Differences in the profiles of circulating levels of soluble tumor necrosis factor receptors and interleukin 1 receptor antagonist reflect the heterogeneity of the subgroups of juvenile rheumatoid arthritis

OBJECTIVE: To determine whether levels of soluble tumor necrosis factor receptor 55 (sTNFR55), sTNFR75, and interleukin 1 receptor antagonist (IL-1Ra) can differentiate different subtypes of juvenile rheumatoid arthritis (JRA), and to determine if the levels of these proteins correlate with disease activity. METHODS: Serum sTNFR (55 and 75) and IL-1Ra levels were measured by ELISA in 34 patients with JRA and these values were correlated with disease subtype and activity. RESULTS: Serum sTNFR55 levels were significantly elevated in patients with systemic onset JRA (SoJRA) (mean +/- 2 SD, 2.9 +/- 1.8 ng/ml) (p < or = 0.05) compared to rheumatoid factor positive (RF+) polyarticular JRA (2.1 +/- 0.6), RF-polyarticular JRA (1.5 +/- 0.6), and pauciarticular JRA (1.4 +/- 0.4). There was a trend for elevation of sTNFR75 levels in patients with SoJRA compared to other subtypes (p = 0.08). More patients had elevated levels of sTNFR75 than sTNFR55 (15 vs 7). This was true for all subsets (SoJRA 7 vs 5; polyarticular JRA 4 vs 2; and pauciarticular JRA 4 vs 0). In contrast to sTNFR, IL-1Ra levels were significantly elevated in RF+ polyarticular JRA compared to the other subgroups (p < or = 0.001). We found statistically significant Pearson correlations between (1) sTNFR75 and hemoglobin concentration: and (2) IL-1Ra and number of active joints and number of joints with effusions. CONCLUSION: The increased serum level of sTNF receptors in SoJRA suggests that TNF is likely more important than IL-1 in systemic inflammation and in particular in SoJRA. Conversely, IL-1 is likely more important in the inflammatory arthritis of JRA and in particular in the pathogenesis of RF+ polyarticular JRA. Our results suggest that cytokines have differing roles in JRA subtypes and likely reflect JRA subtype heterogeneity.     

Prevalence and concentration of IgM rheumatoid factor in polyarticular onset disease as compared to systemic or pauciarticular onset disease in active juvenile rheumatoid arthritis as measured by ELISA

The prevalence and concentration of IgM rheumatoid factor (RF) in children with juvenile rheumatoid arthritis (JRA) and its major disease onset groups remains uncertain. In our study enzyme linked immunoabsorbent assay (ELISA) of 68 children with active JRA showed IgM RF in the area of 67% (16/24) of those with polyarticular onset disease, 26% (7/27) of those with systemic onset disease, and 6% (1/17) of those with pauciarticular onset disease. The median IgM RF concentration was 50-fold higher in polyarticular disease compared to systemic disease. The prevalence of IgM RF in polyarticular disease was greater in those with severe disease (functional classes and 3 and 4), with 90% (9/10) seropositive. By agglutination assay, the prevalence of IgM RF in JRA was significantly less than by ELISA, with 33% of the polyarticular group positive for IgM RF, and none of the systemic group positive, Relatively low concentration IgM RF similar to that seen in systemic JRA was also found in high prevalence in the area of children with non-JRA, systemic rheumatic disease (n = 8). In summary, our study shows by ELISA that high concentrations of IgM RF are found essentially only in the sera of children with polyarticular onset JRA and especially in those with severe disease.     

Radiologic outcome and its relationship to functional disability in juvenile rheumatoid arthritis

