8486,9±103,8476,9±86,7468,3±109,8UA after 26 weeks, µmol/l306,27±104,4298,6±104,8*282,2±95,8*318,9±97,6*313,5±106,9*Δ UA, µmol/l166±10,2153,3±10,7204,7±12,4157,9±17,8154,8±14,9UA<360 µmol/l, n (%)117 (84)25 (83)25 (89)51 (82)13 (81)GFR baseline, ml/min/1.73 m263,98±15,3101,3±18,175,9±9,750,2±5,526,5±2,6GFR after 26 weeks, ml/min/1.73 m264,74±26,9102,8±28,6*76,7±9,350,9±6,927,3±4,9

* - p<0.05 between baseline and 26 weeks

The target sUA level was achieved in 33 (87%) patients with DM (the probability did not depend on the initial GFR value). Achievement of target sUA level was registered in 84% of general sample: in 83% of pts with CKD C0-1, 89% - CKD C2, 82% - CKD C3, 81% of pts with CKD C4. Mean GFR values increased in all groups, but significant differences registered in patients with CKD C0-1 (p=0.002) only.

Conclusion

The ability to achieve the target sUA level while taking febuxostat in patients with gout does not depend on renal function, exceeding 80% in patients with CKD C4. The drug is well tolerated regardless of renal function.

Disclosure of Interests

Maxim Eliseev Speakers bureau: Berlin Chemie Menarini Group, Sobi, EGIS, CSC, MosFarma, Alium Group, Olga Sheliabina Speakers bureau: Berlin Chemie Menarini Group, Maria Chikina: None declared

AB1044 RISK FACTORS OF DIABETES MELLITUS IN PATIENTS WITH GOUT (RESULTS OF A PROSPECTIVE STUDY)

Background

It is assumed that the risk of developing diabetes mellitus (DM) is due not only to generally accepted risk factors (RF), but also to RF related to gout.

Objectives

To evaluate the influence of various RF for DM in pts with gout.

Methods

444 pts aged ≥18 years with a crystal-verified diagnosis of gout without DM were included in the study. The average duration of observation was 5.66 [2.69; 7.4] yrs. To identify the RF associated with developing of DM in patients with gout, multivariate logistic regression was used. There were included: gender; DM in relatives; insufficient physical activity; unbalanced diet; age ≥45 yrs; ≥ 4 exacerbation of arthritis per yr; presence of tophi; BMI ≥ 30 kg/m2; presence of hypertension; allopurinol, febuxostat, GC, diuretics, metformin or colchicine intake; GFR <60 ml/min/1.73 m2; serum uric acid (sUA) level ≥420 µmol/l; UA ≥480 µmol/l. Statistica 12.0 package was used for statistical data processing.

Results

DM was developed in 108 (24.3%) pts. Pts who developed DM were older than those who did not develop (52.84±10.96 vs 49.72±11.95 respectively, p=0.02); they were more likely to have heredity for DM of the first and second kinship lines (49.1% vs 25.6% respectively, p=0.0001); they took antihypertensive drugs more often (73.1% vs 50.5%, p=0.0001), also diuretics (27.7% vs 14.8%, p =0.003) and GC (47.2% vs 36.4%, p=0.047). There were more pts with subcutaneous tophi (59.3% vs 29.9%, p=0.001), those who had ≥ 4 attacks of arthritis per yr (67.6% vs 31.6%, p=0.001), sUA ≥480 µmol/l (71.3% vs 50.8%, p=0.0002), sUA≥600 µmol/l (34.3% vs 11.8%, p=0.0002).

According to a multivariable logistic regression, the risk of DM is increased in case of: ≥ 4 arthritis attacks per yr (odds ratio [OR] 5.231, 95% confidence interval [CI] 2.978-9.187, p=0.0001); presence of subcutaneous tophi (OR 2.609, 95% CI 1.500-4.537, p=0.001); sUA level ≥480 µmol/l (OR 2.261, 95% CI 1.022-5.004, p=0.144); hypertension (OR 2.577, 95% CI 1.348-4.926, p=0.004); taking diuretics (OR 2.353, 95% CI 1.193-4.64, p=0.014). The risk of developing DM was reduced by taking febuxostat (OR 0.309, 95% CI 0.113-0.844, p=0.022) and metformin (OR 0.49 (95% CI 0.21; 1.16), p=0.107).

Conclusion

The risk of developing DM in pts with gout is associated with the frequency of arthritis attacks, sUA level ≥480 µmol/l, hypertension and diuretics intake. Therapy with febuxostat or metformin is associated with descended risk of DM.

