A prediction rule for polyarticular extension in oligoarticular-onset juvenile idiopathic arthritis.

OBJECTIVES: To search for predictors of polyarticular extension in children with oligoarticular-onset juvenile idiopathic arthritis (JIA) and to develop a prediction model for an extended course. METHODS: The clinical charts of consecutive patients with oligoarticular-onset JIA and ≥2 years of disease duration were reviewed. Predictor variables included demographic data, number and type of affected joints, presence of iridocyclitis, laboratory tests including antinuclear antibodies, and therapeutic interventions in the first 6 months. Joint examinations were evaluated to establish whether after the first 6 months of disease patients had persistent or extended course (i.e. involvement of 4 or less, or 5 or more joints). Statistics included univariable and multivariable analyses. Regression coefficients (ß) of variables that entered the best-fitting logistic regression model were converted and summed to obtain a "prediction score" for an extended course. RESULTS: A total of 480 patients with a median disease duration of 7.4 years were included. 61.2% had persistent oligoarthritis, whereas 38.8% experienced polyarticular extension. On multivariable analysis, independent correlations with extended course were identified for the presence of ≥2 involved joints and a CRP >0.8 mg/dl in the first 6 months. The prediction score ranged from 0 to 6 and its cut-off that discriminated best between patients who had or did not have polyarticular extension was >1. Sensitivity and specificity were 59.6 and 79.8, respectively. CONCLUSIONS: The number of affected joints and the CRP level in the first 6 months were the strongest predictors of polyarticular extension in our children with oligoarticular-onset JIA.

Analysis of arthritis flares after achievement of inactive disease with methotrexate monotherapy in juvenile idiopathic arthritis.

OBJECTIVES: To investigate the frequency of arthritis flare and factors affecting occurrence of flare in children with juvenile idiopathic arthritis (JIA) who achieved inactive disease (ID) with methotrexate (MTX) monotherapy. METHODS: A total of 217 patients were included. The modality of treatment discontinuation, time of MTX withdrawal, and disease course were examined retrospectively. For each patient, the first episode of ID after MTX start was evaluated. Patient follow-up was censored at occurrence of flare or at last visit with persistent ID. RESULTS: 170 patients (78.3%) had arthritis flare after a median of 1.6 years, whereas 47 (21.7%) maintained ID until last visit, after a median of 3 years. 54.2% of patients had discontinued MTX after ID, whereas 45.8% were still receiving MTX at the time of study censoring. Among patients who had MTX withdrawn, the median interval between ID and MTX stop was 1.5 years. Occurrence of flare was more common in patients who were still receiving MTX at study censoring than in those who had discontinued MTX (p<0.001). Most patients (78.8%) had MTX tapered over time by increasing the interval between doses. Tapering modality was comparable between patients with flare and persistent ID. Only 7.7% of the patients had a biologic DMARD started at the time of flare. CONCLUSIONS: Our results confirm that children with JIA who achieve ID with MTX monotherapy have a high risk of arthritis flare. The risk of flare was independent of withdrawal strategy. Most flare episodes were not treated with biologic therapy.

Antinuclear antibody-positive patients should be grouped as a separate category in the classification of juvenile idiopathic arthritis.

OBJECTIVE: We undertook this study to test the hypothesis that in the International League of Associations for Rheumatology (ILAR) classification of juvenile idiopathic arthritis (JIA), patients with similar characteristics can be classified into different categories. We sought to investigate whether antinuclear antibody (ANA)-positive patients having disease in the ILAR categories of oligoarthritis, rheumatoid factor-negative polyarthritis, psoriatic arthritis, and undifferentiated arthritis share homogeneous features and to compare these features with those of ANA-negative patients having the same categories of disease. METHODS: We identified JIA patients who had been followed up during a 22-year period. ANA positivity was defined as ≥2 positive results at a titer of ≥1:160. Demographic and clinical features were recorded retrospectively and compared between ANA-positive and ANA-negative patients. RESULTS: Of a total of 971 patients, 711 were ANA positive, 149 were ANA negative, and 111 had an indeterminate ANA status. Patients with indeterminate ANA status were excluded. ANA-positive patients in the different ILAR categories were similar in terms of age at disease presentation, female-to-male ratio, and frequency of asymmetric arthritis and iridocyclitis. Compared with ANA-positive patients, the ANA-negative group was older at disease presentation and had a lower prevalence of females, a lower frequency of iridocyclitis and asymmetric arthritis, a greater number of affected joints over time, and a different pattern of arthritis. The close relationship between the presence of ANAs and younger age at disease presentation, female predominance, asymmetric arthritis, development of iridocyclitis, lower number of affected joints over time, and lack of hip involvement was also confirmed by multivariate and multiple correspondence analysis. CONCLUSION: Our findings substantiate the hypothesis that ANA-positive patients classified into different JIA categories by current ILAR criteria constitute a homogeneous patient population.

A prediction rule for lack of achievement of inactive disease with methotrexate as the sole disease-modifying antirheumatic therapy in juvenile idiopathic arthritis.

