Differences between early vs. late-onset of psoriatic arthritis: Data from the RESPONDIA and REGISPONSER registries

OBJECTIVES

The objective was to evaluate the association between the age at onset of psoriatic arthritis (PsA) symptoms with the characteristics and burden of the disease.

METHODS

This was an observational and cross-sectional study that included a subgroup of 231 patients with PsA with < 10 years of disease duration from the REGISPONSER and RESPONDIA registries. Patients were divided into two groups according to the age of PsA symptom onset (early onset: ≤ 40-years-old and late onset: ≥ 60-years-old). The characteristics and burden of the disease were compared between the two groups, and multivariate logistic regression was performed to determine the factors independently associated with late-onset PsA.

RESULTS

Patients from the early-onset group showed a significantly lower prevalence of males [94 (62.3%) vs. 38 (86.4%)] and a higher prevalence of enthesitis [44 (24.6%) vs. 5 (9.8%)] and sacroiliitis [30 (16.8%) vs. 4 (7.7%)]. Additionally, the early-onset group showed lower scores on the BASFI [2.2 (2.2) vs. 3.3 (2.5)] and minor structural damage (BASRI) in both the spine [1.6 (2) vs. 2.9 (3)] and whole axial skeleton (total BASRI) [1.9 (2.4) vs. 3.4 (3.4)]. In contrast, no statistically significant differences were found between the groups in disease activity evaluated by the BASDAI and ASDAS. Logistic regression analysis showed that late-onset PsA was independently associated with being male (OR 4.4, 95% CI: 1.3, 16.3), greater structural damage (total BASRI) (OR 3.3, 95% CI: 1.3, 8.1), a higher frequency of arthritis in the upper limbs (OR 2.8, 95% CI: 1, 7.7), and greater loss of function (BASFI) (OR 1.3, 95% CI: 1, 1.6).

CONCLUSIONS

Patients with late-onset PsA showed different clinical characteristics and greater disease severity than those with early-onset PsA.

Synovial fluid analysis for the enhanced clinical diagnosis of crystal arthropathies in a tertiary care institution

INTRODUCTION/OBJECTIVES

Few studies have addressed the detection and clinical impact of different crystals in patients with diverse rheumatologic diagnoses in Latin America. The aim of this study was to assess the consistency between the clinical referring diagnosis and the identification of crystals, such as monosodium urate (MSU) and calcium pyrophosphate (CPP), in the synovial fluid (SF) of patients from a Mexican tertiary care institution.

METHODS

We reviewed the results of 264 SF analyses to identify any changes in diagnosis upon SF analysis. We reported patient medical file data on sex, age, diagnosis, and microscopic SF analysis results. We performed consistency analyses between referring diagnoses and SF findings with McNemar's test.

RESULTS

The prevalence of MSU crystals in SF was noted in 89.1% of gout cases and 9.09% of cases of calcium pyrophosphate disease (CPPD). CPP crystals were present in 54.5% of CPPD cases, 42.9% of osteoarthritis (OA) cases, and 7.27% of gout cases. Calcium hydroxyapatite (HA) crystals were identified in 5.45% of gout cases, 33.3% of rheumatoid arthritis (RA) cases, 57.1% of OA cases, and 63.6% of CPPD cases. Cholesterol and lipid crystals were present in small proportions in RA cases. Glucocorticoid crystals were observed in 1.85% of gout cases, 44.4% of RA cases, and 42.9% of OA cases. We observed an association of MSU identification with clinical suspicion of gout (P = 0.08), CPP with OA (P = 0.26) and CPPD (P = 0.50). An association was noted between HA and the diagnosis of CPPD (P = 0.84) and OA (P > 0.99). The number of initial diagnoses that changed upon SF analysis was 14.3%.

CONCLUSIONS

SF analysis has major diagnostic value regarding MSU crystals and gout. Our findings underscore the importance of SF crystal analysis in identifying the prevalence of crystals in the Mexican population. SF analysis provides for better diagnosis of crystal arthropathies and improves the quality of the medical care that the patient receives. Key Points • Synovial fluid analysis in laboratories from developing countries has been scarce. • In some cases, the initial diagnosis is modified after of synovial fluid analysis. • This study confirmed that synovial fluid analysis exhibits major diagnostic value for urate crystals and gout.

