Table 4.

Standardized incidence ratios compared to ADHD cohort for all malignancy for the JIA medication exposure groups by certainty of malignancy outcome based on comprehensive review of entire claims histories.

Cohort	Standardized Incidence Ratios for All Malignancy (95% CI)
	All Identified Incident Malignancies	Probable and Highly Probable Incident Malignancies	Highly Probable Cases Incident Malignancies
All children with JIA	3.3 (1.6–6.1)	4.4 (1.8–9.0)	3.3 (0.9–8.5)
JIA unexposed	4.6 (1.7–10)	6.9 (2.3–16)	6.2 (1.4–17)
JIA MTX without TNF inhibitor	3.3 (0.7–9.5)	3.9 (0.4–14)	2.3 (0.01–14)
JIA any TNF inhibitor	1.6 (0.03–8.3)	0 (0–9.7)	0 (0–13)

Highly probable was defined as >2 ICD-9 codes for the same form of malignancy and evidence of cancer treatment. Probable was defined as >2 ICD-9 codes for the same malignancy over a period of more than 1 month OR ≤ 2 ICD-9 codes for the same malignancy and evidence of cancer treatment.

JIA = juvenile idiopathic arthritis; ADHD = attention-deficit hyperactivity disorder; MTX = methotrexate or leflunomide; TNF inhibitor = etanercept, infliximab, or adalimumab; ICD-9 = International Classification of Disease, Ninth Revision