Table 3 Numbers of infections and RR (estimated through Cox regression) for hospitalisation with infection during time on first tumour necrosis factor (TNF) antagonist treatment 1999–2003 in the Swedish Inpatient rheumatoid arthritis (RA) cohort, by time since start of TNF antagonist treatment, among 44 946 RA patients of whom 2692 patients started treatment with a first TNF antagonist

	During first TNF antagonist		TNF antagonist naive	RR by time since treatment start*
	No. of events	Crude rate per 100	No of events	Year 1	Year 2	Year 3
Any infection	261	5.4	10 669	1.43 (1.18 to 1.72)	1.15 (0.88 to 1.51)	0.82 (0.62 to 1.08)
Respiratory	111	2.2	6046	1.24 (0.92 to 1.68)	1.45 (1.00 to 2.09)	0.68 (0.44 to 1.05)
Pneumonia	79	1.5	4704	1.11 (0.77 to 1.60)	1.31 (0.86 to 1.93)	0.59 (0.35 to 0.99)
Gastrointestinal	24	0.5	1517	1.03 (0.58 to 1.81)	0.13 (0.02 to 0.91)	0.94 (0.45 to 1.94)
Skin/soft tissue	21	0.4	1004	0.57 (0.21 to 1.57)	1.01 (0.48 to 2.16)	0.82 (0.39 to 1.76)
Joint	25	0.5	652	1.26 (0.66 to 2.40)	0.17 (0.02 to 1.28)	1.42 (0.67 to 2.98)
Septicaemia	36	0.7	1,716	1.07 (0.65 to 1.77)	0.71 (0.33 to 1.55)	0.62 (0.32 to 1.18)

*Cox model stratified for sex, year of birth, county of residence and using calendar time as time scale. Adjusted for marital status, chronic obstructive pulmonary disease, any cardiovascular disease, any pre-treatment infection, diabetes, joint replacements in hip, knee, shoulder and ankle, respectively, total number of days spent in hospital and number of discharges listing RA. All time-varying covariates were assessed as time-dependent variables until 1 year before the outcome.