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.

How to calculate the ASDAS based on C-reactive protein without individual questions from the BASDAI: the BASDAI-based ASDAS formula

OBJECTIVES

To develop a new equation to calculate the Ankylosing Spondylitis Disease Activity Score based on CRP (ASDAS-CRP) using only the BASDAI total score and CRP.

METHODS

Axial SpA (axSpA) patients from the Cordoba Spondyloarthritis Registry cohort were recruited as a derivation cohort, while a retrospective sample from the Spanish Rheumatology Society National Registry of Spondyloarthropathies and Ibero American Spondyloarhtritis Registry registers was used as a validation cohort. We built a new equation based only on the BASDAI and CRP, defining a new formula: the BASDAI-based ASDAS (BASDAS). Linear regression analysis was used to determine the coefficients of the equation in the derivation cohort and it was subsequently validated in the validation cohort.

RESULTS

A total of 52 axSpA patients in the derivation cohort and 3359 patients in the validation cohort were included. In the derivation cohort, the mean BASDAS [2.24 (s.d. 0.90)] was very similar to the ASDAS-CRP [2.23 (s.d. 0.95)], with a very strong correlation (r = 0.96, P < 0.001). In the validation cohort, the mean BASDAS was 3.31 (s.d. 1.37) and the ASDAS-CRP was 3.19 (s.d. 1.27), which also had a very strong correlation (r = 0.95, P < 0.001). Intraclass correlation coefficients were excellent in both cohorts (0.963 and 0.947, respectively).

CONCLUSION

The BASDAS performs similarly to the ASDAS-CRP and can be calculated with only the BASDAI total score and CRP, allowing evaluation of disease activity in retrospective studies where the individual items of the BASDAI are not available.

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.

Development of Preliminary Remission Criteria for Gout Using Delphi and 1000Minds Consensus Exercises

OBJECTIVE

To establish consensus for potential remission criteria to use in clinical trials of gout.

METHODS

Experts (n = 88) in gout from multiple countries were invited to participate in a web-based questionnaire study. Three rounds of Delphi consensus exercises were conducted using SurveyMonkey, followed by a discrete-choice experiment using 1000Minds software. The exercises focused on identifying domains, definitions for each domain, and the timeframe over which remission should be defined.

RESULTS

There were 49 respondents (56% response) to the initial survey, with subsequent response rates ranging from 57% to 90%. Consensus was reached for the inclusion of serum urate (98% agreement), flares (96%), tophi (92%), pain (83%), and patient global assessment of disease activity (93%) as measurement domains in remission criteria. Consensus was also reached for domain definitions, including serum urate (<0.36 mm), pain (<2 on a 10-point scale), and patient global assessment (<2 on a 10-point scale), all of which should be measured at least twice over a set time interval. Consensus was not achieved in the Delphi exercise for the timeframe for remission, with equal responses for 6 months (51%) and 1 year (49%). In the discrete-choice experiment, there was a preference towards 12 months as a timeframe for remission.

CONCLUSION

These consensus exercises have identified domains and provisional definitions for gout remission criteria. Based on the results of these exercises, preliminary remission criteria are proposed with domains of serum urate, acute flares, tophus, pain, and patient global assessment. These preliminary criteria now require testing in clinical data sets.

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.

Gender differences among patients with primary ankylosing spondylitis and spondylitis associated with psoriasis and inflammatory bowel disease in an iberoamerican spondyloarthritis cohort

