To define patterns of growth in juvenile rheumatoid arthritis (JRA) and to evaluate possible associated clinical and laboratory correlates.
The study population comprised 67 children with JRA who had been followed for 5 years or longer and whose follow-up period did not extend beyond 18 years of age. Height and weight z scores were calculated with reference to age-related standards for each of the annual follow-up intervals and correlated with JRA subtype, the presence of rheumatoid factor (RF), the erythrocyte sedimentation rate (ESR), alkaline phosphatase level (ALP) and medication history.
Initial height-for-age (HAZ) scores for pauciarticular, polyarticular and systemic JRA onset groups (PaJRA, PoJRA and SJRA respectively) were +0.27, -0.07 and +0.40 respectively. A significantly lower HAZ score in the SJRA population compared to the PaJIA population first became apparent at year 2 and the difference was maintained throughout the 9-year follow-up period. A significantly lower HAZ score in the SJRA population compared to the PoJRA population first became apparent at year 6 and the difference was maintained until the ninth year. During the 9-year follow-up period, RF-positive children tended to have negative HAZ scores whereas RF-negative children tended to have positive HAZ scores. The SJRA onset group displayed significantly lower HAZ scores, as compared to the HAZ score at onset, for 7 of the 9 subsequent follow-up intervals. Only 2 patients had heights < 2SD below the mean at final determination. Delay in generalized linear growth occurred predominantly in the SJRA population and to a lesser degree in those with PoJRA associated with RF positivity.
Delay in linear growth occurs in some children with JRA. Patients with pauciarticular and RF-negative polyarticular disease can have growth patterns similar to normal children. Children with RF-positive polyarticular and systemic JRA have more significant growth retardation that occasionally can be sustained and extreme.