OBJECTIVE: To determine the radiologic outcome in juvenile rheumatoid arthritis (JRA) and the relationship of radiologically detected joint damage to functional disability using multivariate analyses. METHODS: Selection criteria included a diagnosis of JRA made by 1977 American College of Rheumatology criteria, onset of arthritis > or = 5 years prior to study, current age > or = 8 years, a minimum grade 3 reading ability, and the availability of radiographs. Disability was measured by the Childhood Health Assessment Questionnaire (CHAQ) and Steinbrocker classifications. Radiographs taken within 2 years after onset (early) and the most recent radiographs (late) were examined by a single pediatric radiologist blinded to patients' identities, diagnoses, and outcomes. Multiple regression analyses were performed. RESULTS: On late radiographs the frequencies of joint space narrowing were 38, 14, 43, and 79%, respectively, among patients with systemic, pauciarticular, rheumatoid factor (RF) negative polyarticular, and RF positive polyarticular onset; erosions occurred in 63, 25, 39, and 75%, respectively. Early erosions were most frequent in patients with RF+ polyarticular onset, while both joint space narrowing and erosions occurred early in systemic onset. Radiologic signs of joint damage were most frequent at hips and wrists, while knees and ankles were relatively spared. Based on patients who had radiographs performed within one year of clinical study, 17.7% of the variation in CHAQ score was explained by joint space narrowing, 32.4% by pain, and 5% by a severe rating on physician's global estimate of disease activity. The odds of a Steinbrocker class > I were increased by joint space narrowing, pain, systemic onset, and active joint count. CONCLUSION: Differences in the frequencies and patterns of joint damage occur both among JRA onset subtypes and among individual joints. Radiographic damage, especially joint space narrowing, correlates with functional disability. However, pain is the major contributor to variation in CHAQ scores.     

Antibody to streptococcal cell wall peptidoglycan-polysaccharide polymers in sera of patients with juvenile rheumatoid arthritis but absent in isolated immune complexes

Sera of 88 children with juvenile rheumatoid arthritis (JRA) (10 seropositive, polyarticular onset, 29 seronegative, polyarticular onset, 32 pauciarticular onset, and 17 systemic onset) were evaluated for the presence of serum antibodies to streptococcal cell wall peptidoglycan-polysaccharide polymers (PG-PSP). Immune complexes (IC) isolated by the antihuman IgM (HIgM) affinity column method were also evaluated for the presence of antibodies to PG-PSP. Forty-one of 88 patients with JRA (7 of 10 seropositive, polyarticular onset, 11 of 29 seronegative, polyarticular onset, 16 of 32 pauciarticular onset, and 7 of 17 systemic onset) showed elevated levels of antibodies to PG-PSP in their sera. IgM rheumatoid factors (RF) were demonstrated in 70/88 isolated IC fractions of patients with JRA and IgG RF in 7; however, none of the patients demonstrated the presence of antibodies to PG-PSP in their isolated IC fractions from the anti-HIgM affinity column. These data indicate that antibodies are produced to PG-PSP in all JRA onset types, but they are not constituents of isolated IC by the anti-HIgM affinity column method.     

Analysis of the HLA-DR gene frequencies in Japanese cases of juveniles rheumatoid arthritis and rheumatoid arthritis by oligonucleotide DNA typing

Summary HLA-DR gene frequencies in 59 Japanese children with juvenile rheumatoid arthritis (JRA) and 62 Japanese adults with rheumatoid arthritis (RA) were analyzed by oligonucleotide DNA typing. As in other studies, the frequency of DRB1*0405 in RA patients was significantly higher than in the Japanese controls. In a comparison of non-calssified JRA patients with Japanese controls, no significant differences were observed in the frequency of DR types. However, when the JRA patients were classified into four clinical types, i.e., a rheumatoid factor-positive [RF(+)] polyarticular type, a rheumatoid factor-negative [RF(-)] polyarticular type, a pauciarticular type, and a systemic onset type, DRB1*0405 was found to be significantly higher in the RF(+) polyarticular JRA patients than in the controls (P>0.05). Thus, the RF(+) polyarticular type of JRA had the same HLA association as RA. This result is consistent with the fact that both RF(+) polyarticular JRA and RA cases have a similar clinical course.     

Clinical relevance of IgA rheumatoid factor (RF) in children with juvenile rheumatoid arthritis

This study proposed to investigate the prevalence and clinical relevance of serum immunoglobulin A (IgA) rheumatoid factor (RF) in juvenile rheumatoid arthritis (JRA) as published reports vary in their conclusion. Sera of 82 children with JRA and 25-age and sex-matched healthy children were measured for IgA RF by an enzyme linked immunoassay using human IgG as the antigen. Forty-three percent of the disease population were positive and the prevalence in pauciarticular, polyarticular and systemic onset was 9/18 (50%), 21/47 (44.7%) and 5/17 (27.7%) respectively when mean + 2SD of normal was taken as the cut-off value. By defining the upper limit of normal as mean + 6SD, 16/47 (34%) were positive in the polyarticular as compared to 2/18 (11.1%) in pauciarticular and 1/17 (5.8%) of systemic onset disease groups. The prevalence in the polyarticular subset with the upper cut-off limit was significantly higher than the pauciarticular and the systemic onset group (P < 0.05). Furthermore, the mean level of IgA RF was significantly higher in the polyarticular group compared to the mean level in the systemic onset group (P < 0.05). The mean level of IgA RF was also significantly higher (P < 0.05) in 61 children with active diseases. Received: 29 January 1999 / Accepted: 10 August 1999     