The aim of the study was to compare clinical manifestations, disease activity, functional capacity, spinal mobility, and radiological findings between men and women from a multicenter, multiethnic Ibero-American cohort of patients with Spondyloarthritis (SpA).This observational cross-section study included 1264 consecutive SpA patients who fulfilled the modified New York criteria for ankylosing spondylitis (AS). Demographic, clinical, and radiologic data were evaluated. Categorical data were compared by X or Fisher's exact tests and continuous variables by ANOVA with post-hoc tests.Primary AS was diagnosed in 1072 patients, psoriatic spondylitis in 147, and spondylitis associated to inflammatory bowel disease (IBD) in 45 patients. Overall, male patients were significantly younger, had longer diagnostic delay, lower disease activity, worse spinal mobility, better quality of life, and more severe radiologic damage. Dactylitis and enthesitis, as well as swollen joint count, were significantly more common among women. In primary AS, there was a marked male predominance (76.2%). Among patients with psoriatic spondylitis, male predominance was lower (57.8%), but was also associated with worse spinal mobility and more severe radiologic damage. In the total population, male patients with primary AS referred higher permanent work disability (13.2% vs 6.9%; P < 0.05), although no difference was observed in psoriatic or IBD spondylitis according to the gender.Among Ibero-American SpA patients, there are some differences in clinical and radiological manifestations, men showing more structural damage, whereas women more active disease. These data suggest that the phenotype of SpA differs between genders. This can influence the subsequent diagnostic approach and therapeutic decisions.

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.

Tophus burden reduction with pegloticase: results from phase 3 randomized trials and open-label extension in patients with chronic gout refractory to conventional therapy

INTRODUCTION

Two replicate randomized, placebo-controlled six-month trials (RCTs) and an open-label treatment extension (OLE) comprised the pegloticase development program in patients with gout refractory to conventional therapy. In the RCTs, approximately 40% of patients treated with the approved dose saw complete response (CR) of at least one tophus. Here we describe the temporal course of tophus resolution, total tophus burden in patients with multiple tophi, tophus size at baseline, and the relationship between tophus response and urate-lowering efficacy.

METHODS

Baseline subcutaneous tophi were analyzed quantitatively using computer-assisted digital images in patients receiving pegloticase (8 mg biweekly or monthly) or placebo in the RCTs, and pegloticase in the OLE. Tophus response, a secondary endpoint in the trials, was evaluated two ways. Overall tophus CR was the proportion of patients achieving a best response of CR (without any new/enlarging tophi) and target tophus complete response (TT-CR) was the proportion of all tophi with CR.

RESULTS

Among 212 patients randomized in the RCTs, 155 (73%) had ≥ 1 tophus and 547 visible tophi were recorded at baseline. Overall tophus CR was recorded in 45% of patients in the biweekly group (P = 0.002 versus placebo), 26% in the monthly group, and 8% in the placebo group after six months of RCT therapy. TT-CR rates at six months were 28%, 19%, and 2% of tophi, respectively. Patients meeting the primary endpoint of sustained urate-lowering response to therapy (responders) were more likely than nonresponders to have an overall tophus CR at six months (54% vs 20%, respectively and 8% with placebo).

CONCLUSIONS

Pegloticase reduced tophus burden in patients with refractory tophaceous gout, especially those achieving sustained urate-lowering. Complete resolution of tophi occurred in some patients by 13 weeks and in others with longer-term therapy.

TRIAL REGISTRATIONS

NCT00325195, NCT01356498.

A delphi exercise to identify characteristic features of gout - opinions from patients and physicians, the first stage in developing new classification criteria

OBJECTIVE

To identify a comprehensive list of features that might discriminate between gout and other rheumatic musculoskeletal conditions, to be used subsequently for a case-control study to develop and test new classification criteria for gout.

METHODS

Two Delphi exercises were conducted using Web-based questionnaires: one with physicians from several countries who had an interest in gout and one with patients from New Zealand who had gout. Physicians rated a list of potentially discriminating features that were identified by literature review and expert opinion, and patients rated a list of features that they generated themselves. Agreement was defined by the RAND/UCLA disagreement index.

RESULTS

Forty-four experienced physicians and 9 patients responded to all iterations. For physicians, 71 items were identified by literature review and 15 more were suggested by physicians. The physician survey showed agreement for 26 discriminatory features and 15 as not discriminatory. The patients identified 46 features of gout, for which there was agreement on 25 items as being discriminatory and 7 items as not discriminatory.

