A thoughtful compelling argument against the use of infectious endocarditis (IE) prophylaxis is presented by Dr Morris, and he correctly suggests that definitive data from a randomized controlled clinical trial are not likely to be forthcoming.
The crux of this debate centers on how we make decisions in the absence of definitive data. In each of the studies described by Dr Morris, a potential benefit of IE cannot be definitively excluded. For example, in the 2 studies cited as evidence against IE, prophylactic antibiotics seem to decrease the risk of IE, with a protective effect ranging from 20% to 49%.1,2 Although not statistically significant, the results are not irrelevant, particularly when considered along with 2 studies that reported a statistically significant protective effect of IE prophylaxis.3,4 In addition, it may not be reasonable to expect 100% effectiveness, particularly in nonrandomized, community-based, retrospective studies that may not have detailed antibiotic dosing or procedure information.
Seto TB. Rebuttal. Arch Intern Med. 2007;167(4):333. doi:10.1001/archinte.167.4.333