BIRMINGHAM, ENGLAND — Referral of a child with inflammatory arthritis is likely to be delayed if diagnosis is based solely on blood tests and not on physical findings, according to initial study results presented at the annual meeting of the British Society for Rheumatology.
Faced with a paucity of data, researchers launched the first large-scale prospective study to assess a relationship between presenting symptoms and time to juvenile arthritis diagnosis. “Studies have not included all children with juvenile arthritis. They have been retrospective case reviews or cross-sectional studies. We decided to include all comers and look at them over 5 years,” Dr. Kimme Hyrich commented in an interview during a poster session at the meeting.
The Childhood Arthritis Prospective Study (CAPS) includes children aged 16 years or younger with new inflammatory arthritis in at least one joint that persists for 2 weeks or more. Not surprisingly, results among the first 494 participants indicate that children who present with clear diagnostic signs wait the shortest time before seeing a pediatric rheumatologist. However, children who present with joint pain or stiffness but normal erythrocyte sedimentation rate (ESR) tend to experience a long delay before reaching specialty care, even if they have a high joint count.
An unexpected finding was how long a significant minority of patients waited, Dr. Hyrich said. “It is concerning that one-fifth of children had to wait more than 1 year.” Dr. Hyrich is a clinical lecturer and consultant rheumatologist, Arthritis Research Campaign Epidemiology Unit, the University of Manchester, England.
The median age of participants is 7 years. A total of 64% are girls, 49% have oligoarthritis, and 14% have rheumatoid factor-negative polyarthritis. The remainder was equally divided among other subtypes of inflammatory arthritis.
About 30% of referrals to the CAPS study come from general practitioners, 30% from general pediatricians, and 20%–30% from orthopedists. The remainder comes from various other sources, Dr. Hyrich said.
The median overall time from symptom onset to pediatric rheumatology consult was 3.9 months. Referrals were quickest when the child experienced a related casualty (1.2 months). General practitioner referrals were a median 4.8 months after symptom onset, and referrals from other medical specialists took a median 6.5 months.
If a child presents with foot pain and no laboratory evidence of arthritis, for example, the diagnosis might not be complete, Dr. Hyrich said. “The doctor might think it is a mechanical issue.”
The median total delay was longest for rheumatoid factor-positive children with polyarthritis (7.2 months) and shortest for children with systemic arthritis (1 month).
Participants who waited 4 months or more before seeing a pediatric rheumatologist were more likely to be older (median 8 years vs. 6 years), to have a higher joint count (median 2 vs. 1), and to have a lower ESR (14 mm/hour vs. 32 mm/hour), compared with children who were seen sooner. There were no significant differences between the shorter and longer delay groups on the Childhood Health Assessment Questionnaire, Physician's Global Assessment, Parent's General Evaluation of Well-Being, or pain scores.
The findings indicate that if blood tests do not indicate inflammation, the diagnosis of juvenile inflammatory arthritis might be overlooked and the initiation of appropriate therapies delayed, Dr. Hyrich said.
“The study is ongoing. Our ultimate aim is to recruit about 1,100 children, and now we have about 600.”