BACKGROUND: To investigate the frequency of achievement of inactive disease (ID) in children with juvenile idiopathic arthritis (JIA) treated with methotrexate (MTX) as the sole disease-modifyng antirheumatic (DMARD) therapy and to develop a prediction model for lack of attainment of ID. METHODS: The clinical charts of consecutive patients started with MTX as the sole DMARD between 2000 and 2013 were reviewed. Patient follow-up was censored at first episode of ID or, in case ID was not reached, at last follow-up visit or when a biologic DMARD was prescribed. The characteristic at MTX start of patients who achieved or did not achieve ID were compared with univariate and multivariable analyses. Regression coefficients (ß) of variables that entered the best-fitting logistic regression model were converted and summed to obtain a "prediction score" for lack of achievement of ID. RESULTS: A total of 375 patients were included in the study. During MTX administration, 8.8% were given systemic corticosteroids and 44.1% intra-articular corticosteroids. After MTX start, 229 (61%) patients achieved ID after a median of 1.7 years, whereas 146 patients (39%) did not reach ID after a median of 1.2 years. On multivariable analysis, independent correlations with lack of achievement of ID were identified for the disease categories of systemic arthritis, enthesitis-related arthritis (ERA) and polyarthritis and C-reactive protein (CRP) >  1.4 mg/dl. The prediction score ranged from 0 to 3 and its cutoff that discriminated best between patients who achieved or did not achieve ID was > 0.5. The categories of systemic arthritis or ERA, both of which had a score greater than 0.5, were sufficient alone to predict a lower likelihood to reach ID. Polyarthritis and increased CRP, whose score was 0.5, assumed a predictive value only when present in association. CONCLUSION: A conventional treatment regimen based on MTX as the sole DMARD led to achievement of ID in a sizeable proportion of children with JIA. Our findings help to outline the characteristics of patients who may deserve a synthetic DMARD other than MTX or the introduction of a biologic DMARD from disease outset.

Development and Testing of a Hybrid Measure of Muscle Strength in Juvenile Dermatomyositis for Use in Routine Care.

OBJECTIVE: To develop and test a hybrid measure of muscle strength for juvenile dermatomyositis (JDM), which is based on the combination of the Manual Muscle Testing in 8 muscles (MMT-8) and the Childhood Myositis Assessment Scale (CMAS) but is more comprehensive than the former and more feasible than the latter. METHODS: The hybrid MMT-8/CMAS (hMC) is composed of all 8 items of the MMT-8 and 3 items of the CMAS: time of head lift, assessment of abdominal muscles, and floor rise. The score ranges 0-100, with 100 indicating normal muscle strength. Validation procedures were conducted using 3 large multinational patient samples, including a total of 810 JDM patients. RESULTS: The hMC revealed face and content validity, good construct validity, excellent test-retest reliability (intraclass correlation coefficient = 0.99), and internal consistency (Cronbach's α = 0.94), strong responsiveness to clinical change over time (standardized response mean = 0.8 among patients judged as improved by the caring physician), and satisfactory capacity to discriminate patients judged as being in the states of inactive disease or low, moderate, or high disease activity by the physician (P < 0.001) or patients whose parents were satisfied or not satisfied with the illness course (P < 0.001). CONCLUSION: The hMC was found to possess good measurement properties in a large population of patients with a wide range of disease activity and severity. The new tool, which is primarily intended for use in routine clinical care, should be further tested in other populations of patients evaluated prospectively.

A new approach to clinical care of juvenile idiopathic arthritis: the Juvenile Arthritis Multidimensional Assessment Report.

OBJECTIVE: To develop and test a new multidimensional questionnaire for assessment of children with juvenile idiopathic arthritis (JIA) in standard clinical care. METHODS: The Juvenile Arthritis Multidimensional Assessment Report (JAMAR) includes 15 parent or patient-centered measures or items that assess well-being, pain, functional status, health-related quality of life, morning stiffness, disease activity, disease status and course, joint disease, extraarticular symptoms, side effects of medications, therapeutic compliance, and satisfaction with illness outcome. The JAMAR is proposed for use as both a proxy-report and a patient self-report, with the suggested age range of 7-18 years for use as a self-report. From March 2007 to September 2009, the questionnaire was completed by the parents of 618 children with JIA in 1814 visits and by 332 children in 749 visits. RESULTS: The JAMAR was found to be feasible and to possess face and content validity. All parents and children reported that the questionnaire was simple and easy to understand. Completion and scoring appeared to be quick, requiring < 15 minutes. There were very few missing data. Parents' proxy-reported and children's self-reported data were remarkably concordant. The JAMAR provided thorough information for the study patients about recent medical history and current health status. It performed similarly across different children's ages and characterized the level of disease activity and disability well. CONCLUSION: The development of the JAMAR introduces a new approach in pediatric rheumatology practice. This new questionnaire may help enhance the quality of care of children with JIA.