Outcome in patients with enthesitis related arthritis (ERA): juvenile arthritis damage index (JADI) and functional status.

Background: Data on outcome of ERA is scarce and there is lack of well-accepted tools. JADI is a newly described outcome measure in JIA that has not been evaluated in ERA. We studied outcome in ERA using JADI and correlated it with traditional outcome measures.

Methods: We studied 49 consecutive patients of ERA with age >/= 5 years and duration >/= 1 year. Along with JADI, we recorded enthesitis, lumbar spinal anterior flexion by modified Schober's method, presence of inflammatory backache, loss of school years, HAQ-S, growth and pubertal delay. Parent's/patient's and physician's global assessments on 100 mm visual analogue scale.

Results: The median age was 18.0 (10-27) years and the median duration of disease was 6.0 (1-17) years. All the patients were male and half (53.1%) were HLA B 27 positive. Fourteen had decreased anterior lumbar flexion movement and 32 had inflammatory backache. Active enthesitis was present in 63.3%. Functionally, mild, moderate and severe disability was seen in 18.4%, 34.7% & 14.3% respectively. Sixty five percent of patients lost education years. Twenty-eight patients had damaged joints with median of 2.0 joints (0-9). Seventeen patients (34.7%) had damaged joints in JADI-A score with a median of 1.0 (0-12). Growth failure was the commonest extra articular damage (8.2%) in JADI-E. JADI correlated with HAQ-S, parent's or patient's & physician's global assessment (p < 0.01). Limitation of spinal mobility had high correlation with HAQ-S; correlation with JADI-A was low.

Conclusion: Three fourth of the ERA patients had functional limitations. Half of the patients had damaged joints. Even though JADI correlated well with traditional outcome measures, it underestimates joint damage, and does not assess enthesitis and spinal limitation which affect functional status in ERA. Inclusion of these may make it more useful for ERA.