Correlates of disablement in polyarticular juvenile chronic arthritis--a cross-sectional study

To assess the impact of disease on the functional outcome of patients with polyarticular juvenile chronic arthritis (JCA), the relationship between impairments and functional limitations was studied. Therefore, variables from the impairment domain were correlated with variables of the functional limitation domain and outcome variables were analysed for differences as a result of inflammatory disease, rheumatoid factor (RF), disease duration and age at onset. Twenty-three patients with polyarticular JCA were subjected to auxologic evaluation, a laboratory check, radiographic evaluation, joint count on tenderness and swelling, joint mobility/deformity examination, functional assessment of skills, health assessment and psychosocial evaluation. Inflammatory disease parameters, like CRP, ESR, thrombocytosis and leucocytosis, were increased in 6/23 patients. The parameters of the impairment domain, like joint tenderness and swelling, showed mild outcome, while parameters of the functional limitation domain showed more severe outcome. Generally, perceived competence was found to be normal. A clinically relevant number of patients (10/13) showed low scores on the activity factor of the Child Behaviour Check List (CBCL). A significant relationship was found between inflammatory disease variables and functional limitation outcome. RF seropositivity was not a good outcome predictor. Disease duration and age of onset showed no significant difference in the outcome of the domains. Significant correlation was found between the parental report of the Childhood Health Assessment Questionnaire (CHAQ) and all impairment parameters. Joint swelling showed a significant relationship with CHAQ and Juvenile Arthritis Functional Assessment Report (JAFAR). Disability outcome did not correlate with functional limitation. In general, children with polyarticular JCA function rather well when using a multidomain evaluation approach. Compensatory and adaptational mechanisms might contribute to the poor correlation between impairment and functional limitation parameters. Laboratory evaluation of inflammatory disease, a joint count of swollen joints and parent's report of the child's health status related best in our study.