CONCLUSION

Patients and physicians agreed upon several key features of gout. Physicians emphasized objective findings, imaging, and patterns of symptoms, whereas patients emphasized severity, functional results, and idiographic perception of symptoms.

Comparison of the clinical expression of patients with ankylosing spondylitis from Europe and Latin America

OBJECTIVE

To compare the clinical, demographic, and serologic characteristics and the treatment of patients diagnosed with ankylosing spondylitis (AS) from Europe (EU) and Latin America (LA).

METHODS

We included 3439 patients from national registries: the Spanish Registry of Spondyloarthritis (REGISPONSER), the Belgian registry (ASPECT), and the Latin American Registry of Spondyloarthropathies (RESPONDIA). We selected patients with diagnosis of AS who met the modified New York classification criteria. Demographic, clinical, disease activity, functional, and metrological measurement data were recorded. Current treatment was recorded. The population was classified into 2 groups: patients with disease duration < 10 years and those with disease duration ≥ 10 years. A descriptive and comparative analysis of variables of both groups was carried out.

RESULTS

There were 2356 patients in EU group and 1083 in LA group. Prevalence of HLA-B27 was 71% in LA group and 83% in EU group (p < 0.001). We found a greater frequency of peripheral arthritis and enthesitis (p < 0.001) in the LA population; prevalence of arthritis was 57% in LA and 42% in EU, and for enthesitis, 54% and 38%. Except for treatment with anti-tumor necrosis factor (anti-TNF), the use of nonsteroidal antiinflammatory drugs (NSAID), corticosteroids, and disease-modifying antirheumatic drugs (DMARD), and the association of anti-TNF and methotrexate use showed a significant difference (p < 0.001) in the 2 populations.

CONCLUSION

The principal differences in the clinical manifestations of patients with AS from EU and LA were the greater frequency of peripheral arthritis and enthesitis in LA group, the higher percentage of HLA-B27 in EU group, and the form of treatment, with a greater use of NSAID, steroids, and DMARD in the LA group.

Differential features between primary ankylosing spondylitis and spondylitis associated with psoriasis and inflammatory bowel disease

OBJECTIVE

To describe differential characteristics of axial involvement in ankylosing spondylitis (AS) as compared with that seen in psoriatic arthritis (PsA) and inflammatory bowel disease (IBD) in a cohort of Ibero-American patients.

METHODS

This study included 2044 consecutive patients with spondyloarthritis (SpA; ESSG criteria). Demographic, clinical, disease activity, functional ability, quality of life, work status, radiologic, and therapeutic data were evaluated and collected by RESPONDIA members from different Ibero-American countries between June and December 2006. Patients selected for analysis met modified New York criteria (mNY) for AS.

RESULTS

A total of 1264 patients met the New York criteria for AS: 1072 had primary AS, 147 had psoriatic, and 45 had IBD-associated spondylitis. Median disease duration was comparable among the 3 patient groups. Patients with primary AS were significantly younger (p = 0.01) and presented a higher frequency of males (p = 0.01) than the other 2 groups. Axial manifestations such as inflammatory back pain and sacroiliac pain were significantly more frequent in patients with primary AS (p = 0.05) versus other groups, whereas frequency of dactylitis, enthesitis, and peripheral arthritis was more common in patients with psoriatic spondylitis (p = 0.05). Spinal mobility was significantly more limited in patients with primary AS versus the other 2 groups (p = 0.0001). Radiologic changes according to BASRI total score were equally significant in primary AS. Disease activity (BASDAI), functional ability (BASFI), and quality of life (ASQoL) scores were comparable in the 3 groups.

CONCLUSION

Patients with primary AS had more severe axial involvement than those with spondylitis associated with psoriasis or IBD. Functional capacity, disease activity, and quality of life were comparable among the groups studied.

A modified Delphi exercise to determine the extent of consensus with OMERACT outcome domains for studies of acute and chronic gout

OBJECTIVES

To reach consensus with recommendations made by an OMERACT Special Interest Group (SIG).

METHODS

Rheumatologists and industry representatives interested in gout rated and clarified, in three iterations, the importance of domains proposed by the OMERACT SIG for use in acute and chronic gout intervention studies. Consensus was defined as a value of less than 1 of the UCLA/RAND disagreement index.

