RT Journal
A1 Costagliola D, Hernán MA
T1 Β-blocker use for patients with or at risk for coronary artery disease
JF JAMA
JO JAMA
YR 2013
FD February 6
VO 309
IS 5
SP 438
OP 438
DO 10.1001/jama.2012.128862
UL http://dx.doi.org/10.1001/jama.2012.128862
AB 
To the Editor: Observational studies are increasingly being used for comparative effectiveness research. To be relevant for clinical practice, observational studies need to mimic RCTs as closely as possible. The study by Dr Bangalore and colleagues1 illustrates several ways in which an observational study may unnecessarily differ from an RCT. The authors wanted to estimate the effect of β-blocker use on cardiovascular disease among patients with prior MI, those with prior CAD but without MI, and those with CAD risk factors.