High prevalence of iga rheumatoid factor in severe polyarticular-onset juvenile rheumatoid arthritis,but not in systemic-onset or pauciarticular-onset disease

The presence of IgA rheumatoid factor (IgA-RF) has been correlated with severe joint disease in adult rheumatoid arthritis (RA), but IgA-RF has not been reported in juvenile rheumatoid arthritis (JRA). In the present study, IgA-RF was assayed by an enzyme-linked immunosorbent assay and was found in the sera of 14 of 24 children (58%) with active polyarticular JRA. The presence of IgA-RF correlated with the degree of functional disability. In contrast, IgA-RF was not found in the sera of systemic-onset disease patients, regardless of the degree of dysfunction. IgA-RF was detected in only 1 patient with pauciarticular disease, despite the fact that several patients in this group had severe disease. The presence of IgA-RF in polyarticular JRA did not correlate with serum IgA levels, but did correlate with the presence and the level of serum IgM-RF. Thus, the presence of IgA-RF appears to be specific for polyarticular JRA, and shows a correlation with severe disease in this group.     

DNA analysis of HLA-DR, DQ, and DP alleles in children with polyarticular juvenile rheumatoid arthritis.

HLA-DR, DQ and DP alleles were determined by restriction fragment length polymorphism analysis and oligonucleotide probe hybridization of polymerase chain reaction amplified genomic DNA in 94 Caucasian children with polyarticular juvenile rheumatoid arthritis (JRA) [13 rheumatoid factor (RF)+ and 81 RF-] and 100 healthy controls. HLA-DRw8, DQw4, DQA1*0401, DQB1*0402 were increased in frequency in those patients with RF seronegative disease, with highest frequencies seen in patients with young age at onset (< 5 years of age). These findings were similar to what we observed in children with pauciarticular JRA, especially those with young age at onset. DPB1*0301 was also found in increased frequency in the RF- group, and in particular those seronegative for antinuclear antibody. In contrast to what is observed in patients with pauciarticular JRA, the frequency of DPB1*0201 was not increased in any polyarticular JRA patient group. These data suggest that polyarticular JRA shares many genetic features with pauciarticular JRA.     

Growth patterns in juvenile rheumatoid arthritis

OBJECTIVE: To define patterns of growth in juvenile rheumatoid arthritis (JRA) and to evaluate possible associated clinical and laboratory correlates. METHODS: The study population comprised 67 children with JRA who had been followed for 5 years or longer and whose follow-up period did not extend beyond 18 years of age. Height and weight z scores were calculated with reference to age-related standards for each of the annual follow-up intervals and correlated with JRA subtype, the presence of rheumatoid factor (RF), the erythrocyte sedimentation rate (ESR), alkaline phosphatase level (ALP) and medication history. RESULTS: Initial height-for-age (HAZ) scores for pauciarticular, polyarticular and systemic JRA onset groups (PaJRA, PoJRA and SJRA respectively) were +0.27, -0.07 and +0.40 respectively. A significantly lower HAZ score in the SJRA population compared to the PaJIA population first became apparent at year 2 and the difference was maintained throughout the 9-year follow-up period. A significantly lower HAZ score in the SJRA population compared to the PoJRA population first became apparent at year 6 and the difference was maintained until the ninth year. During the 9-year follow-up period, RF-positive children tended to have negative HAZ scores whereas RF-negative children tended to have positive HAZ scores. The SJRA onset group displayed significantly lower HAZ scores, as compared to the HAZ score at onset, for 7 of the 9 subsequent follow-up intervals. Only 2 patients had heights < 2SD below the mean at final determination. Delay in generalized linear growth occurred predominantly in the SJRA population and to a lesser degree in those with PoJRA associated with RF positivity. CONCLUSIONS: Delay in linear growth occurs in some children with JRA. Patients with pauciarticular and RF-negative polyarticular disease can have growth patterns similar to normal children. Children with RF-positive polyarticular and systemic JRA have more significant growth retardation that occasionally can be sustained and extreme.     

