Association between duration of symptoms and severity of disease at first presentation to paediatric rheumatology: results from the Childhood Arthritis Prospective Study

Objectives. To study the association between disease severity at first presentation to paediatric rheumatology (PRh) and length of time since symptom onset in children recruited to the Childhood Arthritis Prospective Study. Methods. Children ≤16 yrs with inflammatory arthritis persisting ≥2 weeks were recruited from five UK hospitals. Data including demographics, disease features, Childhood Health Assessment Questionnaire (CHAQ), physician and parent global assessment and blood tests were collected at the first appointment with PRh (baseline). The association between symptom duration (defined as time from first reported symptom onset to presentation at PRh) and baseline disease characteristics was evaluated using non-parametric descriptive statistics and multivariable logistic regression analyses. Results. Five hundred and seven children (65% female) were included: median age at onset was 6.8 yrs. Two hundred and thirty-three had oligoarthritis, 68 had RF-negative polyarthritis, 27 had systemic onset arthritis and 29 had arthritis that was not JIA. The median symptom duration was 4.6 months. Median symptom duration was shortest for children presenting with systemic arthritis (1.6 months) and longest for those with PsA (8.6 months). Children with a longer duration of symptoms were older and had higher median active joint counts but lower median ESR. Symptom duration did not correlate with CHAQ score at presentation. Conclusions. Children who have systemic arthritis had the shortest delay to PRh presumably because they are profoundly unwell. Children with joint pain/stiffness but normal ESR had longer delays suggesting that if blood tests do not indicate inflammation, the diagnosis of JIA may be overlooked.