Background/Purpose:  Recent data suggests that achievement of inactive disease and early disease remission may result in improved outcomes for patients with juvenile idiopathic arthritis (JIA).  Objectives of our study were to examine the probabilities of achieving i) active joint count (AJC)= 0; ii) inactive disease; and iii) disease remission for patients treated with contemporary treatments in a large prospective longitudinal inception cohort of patients with JIA.

Methods: ReACCh Out recruited consecutive patients diagnosed with JIA at 16 sites across Canada (Jan 2005 – Dec 2010), with prospective data collection every 6 months for the first 2 years, then yearly.  Clinical information included the six ACR core outcome measures and medications.  Inactive disease was defined as active joint count (AJC) =0, absence of systemic symptoms, enthesitis or uveitis and a physician global activity (PGA) of < 1 cm on a 10 cm VAS.  Remission was defined as ≥ 12 months with inactive disease with no anti-rheumatic or anti-uveitis medications.   Descriptive statistics (median and interquartile range (IQR)) and Kaplan-Meier Survival analyses were examined; patients were censored at their last study visit or study end date.

Results: 1104 patients with newly diagnosed (≤ 6 months) active JIA with ≥1 follow-up visit were analyzed.  Patients were predominantly female (63%), age at diagnosis was 9.3 (3. 9, 13.0) years. Time from diagnosis to enrollment was 0.3 (0, 1.6) months.  Follow-up to last visit or study end was 34.2 (21.5, 48) months. Patients were classified into ILAR subtypes at the 6 month visit:  oligoarticular (416, 38%), polyarticular RF negative (235, 21%), polyarticular RF positive (46, 4%), psoriatic (64, 6%), enthesitis related arthritis (ERA) (157, 14%), systemic (sJIA)(76, 7%) and undifferentiated (110, 10%).  Treatment received included intraarticular steroid injections in 46%, DMARDs in 55%, and biologics in 12%.   Almost all patients (92%) achieved AJC=0 during the study period at a median of 7.0 mos (IQR 3.5, 13.3) from diagnosis.  Patients with RF positive polyarthritis were last to reach AJC =0.  Inactive disease was achieved by 81% of subjects at a median of 13.0 mos (IQR 7.7, 21.7) from diagnosis.  Time to first episode of inactive disease was shortest in the oligoarthritis group, and longest in the RF positive polyarthritis group.  Table 1 shows the time to achieve AJC =0 and inactive disease by JIA subtype.    By survival analysis, the probability of disease remission by 4 years of disease was oligoarthritis (41%), polyarticular RF negative (8%), polyarticular RF positive (0%), psoriatic (47%), ERA (28%), sJIA (29%) and undifferentiated (30%). 

Table 1: Disease duration (in months) to achieve outcomes

	AJC = 0		Inactive Disease
	N	Median (IQR)	N	Median (IQR)
Oligoarthritis	412	5.9 (3.3, 10.0)	410	9.6 (6.8, 14.9)
Polyarticular RF negative	235	10.2 (5.0, 16.5)	232	14.9 (10.8, 27.3)
Polyarticular RF positive	46	10.0 (6.7, 20.2)	46	24.2 (13.5, 39.5)
Psoriatic	62	7.2 (4.7, 14.9)	63	12.6 (7.7, 18.1)
Enthesitis Related Arthritis	157	6.8 (3.0, 14.3)	153	16.0 (10.7, 24.5)
Systemic	75	3.6 (2.0, 11.3)	74	13.1 (6.7, 36.4)
Undifferentiated	110	6.4 (3.2, 15.9)	108	14.4 (9.4, 22.7)

Conclusion: Almost all patients achieve an AJC =0, and most attain inactive disease; however, the probability of remission remains low for the polyarticular subtypes.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-research-in-arthritis-in-canadian-children-emphasizing-outcomes-reacch-out-cohort-are-we-achieving-clinically-important-outcomes/