RESULTS

There were 33 respondents (61% response rate); all agreed the initial items were necessary, except "total body urate pool". Additional domains were suggested and clarification sought for defining "joint inflammation" and "musculoskeletal function". Items that demonstrated no clear decision were re-rated in the final iteration. There were six highly rated items (rating 1-2) with four slightly lower rating items (rating 3) for acute gout; and 11 highly rated items with eight slightly lower ratings for chronic gout.

CONCLUSIONS

Consensus is that the following domains be considered mandatory for acute gout studies: pain, joint swelling, joint tenderness, patient global, physician global, functional disability; and for chronic gout studies: serum urate, gout flares, tophus regression, health-related quality of life, functional disability, pain, patient global, physician global, work disability and joint inflammation. Several additional domains were considered discretionary.

Prevalence and risk factors for urolithiasis in primary gout: is a reappraisal needed?

OBJECTIVE

To assess the prevalence and risk factors for urolithiasis in primary gout.

METHODS

One hundred forty patients with primary gout were studied. Urolithiasis was defined as a history of urolithiasis, or nephrolithiasis detected via ultrasonography in patients with no previous record of urolithiasis. Patient age, duration of gout, presence of tophi, obesity, alcoholism, high blood pressure, diabetes, hyperlipidemia, family history of urolithiasis, daily urine output, uricemia, urine pH, FeNa, FeUrate, urine pH/FeUrate index, and daily urine excretion of urate, sodium, calcium and potassium were compared between lithiasic and non-lithiasic subjects.

RESULTS

Fifty-five (39%; 95% CI 31-47) patients had urolithiasis, of which 37 (26%) were diagnosed by clinical history and 18 (13%) by ultrasonography. Patients with a silent kidney stone diagnosed by ultrasound tended to have shorter evolution of gout. Aside from urinary H+ ion concentration (lithiasic subjects 5.17 +/- 3.9 microM/l; non-lithiasic subjects 3.80 +/- 3.01 microM/l; p = 0.02), no difference was found between lithiasic and non-lithiasic subjects for the other variables studied.

CONCLUSION

Ultrasonography increased the probability of diagnosing urolithiasis by 50%, meaning the prevalence of urolithiasis in gout is likely higher than previously reported. A higher urinary H+ ion concentration was the only variable associated with urolithiasis. Due to advances in diagnosis of gout and urolithiasis, as well as biochemical assays, the prevalence and risk factors for urolithiasis in gout require reassessment.

Differences in idiopathic inflammatory myopathy phenotypes and genotypes between Mesoamerican Mestizos and North American Caucasians: ethnogeographic influences in the genetics and clinical expression of myositis

OBJECTIVE

As part of a larger, worldwide study of the ethnogeography of myositis, we evaluated the clinical, serologic, and immunogenetic features of Mestizo (Mexican and Guatemalan) and North American Caucasian patients with idiopathic inflammatory myopathy (IIM).

METHODS

Clinical manifestations, autoantibodies, HLA-DRB1 and DQA1 alleles, and immunoglobulin Gm/Km allotypes were compared between 138 Mestizos with IIM and 287 Caucasians with IIM, using the same classification criteria and standardized questionnaires.

RESULTS

IIM in Mestizo patients was characterized by a higher proportion of dermatomyositis (69% of adult Mestizos versus 35% of adult Caucasians; P < 0.001) and anti-Mi-2 autoantibodies (30% versus 7% of adults, respectively, and 32% versus 4% of children, respectively; P < 0.01). Genetic risk factors also differed in these populations. Whereas Mestizos had no HLA risk factors for IIM, HLA-DRB1*0301, the linked allele DQA1*0501, and DRB1 alleles sharing the first hypervariable region motif (9)EYSTS(13) were major risk factors in Caucasian patients with IIM. Furthermore, different HLA-DRB1 and DQA1 alleles were associated with anti-Mi-2 autoantibodies (DRB1*04 and DQA1*03 in Mestizos and DRB1*07 and DQA1*02 in Caucasians). Immunoglobulin gamma-chain allotypes Gm(1), Gm(17) (odds ratio for both 11.3, P = 0.008), and Gm(21) (odds ratio 7.3, P = 0.005) and kappa-chain allotype Km(3) (odds ratio 7.3, P = 0.005) were risk factors for IIM in Mestizos; however, no Gm or Km allotypes were risk or protective factors in Caucasians. In addition, Gm and Km phenotypes were unique risk factors (Gm 1,3,17 5,13,21 and Gm 1,17 23 21 and Km 3,3) or protective factors (Km 1,1) for the development of myositis and anti-Mi-2 autoantibodies (Gm 1,2,3,17 23 5,13,21) in adult Mestizos.

