Observational studies of treatment effectiveness: some cautions.
Laupacis
Andreas
A
Mamdani
Muhammad
M
D003327:Coronary Disease / Q000401:mortality / Q000517:prevention & control*; D017052:Hospital Mortality; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use*; D019370:Observation; D055502:Secondary Prevention; D015983:Selection Bias; D016896:Treatment Outcome
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors