Table 1 Characteristics at start of first tumour necrosis factor (TNF) antagonist treatment in the Swedish ARTIS register cohort of 4167 patients with rheumatoid arthritis (RA) starting treatment with TNF antagonists in 1999–2003, and in the subset thereof who had a pre-treatment hospitalisation with RA

	All anti-TNF 1998–2003	Anti-TNF 1998–2003, also in Inpatient Register RA cohort
Overall	4167 (100%)	2692 (100%)
Sex
Males	1015 (24%)	581 (22%)
Females	3152 (75%)	2111 (78%)
Age at entry (years)
0–49	1343 (32%)	727 (27%)
50–74	2603 (62%)	1778 (66%)
75+	221 (5.3%)	187 (7.0%)
Year of first anti-TNF start
1998–2000	1633 (39%)	1221 (45%)
2001–2002	1390 (33%)	848 (32%
2003	1144 (27%)	623 (23%)
RA duration at start (years)	12.1 (9.7)	15.0 (13.3)
DAS28 at start	5.63 (5.72)	5.74 (5.83)
HAQ at start	1.43 (1.45)	1.57 (1.63)
Year of birth
1900–1919	38 (0.9%)	33 (1.2%)
1920–1939	1203 (29%)	924 (34%)
1940–1959	2133 (52%)	1335 (50%)
1960–1979	754 (18%)	388 (14%)
1980–	39 (0.9%)	12 (0.5%)
Married	2410 (59%)	1636 (61%)

DAS28, Disease Activity Score 28; HAQ, Health Assessment Questionnaire.