Can the sum of pooled data from observational studies better evaluate outcome measures for therapies in coronary artery disease?

Randomized control trials (RCTs) are considered the gold standard in the hierarchy of evidence based medicine. Guidelines and recommendations for clinical practice are based on the strength of evidence in this hierarchical tree. This article looks at the weakness of RCTs and variance between large pooled observational data and trial results for some of the historical trials in coronary artery disease. Observational studies can supplement data from resource intensive RCTs. Guidelines for reporting and analysis however need to be rigorous. It further discusses alternate systems of hierarchies as basis for recommendations.