Table 2.

Crude incidence rates, incidence rate ratio, and adjusted relative rate of oral streptococcal infective endocarditis according to period of exposure, in participants included in cohort study, 2008-14

Variables	No of participants	No of procedures	Person years	No of cases of oral streptococcal IE	Crude incidence rate of oral streptococcal IE (95% CI)	Crude incidence rate ratio (95% CI)	Adjusted relative rate* (95% CI)	P value
Non-exposed	138 846		248 544	235	94.6 (82.5 to 106.6)	1.00	1.00
Invasive dental procedure period:
Total	33 181	103 463	11 811	14	118.5 (56.4 to 180.6)	1.25 (0.73 to 2.00)	1.25 (0.82 to 1.82)†	0.26
Without antibiotic prophylaxis	21 471	51 183	6688	10	149.5 (56.8 to 242.2)	1.58 (0.76 to 2.87)	1.57 (0.90 to 2.53)	0.08
With antibiotic prophylaxis	18 863	52 280	5123	4	78.1 (1.6 to 154.6)	0.83 (0.24 to 1.99)	0.83 (0.33 to 1.69)	0.65
Non-invasive dental procedure period:
Total	53 443	293 152	24 679	18	72.9 (39.2 to 106.6)	0.77 (0.48 to 1.18)	0.80 (0.56 to 1.12)†	0.22
Without antibiotic prophylaxis	47 829	217 767	20 131	13	64.6 (29.5 to 99.7)	0.68 (0.36 to 1.16)	0.70 (0.43 to 1.08)	0.13
With antibiotic prophylaxis	19 428	75 385	4548	5	109.9 (13.6 to 206.3)	1.16 (0.40 to 2.59)	1.27 (0.56 to 2.42)	0.51

IE=infective endocarditis.

*Adjusted for sex, age, presence of implantable cardioverter defibrillator or pacemaker, diabetes, intravenous drug use, dialysis dependence.

†Interaction test between invasive and non-invasive dental procedures z score=1.80 (0.485/0.270; P=0.07).