A modified juvenile arthritis damage index to improve articular damage assessment in juvenile idiopathic arthritis--enthesitis-related arthritis (JIA-ERA).

Juvenile arthritis damage index (JADI) consists of two parts which measure articular (JADI-A) and extra-articular (JADI-E) damage in patients with juvenile idiopathic arthritis (JIA). It does not include assessment of cardiac dysfunction and joint areas commonly affected in enthesitis-related arthritis (ERA) category of JIA. We have tried to study if modification of JADI will improve its performance in JIA-ERA. We studied 101 consecutive patients of JIA-ERA. JADI-A was modified (JADI-AM) to include damage assessment of tarsal joints and lumbar spine. JADI-E was modified (JADI-EM) to include assessment of symptomatic cardiac dysfunction. The performances of the modified and standard JADI were compared. Ninety-seven patients were male. The median age was 18 years (9-36). At a median disease duration of 6 years (1-24), joint damage was observed in 47 as assessed by JADI-A. JADI-AM could identify 11 more patients (N = 58) with articular damage. JADI-AM had good correlation with number of joints with limitation of movement (Spearman's [rS] = 0.9) and low to moderate correlation (rS < 0.7) with measures of disease activity and functional status. JADI-AM discriminated well among patients with different disability levels. Extra-articular damage was observed in 35, and modification of JADI-E with inclusion of cardiac dysfunction did not identify any additional patient. Thus, we propose a modification of the JADI-A (JADI-AM). In JIA-ERA, modification of JADI-A improves its ability to identify articular damage. Modification of the JADI-E may not be needed as symptomatic cardiac involvement is rare.