In Reply: In response to Dr Beri, we excluded patients with prior revascularization because we were interested in studying the natural history of treating de novo disease, not the treatment of graft disease or a restenosis. We made no direct comparison of the outcomes of bare-metal stents vs drug-eluting stents because we believed such an analysis would be confounded. Bias could arise for 2 reasons. First, if patients with better unmeasured health are treated with drug-eluting stents, the apparent benefits of drug-eluting stents would be biased upward. Second, if higher-quality hospitals (for example, teaching hospitals) adopted drug-eluting stents more rapidly, the apparent benefits of drug-eluting stents would again be overstated.
Malenka DJ, Skinner JS, Lucas FL. Outcomes in the Era of Bare-Metal Stents vs the Era of Drug-Eluting Stents—Reply. JAMA. 2009;301(1):33-34. doi:10.1001/jama.2008.900