Rates of malignancy associated with juvenile idiopathic arthritis and its treatment
A partir de la base de données américaine Medicaid portant sur la période 2000 à 2005, cette étude analyse l'incidence de tumeurs malignes chez des enfants atteints d'arthrite chronique juvénile
Objective: To determine relative rates of incident malignancy among children with juvenile idiopathic arthritis (JIA) with respect to treatment compared to children without JIA Methods: Using national U.S. Medicaid data from 2000 through 2005, we identified cohorts of children with JIA and without JIA using physician diagnosis codes and dispensed medication prescriptions. Study follow-up began after a 6 month lag period to exclude prevalent and misdiagnosed malignancies. Treatment with methotrexate and TNF inhibitors was categorized as ever or never exposed. Malignancy outcomes were identified using an adapted version of a previously validated algorithm. Incident malignancies were categorized as possible, probable, or highly probable based on a comprehensive review of all claims. Malignancy rates were standardized to the age, sex, and race distribution of the overall JIA cohort. Standardized incidence ratios (SIR) were calculated using children without JIA (N=321,821) as the referent group. Results: The JIA cohort included 7,812 children with a total follow-up time of 12,614 person-years, of whom 1,484 children contributed 2,922 person-years of TNF inhibitor exposure. For all children with JIA versus children without JIA, the SIR was 4.4 (1.8-9.0) for probable and highly probable malignancies. For methotrexate users without TNF inhibitor use, the SIR was 3.9 (0.4-14). Following any use of TNF inhibitors, no probable or highly probable malignancies were identified (SIR 0 (0-9.7)). Conclusions: Children with JIA appeared to have an increased rate of incident malignancy compared to children without JIA. JIA treatment, including TNF inhibitors, did not appear significantly associated with the development of malignancy.