Increased circulating vascular endothelial growth factor is correlated with disease activity in polyarticular juvenile rheumatoid arthritis.

OBJECTIVE: To investigate the relevance of vascular endothelial growth factor (VEGF) in the pathogenesis of juvenile rheumatoid arthritis (JRA). METHODS: Serum VEGF levels in 58 patients with JRA (systemic in 17, polyarticular in 29, pauciarticular in 12) were measured by ELISA and compared with those of 21 patients with infectious diseases and 50 healthy children. Correlations of VEGF levels with number of joints with active arthritis, erythrocyte sedimentation rate (ESR), and hyaluronic acid (HA) were examined. RESULTS: Serum levels of VEGF in patients with JRA were significantly higher than in healthy controls. Patients with systemic and polyarticular JRA showed statistically higher levels of VEGF than those with infectious diseases. VEGF levels correlated statistically with C-reactive protein (CRP) in patients with both infectious diseases and polyarticular JRA, but the regression slope (VEGF/CRP) was much steeper in polyarticular JRA than in infectious diseases. Serum VEGF levels correlated with disease activity variables such as the number of joints with active arthritis, ESR, and serum HA levels in polyarticular JRA. CONCLUSION: The correlation of serum VEGF levels and disease activity in polyarticular JRA suggests that VEGF may take an active part in joint inflammation.     

Expression of the rheumatoid factor cross-reactive idiotype in JRA: association with disease onset subtype, disease activity and disease severity.

We previously reported that approximately one-third of patients with juvenile rheumatoid arthritis (JRA) express high concentrations of antibodies marked by the rheumatoid factor cross reactive idiotype (RCRI) in their sera (6). In order to determine if an expression of RCRI is associated with certain clinical features of the disease, we prospectively studied 49 patients with JRA over a six month period, and determined serum RCRI concentrations by inhibition ELISA. RCRI concentrations correlated significantly with the duration of morning stiffness (r = .3866, p less than .01), and the functional class (p less than .001), but not with the number of active joints. Expression of RCRI was higher in patients with systemic onset disease (p less than .03), compared to patients with pauciarticular or polyarticular disease. In patients studied on more than one occasion, the RCRI expression was relatively constant despite changes in disease activity. A subset of JRA patients with systemic onset disease, higher serum concentrations of the RCRI.     

Circulating immune complexes and antinuclear antibodies in juvenile rheumatoid arthritis

Materials with the Clq binding properties of soluble immune complexes (IC) were found in sera from 11 of 51 consecutive (22%) children with juvenile rheumatoid arthritis (JRA) and in 17 of 20 adults with active sero-positive rheumatoid arthritis (RA). IC appeared more frequently in children with systemic onset disease whereas antinuclear antibody (ANA) was found more frequently in sera from those with pauciarticular disease. Only 3 JRA sera contained anti-immunoglobulin (rheumatoid factor); those 3 also had high Clq binding activities. Seven of 50 patients (14%) carried HLA-B27 but B27 was not associated with high Clq binding activity or presence of ANA. The presence of free ANA more frequently in children with mild disease and IC more frequently in children with relatively severe disease suggests that children with systemic JRA may have a relative defect in antibody-forming capacity or reticuloendothelial function which results in decreased clearance of circulating IC. Alternatively, systemic, polyarticular, and pauciarticular JRA may represent a spectrum of clinically similar diseases resulting from different etiologic agents.     

Serum IgM rheumatoid factor by enzyme-linked immunosorbent assay (ELISA) delineates a subset of patients with deforming joint disease in seronegative juvenile rheumatoid arthritis

Using human IgG as an antigen in an enzymelinked immunosorbent assay (ELISA), we looked for the presence of IgM rheumatoid factor (RF) in the sera of 74 children with juvenile rheumatoid arthritis (JRA). Nine children had RF detectable by both latex agglutination and ELISA. Forty-five percent (26 of 65) of the children who were seronegative by latex agglutination were found to be positive for IgM RF by ELISA. The prevalence of IgM RF was higher in patients with polyarticular onset disease (57.4%) than in those with pauciarticular onset (38.5%) or systemic onset (27.2%) disease. The prevalence of RF was higher in sera from patients with deforming joint disease than those without deformities (P<0.01).     

