Agreement between physicians and parents in rating functional ability of children with juvenile idiopathic arthritis

OBJECTIVE To investigate concordance between physicians and parents in rating the degree of functional ability of children with juvenile idiopathic arthritis (JIA). METHODS The attending physician and a parent were asked to rate independently the level of physical functioning of 155 patients with disease duration >/= 5 years on a 6-point scale ranging from 1 = no disability (i.e. the child can do without difficulty all activities that children of his/her age can do) to 6 = severe disability (i.e. all activities are difficult for the child). At study visit, measures of JIA activity and damage were assessed. Agreement was evaluated with weighted kappa (<0.40 = poor agreement; 0.41-0.60 = moderate agreement; 0.61-0.80 = substantial agreement; >0.80 excellent agreement). Physician/parent evaluations were divided in 3 groups: 1) concordance; 2) parent over-rating = parent assessment over-rated relative to physician assessment; 3) physician over-rating = physician assessment over-rated relative to parent assessment. Factors affecting concordance/discordance were evaluated by means of Kruskal-Wallis or Chi-square/Fisher exact test. RESULTS Concordance, parent over-rating and physician over-rating were observed in 107 (69%), 29 (18.7%) and 19 (12.3%) evaluations, respectively. Kappa value was 0.69. Parent over-rating was associated with greater intensity of pain (p = 0.01) and higher Childhood Health Assessment Questionnaire (C-HAQ) score (p = 0.004), whereas physician over-rating was associated with more severe joint disease (p = 0.04 to <0.001), higher C-reactive protein (p = 0.03) higher frequency of Steinbrocker functional class = II (p < 0.001), and greater articular damage, as measured with the Juvenile Arthritis Damage Index (p < 0.001). CONCLUSION Physicians and parents revealed fair concordance in rating functional ability of children with JIA. Parent over-rating was associated with greater child's pain and worse C-HAQ score, whereas physician over-rating was associated with greater severity of joint inflammation and damage.