Table 3. Risk ratio of Rheumatoid Factor, Anti-cyclic citrullinated peptide antibodies and sIL-15 levels associated with a higher mean disease activity or need for intensive treatment during the follow-up.

	Mean DAS28		Intensive DMARD treatment
	Risk ratio [95% CI]	p	Risk ratio [95% CI]	p
Rheumatoid Factor +	1.13 [0.63–2.05]	n.s.	1.26 [0.78–2.04]	n.s.
ACPA +	1.57 [0.92–2.67]	n.s.	0.91 [0.56–1.48]	n.s.
sIL-15>20 pg/ml	0.92 [0.66–1.30]	n.s.	2.38 [1.54–3.69]	<0.001
Female gender	2.68 [1.05–6.81]	0.039	-	n.s.
Age at DO: <40 y-o	Ref.	-	-	n.i.
40–55	1.60 [0.47–5.44]	n.s.	-	n.i.
55–70	3.37 [1.07–10.60]	0.038	-	n.i.
>70	6.50 [2.18–19.39]	0.001	-	n.i.

DAS28: 28-joint count Disease Activity Score. DMARD: disease modifying anti-rheumatic drugs. CI: confidence interval. ACPA: anti-cyclic citrullinated peptide antibodies; n.s.: not significant; n.i.: not included. DO: disease onset. Ref.: reference variable.