Clinical features

• valvular heart disease ^b (including mitral valve prolapse) ^b
  
  • which valves are affected ^b
  • severity of disease ^b
  • any recent valvular surgery in the last 2 months ^a
  • any prosthetic valves ^b
• previous rheumatic fever ^b
• previous endocarditis ^b
• intravenous drug use ^b
• any infectious episode in the last 3 months ^b particularly superficial wound infections ^a
• any skin wounds in the last 3 months ^b  

Note:

• Recent dental, surgical or medical procedures do not clearly predict an increased risk of developing infective endocarditis. ^b
  

Why?

Valvular heart disease, valvular surgery or previous endocarditis increases the risk of developing infective endocarditis

Outcome b	Risk Factor	PEER	OR (95% CI)	NNH (95% CI)
infective endocarditis	severe valvular heart disease (mixed or prosthetic valves) independent	0.0050%	131 (6.9 to 2490)	160 (9 to 3400)
	cardiac valvular surgery independent	0.0050%	74.6 (12.5 to 447)	270 (46 to 1700)
	previous episode of endocarditis independent	0.0050%	37.2 (4.4 to 317)	550 (64 to 5900)
	known mitral valve prolapse independent	0.0050%	19.4 (6.4 to 58.4)	1100 (350 to 3700)
	any cardiac valvular abnormality independent	0.0050%	16.7 (7.4 to 37.4)	1300 (550 to 3100)
	rheumatic fever independent	0.0050%	13.4 (4.5 to 39.5)	1600 (520 to 5700)
	infectious episode independent	0.021%	3.9 (2.1 to 7.3)	1600 (760 to 4300)
	skin wound independent	0.021%	3.9 (1.6 to 9.6)	1600 (560 to 7900)
	congenital heart disease independent	0.0050%	6.7 (2.3 to 19.4)	3500 (1100 to 15000)
	heart murmur independent	0.0050%	4.2 (2.0 to 8.9)	6300 (2500 to 20000)
	any dental procedure independent	0.0050%	1.4 (0.7 to 2.7)	50000 (-67000 to 12000)

Prosthetic valves, wound infections, hypoxia and active endocarditis increase the risk of infective endocarditis following valve surgery

Patient	Prognostic Factor	Outcome	CER	RR (95% CI)	NNF+ (95% CI)
prosthetic valve replacement in last 2 months a	superficial wound infection independent	infective endocarditis at 8 years	1.3% (0.7% to 2.0%)	3.5	9
	preoperative hypoxia (pO2 < 80 mmHg) independent	infective endocarditis at 8 years	1.3% (0.7% to 2.0%)	7.9	11
	active endocarditis independent	infective endocarditis at 8 years	1.3% (0.7% to 2.0%)	6.8	13
	resident as primary surgeon independent	infective endocarditis at 8 years	1.3% (0.7% to 2.0%)	3.2	34
	preoperative valve lesion independent	infective endocarditis at 8 years	1.3% (0.7% to 2.0%)