Background/Purpose: Enthesitis related arthritis (ERA) is the commonest category of JIA seen in India and constitutes 30-40% of all JIA patients. There are many studies on long term outcomes in adult Spondyloarthritis but the data in children with ERA is scant. The available data is also mostly from developed countries. Thus, we studied outcome of ERA in adulthood in resource constrained setting where there is limited availability of anti-TNF agents.

Methods: Patients with ERA (ILAR classification) having >5 years of disease and above the age of 18 years were included in the study. Data on clinical features, Bath indices (BASMI, BASDAI, BASFI), health assessment questionnaire disability index (HAQ DI) was collected. CRP was measured by Nephelometry. X-ray pelvis including hips was obtained and compared with baseline X-ray available at first visit to our hospital for progression of radiological sacroiliitis and hip arthritis. The X-rays were assessed by two radiologists. In addition, fulfilment of adult criteria of Spondyloarthropathy (SpA), assessment of Spondylarthritis International Society (ASAS) and modified New York (NY)] were assessed.

Results: 73 patients (72 male) of median age 20 (18-23) years and median disease duration of 8 (5.5-11) years were recruited. There was delay in diagnosis of 4 (1.75-6) years. Nearly all (96%) had active disease (BASDAI >0) and median CRP was 2.1 (0.6-4.8) mg/dl. Three-fourth (75.3%) had functional disability (HAQ DI >0) and median BASFI was 1.95 (0.6-3.5).  67 patients fulfilled axial ASAS criteria, while 71 fulfilled peripheral SpA criteria.

Overall, 81% had radiological sacroiliitis and 37% had hip involvement. Nearly half (46.6%) of the patients had radiological progression in sacroiliitis and one-fourth (25%) had progression of hip arthritis over 3.5 (2.5-5.5) years. Patients with radiological sacroiliitis had higher CRP (2.5 vs 1 mg/dl) and more hip arthritis (37 vs 7%) than those without it.

Those with radiological hip arthritis had longer delay in diagnosis (6 vs 3 years) than those without it. They also had higher BASDAI, BASMI, BASFI and HAQ DI. Hip arthritis correlated with radiological sacroiliitis (r= 0.301). Fulfillment of modified NY criteria was seen more often in patients with hip arthritis (95% vs 63%; p< 0.002) (Table 1).

Conclusion: Most adults with ERA have active disease even after 8 years of disease Hip involvement is associated with poorer outcome.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/hip-involvement-leads-to-poor-outcome-in-adulthood-in-children-with-enthesitis-related-arthritis-era-category-of-juvenile-idiopathic-arthritis-jia/