CONCLUSION

IIM in Mesoamerican Mestizos differs from IIM in North American Caucasians in the frequency of phenotypic features and in the immune-response genes predisposing to and protecting from myositis and anti-Mi-2 autoantibodies at 4 chromosomal loci. These and other data suggest the likelihood that the expression of IIM is modulated by different genes and environmental exposures around the world.

Comparison of two schedules for administering oral low-dose methotrexate (weekly versus every-other-week) in patients with rheumatoid arthritis in remission: a twenty-four week, single blind, randomized study

OBJECTIVE

To compare the efficacy of 2 low-dose oral methotrexate (MTX) schedules in maintaining remission in patients with rheumatoid arthritis (RA).

METHODS

Patients with RA were included if they were receiving treatment with weekly MTX for at least 9 months and the RA was in remission (defined by American College of Rheumatology [ACR] criteria) for at least 6 months. Patients were stratified by treatment and randomly assigned to weekly or every-other-weekly (EOW; reducing their monthly dose by half) treatment with MTX. Patients were evaluated by a rheumatologist (blinded to the treatment schedule) at baseline and at 6, 12, and 24 weeks. The evaluations included joint counts, Ritchie Articular Index, Health Assessment Questionnaire Disability Index, physician's and patient's global health assessments, visual analog scale for pain, and incidence of adverse effects. Laboratory evaluations were done at baseline and at week 24.

RESULTS

Fifty-one patients were included (26 taking weekly MTX, 25 taking EOW MTX). Baseline comparisons showed no differences between the groups. The mean duration of RA was <3 years in both groups, and they had been started on weekly MTX treatment early after diagnosis. After 24 weeks, >90% of the patients in both groups continued in remission. Evaluations of disease activity at 6 and 12 weeks showed no between-group differences. EOW MTX patients who experienced relapse were switched back to weekly MTX, and after a few weeks, their RA was again controlled. The incidence of adverse effects was slightly higher in the weekly MTX group, although the difference did not reach statistical significance. The observed laboratory values were very similar for both groups, except for the serum aspartate aminotransferase and alanine aminotransferase levels, which decreased in the EOW MTX group and were statistically significant at week 24 (P = 0.04 and P = 0.006, respectively).

CONCLUSION

EOW MTX represents a valid therapeutic alternative for a specific subgroup of RA patients, as outlined by the ACR remission criteria. Patients with a short disease duration who were treated early after disease onset with weekly MTX and who achieve sustained remission have a higher probability of success with the EOW MTX schedule.

Immunoregulatory defects in juvenile rheumatoid arthritis. Comparison between patients with the systemic or polyarticular forms

Studies of cellular immunity in juvenile chronic arthritis (juvenile rheumatoid arthritis, JRA) have been scant, controversial, or have not addressed the issue of the different forms of the disease. We studied 23 patients with JRA of either systemic (n = 8) or polyarticular (n = 15) type of onset and compared the findings to those made in 10 healthy children of similar age. Both groups of patients with JRA were found to have increased CD8 T cells, normal production of interleukin-1 and 2 and decreased production of B cell stimulatory factor in their peripheral blood. In addition, patients with systemic JRA were found to have decreased spontaneously expanded and concanavalin-A induced suppressor functions. These findings in both forms of JRA are distinguishable from those that have been made in other connective tissue diseases including the adult form of rheumatoid arthritis.