Table 1.

Summary of the main studies focusing on encapsulated bacterial infections in inflammatory bowel disease.

References	Country	Study design	Patients, n	Infection type	Infection risk
Long et al. (21)	US	Retrospective cohort study Nested case-control study	50,932 CD 56,403 UC 1,269 unspecified IBD 434,416 Hc	Pneumonia	HR 1.71, 95% CI 1.62–1.80 (CD) HR 1.41, 95% CI 1.34–1.48 (UC)
Kantsø et al. (7)	Denmark	Population-based cohort study	22,098 CD 52,058 UC 1,482,363 Hc	IPD	HR 1.99; 95% CI, 1.59–2.49 (CD) HR, 1.46; 95% CI, 1.25–1.69 (UC)
Stobaugh et al. (22)	US	Cross-sectional study Nationwide inpatient sample	48,087,002 inpatient discharge visits	Pneumonia S. pneumoniae H. influenzae	HR 1.08; 95% CI, 0.99–1.17 (CD) HR 0.93; 95% CI, 0.82–1.06 (UC) HR 1.28; 95% CI, 1.06–1.54 (CD) HR 1.42; 95% CI, 1.13–1.79 (UC)

CD, Crohn disease; Hc, Health controls; IPD invasive pneumococcal infection; UC, ulcerative colitis.