Disclosure of Interests

Olga Sheliabina Speakers bureau: Berlin Chemie Menarini Group, Maxim Eliseev Speakers bureau: Berlin Chemie Menarini Group, Sobi, EGIS, CSC, MosFarma, Alium Group, Svetlana Glukhova: None declared

Flare Rate Thresholds for Patient Assessment of Disease Activity States in Gout

OBJECTIVE

To determine the relationship between gout flare rate and self-categorization into remission, low disease activity (LDA), and patient acceptable symptom state (PASS).

METHODS

Patients with gout self-categorized as remission, LDA, and PASS, and reported number of flares over the preceding 6 and 12 months. Multinomial logistic regression was used to determine the association between being in each disease state (LDA and PASS were combined) and flare count, and self-reported current flare. A distribution-based approach and extended Youden index identified possible flare count thresholds for each state.

RESULTS

Investigators from 17 countries recruited 512 participants. Remission was associated with a median recalled flare count of zero over both 6 and 12 months. Each recalled flare reduced the likelihood of self-perceived remission compared with being in higher disease activity than LDA/PASS, by 52% for 6 months and 23% for 12 months, and the likelihood of self-perceived LDA/PASS by 15% and 5% for 6 and 12 months, respectively. A threshold of 0 flares in preceding 6 and 12 months was associated with correct classification of self-perceived remission in 58% and 56% of cases, respectively.

CONCLUSION

Flares are significantly associated with perceptions of disease activity in gout, and no flares over the prior 6 or 12 months is necessary for most people to self-categorize as being in remission. However, recalled flare counts alone do not correctly classify all patients into self-categorized disease activity states, suggesting that other factors may also contribute to self-perceived gout disease activity.

Performance of Ultrasound in the Diagnosis of Gout in a Multicenter Study: Comparison With Monosodium Urate Monohydrate Crystal Analysis as the Gold Standard

OBJECTIVE

To examine the performance of ultrasound (US) for the diagnosis of gout using the presence of monosodium urate monohydrate (MSU) crystals as the gold standard.

METHODS

We analyzed data from the Study for Updated Gout Classification Criteria (SUGAR), a large, multicenter observational cross-sectional study of consecutive subjects with at least 1 swollen joint who conceivably may have gout. All subjects underwent arthrocentesis; cases were subjects with confirmed MSU crystals. Rheumatologists or radiologists who were blinded with regard to the results of the MSU crystal analysis performed US on 1 or more clinically affected joints. US findings of interest were double contour sign, tophus, and snowstorm appearance. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Multivariable logistic regression models were used to examine factors associated with positive US results among subjects with gout.

RESULTS

US was performed in 824 subjects (416 cases and 408 controls). The sensitivity, specificity, PPV, and NPV for the presence of any 1 of the features were 76.9%, 84.3%, 83.3%, and 78.2%, respectively. Sensitivity was higher among subjects with a disease duration of ≥2 years and among subjects with subcutaneous nodules on examination (suspected tophus). Associations with a positive US finding included suspected clinical tophus (odds ratio [OR] 4.77 [95% confidence interval (95% CI) 2.23-10.21]), any abnormality on plain radiography (OR 4.68 [95% CI 2.68-8.17]), and serum urate level (OR 1.31 [95% CI 1.06-1.62]).

CONCLUSION

US features of MSU crystal deposition had high specificity and high PPV but more limited sensitivity for early gout. The specificity remained high in subjects with early disease and without clinical signs of tophi.

Survey Definitions of Gout for Epidemiologic Studies: Comparison With Crystal Identification as the Gold Standard

OBJECTIVE

To identify the best-performing survey definition of gout from items commonly available in epidemiologic studies.

METHODS

Survey definitions of gout were identified from 34 epidemiologic studies contributing to the Global Urate Genetics Consortium (GUGC) genome-wide association study. Data from the Study for Updated Gout Classification Criteria (SUGAR) were randomly divided into development and test data sets. A data-driven case definition was formed using logistic regression in the development data set. This definition, along with definitions used in GUGC studies and the 2015 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) gout classification criteria were applied to the test data set, using monosodium urate crystal identification as the gold standard.

RESULTS

For all tested GUGC definitions, the simple definition of "self-report of gout or urate-lowering therapy use" had the best test performance characteristics (sensitivity 82%, specificity 72%). The simple definition had similar performance to a SUGAR data-driven case definition with 5 weighted items: self-report, self-report of doctor diagnosis, colchicine use, urate-lowering therapy use, and hyperuricemia (sensitivity 87%, specificity 70%). Both of these definitions performed better than the 1977 American Rheumatism Association survey criteria (sensitivity 82%, specificity 67%). Of all tested definitions, the 2015 ACR/EULAR criteria had the best performance (sensitivity 92%, specificity 89%).

