Predictors of 2 year outcomes of juvenile idiopathic arthritis in a multicenter Canadian cohort: the ReACCh out experience

1546-0096-10-S1-A40 1546-0096 Poster presentation Predictors of 2 year outcomes of juvenile idiopathic arthritis in a multicenter Canadian cohort: the ReACCh out experience ShiffJNatalie OenGKiem GuzmanJaime JohnsonANicole HuberAdam TseShirley TuckerBLori YeungSMRae DuffyMCiaran ReACCh Out Investigators

Alberta Children's Hospital, Calgary, AB, Canada

BC Childrens Hospital, Vancouver, BC, Canada

Hospital for Sick Children, Toronto, ON, Canada

IWK Health Centre, Halifax, NS, Canada

Montreal Children's Hospital, Montreal, QC, Canada

University of British Columbia, Vancouver, BC, Canada

University of Manitoba, Winnipeg, MB, Canada

University of Saskatchewan, Saskatoon, SK, Canada

Pediatric Rheumatology 2011 Pediatric Rheumatology Symposium: AbstractsBrian M Feldman and Laura E SchanbergMeeting abstracts2011 Pediatric Rheumatology Symposium sponsored by the American College of RheumatologyMiami, FL, USA

2-5 June 2011

1546-0096 2012 10 Suppl 1 A40 http://www.ped-rheum.com/content/10/S1/A40 10.1186/1546-0096-10-S1-A40 1372012 2012Shiff et al; licensee BioMed Central Ltd.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Purpose

The ability to predict which children with Juvenile idiopathic Arthritis (JIA) are likely to have worse outcomes would allow a more targeted aggressive approach to initial therapy. We used data from the Research on Arthritis in Canadian Children Emphasizing Outcomes (ReACCh Out), a 16-centre prospective inception cohort of children with newly diagnosed JIA, to identify predictors of 2-year outcomes present during the first 6 months after enrollment.

Methods

Data was available on 223 to 291 children depending on the analysis. The 2-year clinical outcomes were remission, a Childhood Health Assessment questionnaire (CHAQ) score of ≥0.75, and the Juvenile Arthritis Quality of Life Questionnaire (JAQQ) score. Remission was defined according to Wallace criteria (without ESR or CRP), and combined patients on and off medication. The candidate predictors listed in Table 1 were selected for their clinical relevance and forced in a stepwise manner into regression models. They underwent natural logarithmic transformation (Ln) if not normally distributed. Logistic regression was used for prediction of remission and CHAQ outcomes, and linear regression for the JAQQ score.

Table 1

Resuts of regression models using basline and 6 month variables to predict 24 month remision, CHAQ ≥ 0.75, and JAQQ score.

Outcome at month 24

Regression

Candidate predictor

OR or β at month 0 (95% CI)

OR or β at month 6 (95% CI)

Remission

223

Logistic

Ln (number of active joints)*

0.72 (0.55, 0.95)

0.63 (0.47, 0.85)

0.52 (0.14, 2.00)

0.51 (0.13, 1.99)

Ln (CHAQ at month 0)*

0.61 (0.33, 1.12)

0.49 (0.25, 0.98)

Ln (onset to first visit)^§

0.92 (0.68, 1.25)

0.92 (0.67, 1.26)

Ln (age of onset)^#

1.07 (0.76, 1.51)

1.16 (0.82, 1.64)

CMAQ ≥ 0.75

291

Logistic

CHAQ ≥ 0.75 at momth 0

7.47 (2.48, 22.46)

2.17 (0.68, 6.89)

Ln (number of active joints )*

1.02 (0.72, 7.43)

1.25 (0.87, 1.78)

2.14 (0.67, 6.66)

2.38 (0.72, 7.92)

Ln (JAQQ at month 0)

1.56 (0.34, 7.10)

2.38 (0.73, 7.75)

Interaction JAQQ x CHAQQ

1.04 (0.90, 1.21)

1.22 (0.94, 1.59)

JAQQ

270

Linear

Ln (JAWW at month 0)

0.34 (0.02, 0.78)

0.75 (0.42, 1.07)

Ln (CHAQ at month 0)*

0.43 (-0.06, 0.92)

-0.12 (-0.64, 0.26)

-0.05 (-0.60, 0.50)

-0.10 (-0.58, 0.38)

Ln (age of onset)^#

0.12 (-0.05, 0.28)

0.00 (-0.15, 0.15)

Enthesitis^¶

0.01 (-0.35, 0.38)

-0.04 (-0.41, 0.33)

Interaction JAQQ x CHAQQ

-0.01 (-0.09, 0.07)

0.15 (0.05, 0.26)

*0.5 was added to variable prior to Ln transformation

^§ time in months

^# age in years

^¶ by history or physical exam

Results

Table 1 shows results of the regression models. The only significant independent predictor of remission at both month 0 and 6 was the number of active joints, but R² was low (0.06 and 0.09 at month 0 and month 6 respectively). A CHAQ score ≥0.75 was a strong independent predictor of a high 24-month CHAQ at month 0 but not at month 6 (R² of 0.22 and 0.24 respectively). The JAQQ score at both month 0 and month 6 was the only significant independent predictor of the 24 month JAQQ score (R² of 0.09 and 0.23 respectively). There was a non-statistically significant trend for rheumatoid factor positivity to be associated with lesser chance of remission and CHAQ score ≥0.75 at 24 months.

Conclusion

As hypothesized, most measures at 6 months were better than the baseline measures at predicting 2 year outcomes. Interestingly, CHAQ score at baseline seemed a better predictor of 2 year outcome than CHAQ score at 6 months. Although only a single variable was a significant independent predictor of the outcomes in each model, all 3 models explained a larger proportion of variation in the outcome when the additional variables were included. These results highlight the relatively limited ability to predict disease course at early stage of disease, and should act as an impetus for further research into relevant clinical and biochemical markers of outcome.

Disclosure

Natalie J. Shiff: None; Kiem G. Oen: None; Jaime Guzman: None; Nicole A. Johnson: None; Adam Huber: None; Shirley Tse: None; Lori B. Tucker: None; Rae S.M. Yeung: None; Ciaran M. Duffy for the ReACCh Out Investigators: None.