Table 3

Association of clinical features with the risk of any flare after attaining inactive disease

CharacteristicPatients with feature (%)Crude HR*95% CIp ValueAdjusted HR*95% CIp Value
Systemic arthritis5.90.670.46 to 0.970.0330.600.40 to 0.910.015
RF-positive polyarthritis3.01.921.29 to 2.870.0011.530.99 to 2.390.057
DMARD before inactive disease42.11.281.09 to 1.500.0020.960.77 to 1.210.762
Biological agents before inactive disease6.71.651.22 to 2.230.0011.310.94 to 1.840.115
Greater than 52 weeks to attain inactive disease33.11.281.09 to 1.500.0021.150.95 to 1.390.146
Maximum joint count before inactive disease >435.31.461.23 to 1.74<0.0011.150.90 to 1.460.270
Maximum PGA before inactive disease >30 mm50.61.501.27 to 1.78<0.0011.321.08 to 1.620.007
Involvement of a high-risk joint† to 1.470.0041.010.82 to 1.250.913
ANA positive‡ to 1.430.0171.150.96 to 1.370.122
  • *Crude HRs were calculated in Cox regression models that included only one independent variable at a time. Adjusted HRs were calculated in a multivariable Cox regression model that included all statistically significant variables (p<0.05) at once. All variables were dichotomised so that HRs may be interpreted as relative risks. For JIA categories, the HR compares children in that JIA category with children in all other JIA categories. A round number close to the median was chosen to dichotomise continuous variables. The HRs of continuous variables without dichotomisation were examined in separate models and did not change the statistical significance of the association (data not shown).

  • †High-risk joints included any of neck, wrist, sacroiliac, hip or ankle.16

  • ‡An ANA titre above the cut-off for the local laboratory (usually 1:80).

  • ANA, antinuclear antibodies; DMARD, disease-modifying antirheumatic drug; JIA, juvenile idiopathic arthritis; PGA, physician global assessment; RF, rheumatoid factor.