CONCLUSION

A simple definition of "self-report of gout or urate-lowering therapy use" has the best test performance characteristics of existing definitions that use routinely available data. A more complex combination of features is more sensitive, but still lacks good specificity. If a more accurate case definition is required for a particular study, the 2015 ACR/EULAR gout classification criteria should be considered.

Study for Updated Gout Classification Criteria: Identification of Features to Classify Gout

OBJECTIVE

To determine which clinical, laboratory, and imaging features most accurately distinguished gout from non-gout.

METHODS

We performed a cross-sectional study of consecutive rheumatology clinic patients with ≥1 swollen joint or subcutaneous tophus. Gout was defined by synovial fluid or tophus aspirate microscopy by certified examiners in all patients. The sample was randomly divided into a model development (two-thirds) and test sample (one-third). Univariate and multivariate association between clinical features and monosodium urate-defined gout was determined using logistic regression modeling. Shrinkage of regression weights was performed to prevent overfitting of the final model. Latent class analysis was conducted to identify patterns of joint involvement.

RESULTS

In total, 983 patients were included. Gout was present in 509 (52%). In the development sample (n = 653), the following features were selected for the final model: joint erythema (multivariate odds ratio [OR] 2.13), difficulty walking (multivariate OR 7.34), time to maximal pain <24 hours (multivariate OR 1.32), resolution by 2 weeks (multivariate OR 3.58), tophus (multivariate OR 7.29), first metatarsophalangeal (MTP1) joint ever involved (multivariate OR 2.30), location of currently tender joints in other foot/ankle (multivariate OR 2.28) or MTP1 joint (multivariate OR 2.82), serum urate level >6 mg/dl (0.36 mmoles/liter; multivariate OR 3.35), ultrasound double contour sign (multivariate OR 7.23), and radiograph erosion or cyst (multivariate OR 2.49). The final model performed adequately in the test set, with no evidence of misfit, high discrimination, and predictive ability. MTP1 joint involvement was the most common joint pattern (39.4%) in gout cases.

CONCLUSION

Ten key discriminating features have been identified for further evaluation for new gout classification criteria. Ultrasound findings and degree of uricemia add discriminating value, and will significantly contribute to more accurate classification criteria.

Diagnostic Arthrocentesis for Suspicion of Gout Is Safe and Well Tolerated

OBJECTIVE

To determine the frequency of adverse events of diagnostic arthrocentesis in patients with possible gout.

METHODS

Consecutive patients underwent arthrocentesis and were evaluated at 6 weeks to determine adverse events. The 95% CI were obtained by bootstrapping.

RESULTS

Arthrocentesis was performed in 910 patients, and 887 (97.5%) were evaluated for adverse events. Any adverse event was observed in 12 participants (1.4%, 95% CI 0.6-2.1). There was 1 case (0.1%, 95% CI 0-0.34) of septic arthritis.

CONCLUSIONS

Diagnostic arthrocentesis is associated with a low frequency of adverse events. Septic arthritis rarely occurs.

Performance of classification criteria for gout in early and established disease

OBJECTIVES

To compare the sensitivity and specificity of different classification criteria for gout in early and established disease.

METHODS

This was a cross-sectional study of consecutive rheumatology clinic patients with joint swelling in which gout was defined by presence or absence of monosodium urate crystals as observed by a certified examiner at presentation. Early disease was defined as patient-reported onset of symptoms of 2 years or less.

RESULTS

Data from 983 patients were collected and gout was present in 509 (52%). Early disease was present in 144 gout cases and 228 non-cases. Sensitivity across criteria was better in established disease (95.3% vs 84.1%, p<0.001) and specificity was better in early disease (79.9% vs 52.5%, p<0.001). The overall best performing clinical criteria were the Rome criteria with sensitivity/specificity in early and established disease of 60.3%/84.4% and 86.4%/63.6%. Criteria not requiring synovial fluid analysis had sensitivity and specificity of less than 80% in early and established disease.

CONCLUSIONS

Existing classification criteria for gout have sensitivity of over 80% in early and established disease but currently available criteria that do not require synovial fluid analysis have inadequate specificity especially later in the disease. Classification criteria for gout with better specificity are required, although the findings should be cautiously applied to non-rheumatology clinic populations.