Disease course and outcome of juvenile rheumatoid arthritis in a multicenter cohort

OBJECTIVE: To determine the disease course and outcome in a multicenter cohort of patients with juvenile rheumatoid arthritis (JRA). METHODS: All patients with JRA seen at 3 pediatric rheumatology centers were identified from databases and/or clinic records. Inclusion criteria were a diagnosis of JRA (1977 American College of Rheumatology criteria), a followup period of at least 5 years since onset, and a minimum age of 8 years. Patients were examined and completed a Childhood Health Assessment Questionnaire (CHAQ). Kaplan-Meier curves were constructed to estimate rates of remission, relapse, and arthroplasty. Remission was defined as absence of active arthritis while off treatment for at least 2 years. Outcome measures were active disease duration, CHAQ scores, pain determined by visual analog scales, physician's global assessments, and Steinbrocker functional classifications. Years of education and employment status were ascertained. RESULTS: We studied 392 patients of 652 (60%) who met the selection criteria. The probabilities of remission at 10 years after onset were 37, 47, 23, and 6% for patients with systemic, pauciarticular, RF- polyarticular, and RF+ polyarticular JRA, respectively. The probability of relapse varied from 30 to 100% at 15 years. The probability of arthroplasty varied from 13 to 57% after 15 years of active disease. We found 2.5% of patients assessed were in Steinbrocker Classes III or IV and 6% were in the highest CHAQ score (> 1.5) group. Compared with national statistics, fewer female patients received post-secondary education and unemployment rates for patients 20 to 24 years of age were higher. CONCLUSION: Our results indicate that JRA is a disease that often extends into adulthood. Compared to previous decades, functional outcome has improved; however, the estimated rate of arthroplasty remains very high. Patients with JRA may have difficulty entering the workforce.     

The immunogenetics of juvenile rheumatoid arthritis.

Recent major advances in understanding the genetic structure of the human leukocyte antigen (HLA) region and how HLA molecules contribute to immune responses have been paralleled by more precise identification of specific HLA genes conferring susceptibility to the various forms of juvenile rheumatoid arthritis (JRA). This article presents current models for HLA-associated autoimmune disease susceptibility and summarizes the HLA Class II alleles currently known to be associated with JRA: primarily DR8, DR5, DR6, and DPw2.1 in pauciarticular onset JRA; and DR4 in rheumatoid factor-positive polyarticular onset JRA. Rheumatoid factor-negative polyarticular onset JRA and systemic onset JRA are variously associated with several of these same genes. Gene interactions and the clinical utility of HLA typing in this disease are also discussed.     

T/non-T and CD4/non-T cell autologous mixed lymphocyte reactions in juvenile rheumatoid arthritis

Proliferation of T and CD4 cells in the autologous mixed lymphocyte reaction (AMLR) was determined for children with juvenile rheumatoid arthritis (JRA) and children with other rheumatic and connective tissue diseases. Children with musculoskeletal symptoms but no rheumatic disease and healthy adults served as controls. Patients with polyarticular rheumatoid factor (RF) positive JRA had a diminished CD4/non-T cell AMLR, whereas those with RF negative polyarticular and pauciarticular onsets had normal results.     

Antibodies against cyclic citrullinated peptide are associated with HLA–DR4 in simplex and multiplex polyarticular‐onset juvenile rheumatoid arthritis

Objective

Anti–cyclic citrullinated peptide (anti‐CCP) antibodies have been detected in patients with juvenile rheumatoid arthritis (JRA), particularly in those with polyarticular, rheumatoid factor (RF)‐positive JRA. Our objectives were to determine whether anti‐CCP antibodies are associated with HLA–DR4 in children with polyarticular JRA, whether anti‐CCP antibodies are associated with clinical features of disease, and whether affected sibling pairs (ASPs) with JRA are concordant for this antibody.

Methods

Stored serum samples obtained from 230 HLA‐typed patients with JRA (77 with polyarticular‐onset disease and 153 with pauciarticular‐ or systemic‐onset disease), 100 JRA ASPs, and 688 healthy children were tested for anti‐CCP antibodies and RF.

Results

Thirteen percent of the patients with polyarticular‐onset JRA and 2% of the other JRA patients exhibited anti‐CCP antibodies, compared with only 0.6% of the controls. Fifty‐seven percent of RF‐positive patients with polyarticular‐onset JRA had anti‐CCP antibodies. HLA–DR4–positive patients with polyarticular‐onset JRA were more likely to have anti‐CCP antibodies than were those without HLA–DR4 alleles (odds ratio [OR] 5.20, 95% confidence interval [95% CI] 1.30–20.9). Anti‐CCP antibodies were associated with polyarticular onset (OR 7.46, 95% CI 1.99–28.0), a polyarticular disease course (OR 9.78, 95% CI 1.25–76.7), and erosive disease (OR 14.3, 95% CI 3.01–67.9). Concordance rates for anti‐CCP antibodies among ASPs were statistically significant.

