Table 2.

All infections requiring hospitalization in 609 patients diagnosed with rheumatoid arthritis (RA) in 1955-1994 compared with 464 patients diagnosed with RA in 1995-2007

	Patients, n		Infections, n		Incidence/100 person-years (all events/person-years)
Infection Type	1955-1994	1995-2007	1955-1994	1995-2007	1955-1994	1995-2007	Rate ratio*	95% confidence interval
Total	290	54	740	178	9.57	6.56	0.69	0.58, 0.80
Bacteremia/septicemia	53	10	60	14	0.78	0.52	0.68	0.36, 1.16
Septic arthritis	20	3	27	3	0.35	0.11	0.36	0.08, 0.92
Osteomyelitis	11	0	13	0	0.17	0.00	0.11	0.00, 0.59
Pneumonia	155	28	240	54	3.10	1.99	0.65	0.47, 0.85
Lower respiratory tract	57	10	89	10	1.15	0.37	0.33	0.16, 0.59
Urosepsis/pyelonephritis	27	4	35	5	0.45	0.18	0.44	0.15, 0.96
Skin/soft tissue	109	21	183	41	2.37	1.51	0.64	0.45, 0.89
Gastrointestinal infections†	26	13	38	34	0.49	1.25	2.55	1.60, 4.04
Intra-abdominal	25	5	26	5	0.34	0.18	0.59	0.20, 1.33
Other	24	8	29	12	0.38	0.44	1.21	0.59, 2.26
Opportunistic Infections‡	3	6	3	11	0.04	0.41	9.35	3.22, 41.4
Clostridium difficile	1	3	1	6	0.01	0.22	12.34	2.84, 176.5

^*Obtained by dividing infection incidence rates in 1995-2007 RA patients by those in 1955-1994 RA patients.

**Any urinary tract infection that required hospitalization was classified as urosepsis/pyelonephritis.

^†includes gastroenteritis, diverticulitis, infective colitis, clostridium difficile, and vancomycin-resistant enterococci

^‡includes clostridium difficile and vancomycin-resistant enterococci

CI = confidence interval; NA = not applicable.