IL6 and arthropathy: Patients with clinically significant arthropathy (n = 22), as defined by an OJS > 4, were older (Online Resource 7B) and had higher IL-6 serum levels (3.6 (1.9–6.1) vs. 1.8 (1.0–3.4) ng/L, median (IQR); P < 0.05) than patients without clinically significant arthropathy (n = 21).