Conclusion

These data demonstrate increased anti‐CCP antibody formation in HLA–DR4–positive patients with polyarticular‐onset JRA. The overall prevalence of anti‐CCP antibodies in JRA is low, but a substantial proportion of RF‐positive patients with polyarticular‐onset JRA have these antibodies. Anti‐CCP antibodies in JRA are associated with polyarticular onset, a polyarticular course, and erosive disease.

     

Complement-fixing hidden rheumatoid factor in juvenile rheumatoid arthritis

Fifteen to twenty percent of patients with juvenile rheumatoid arthritis (JRA) have positive latex fixation tests (LFT), whereas approximately 46% have previously been demonstrated to have hidden rheumatoid factors (RF), i.e., 19S IgM RF which can be detected by the LFT after acid separation of the IgM-containing fraction from serum. In this study, hidden RF were found in 59% of patients with seronegative JRA by use of a complement-dependent hemolytic assay. The median titer of JRA patients was 1:42, and in healthy and disease controls it was 1:7. The difference was significant at P < 0.001. When data from patients with active disease were analyzed separately, the median titer for polyarticular JRA was 1:97 and for pauciarticular JRA, 1:91. The differences due to active disease were significant at P < 0.001 and P < 0.005, respectively. The results demonstrate that the hemolytic assay is more sensitive than the LFT in determining the presence of hidden RF, and activity of disease correlates well with high hemolytic RF titers.     

JUVENILE RHEUMATOID ARTHRITIS IN AUCKLAND: A LONG TERM FOLLOW-UP STUDY WITH PARTICULAR REFERENCE TO UVEITIS

Abstract Although features of juvenile rheumatoid arthritis (JRA) have been well described in British, American, and to a lesser extent Australian communities we can find no previous study of the clinical characteristics of this disease in a New Zealand population or indeed in any population containing Polynesians. In a follow-up study of 55 Auckland residents with juvenile rheumatoid arthritis, current information was obtained for 78% of the study group with a mean interval from disease onset to follow up of 9.3 years. The outcome for the group as a whole was excellent although patients with a polyarticular course, regardless of onset subtype, had a poorer outcome with respect to both ongoing disease activity and functional disability. Polynesian patients were represented in all onset subtypes in proportion to their frequency in the general community and there was no recognisable influence of race on the course of the disease. Despite careful ophthalmological examination only one case of mild uveitis was detected, a much lower incidence than in British and American reports.     

Differences in disease outcomes between medicaid and privately insured children: possible health disparities in juvenile rheumatoid arthritis

OBJECTIVE: To determine the relationship between health insurance status and disease outcome in children with juvenile rheumatoid arthritis (JRA). METHODS: JRA patients followed at a tertiary pediatric rheumatology center were assessed for the number of active joints and number of joints with limited range of motion. Disease activity, patient well-being, and pain were measured. Disability was assessed by the Childhood Health Assessment Questionnaire, health-related quality of life by the Pediatric Quality of Life Inventory (PedsQL) Generic Core Scale, and the PedsQL Rheumatology Module. Health care resource utilization was estimated based on the number of billing events for health services coded in administrative databases; these databases also provided information on patient health insurance status. Children insured by Medicaid or similar state programs for low-income families were considered to have Medicaid status. Disease outcomes of children with Medicaid status was compared with that of children with private health insurance. RESULTS: Forty (14%) of the 295 children with JRA had Medicaid status. Patients with Medicaid status were more often of nonwhite race (P < or = 0.04) and more frequently had a polyarticular or systemic disease course (P = 0.04) compared with other patients (n = 255). After correction for differences in disease duration, race, JRA onset, and JRA course between groups, children with Medicaid status continued to have significantly higher disability (P < 0.0003), and lower mean PedsQL Generic Core Scale scores (P < 0.05), while health resource utilization appeared similar between groups. CONCLUSION: Despite apparently similar health resource utilization and joint involvement, Medicaid status is associated with significantly lower health-related quality of life and higher disability in JRA.