Presence of autoantibodies in “seronegative” rheumatoid arthritis associates with classical risk factors and high disease activity

Table 4 Disease activity during 5-years follow-up, in relation to autoantibody status

RA subset^a		0 m	3 m	6 m	12 m	24 m	36 m	48 m	60 m
Seronegative	DAS28	5.10	3.49	3.25	2.72	2.33	2.14	1.96	2.2.11
Seronegative	n	163	138	139	154	148	73	47	103
Ab+	DAS28	5.37	3.59	3.34	2.80	2.68	2.63	2.97	2.02
Ab+	n	123	110	107	119	104	56	35	62
ACPA+	DAS28	5.34	3.63	3.41	2.94	2.71	2.99	3.66	2.20
ACPA+	n	87	77	79	84	75	40	21	41
RF+	DAS28	5.50	3.67	3.49	2.49	2.27	2.61	3.17	1.88
RF+	n	27	23	23	26	24	13	8	12
Carb+	DAS18	5.50	3.30	3.35	2.77	2.66	2.13	2.20	1.78
Carb+	n	43	38	33	40	33	16	14	24
ACPA+/Carb−	DAS28	5.15	3.66	3.44	3.01	2.76	3.23	3.69	2.37
ACPA+/Carb−	n	68	61	64	67	60	33	16	32
ACPA−/Carb+	DAS28	5.57	3.14	3.30	2.75	2.74	1.89	1.91	1.71
ACPA−/Carb+	n	24	22	18	23	18	9	9	15
Seropositive	DAS28	5.08	3.67	3.25	3.02	2.71	2.94	2.87	2.75
Seropositive	n	747	650	595	719	685	444	315	522

^aAll RA subsets (with the exception of seropositive RA) are anti-CCP2 IgG−/IgM RF−; Ab+ = ACPA+, and/or IgA RF+, and/or IgG RF+, and/or anti-CarP+; seropositive = anti-CCP2 IgG+ and/or IgM RF+. Median DAS28-CRP values are shown for each RA subset (significantly higher DAS28-CRP compared to seronegative RA in bold). N = number of patients in each subset at each time point. 0 m = baseline; 3–60 m = 3 months to 60 months follow-up period

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