Clinical trials and "real-world" medicine

Trial evidence best informs real-world medicine when it is relevant to the clinical problem

Controlled clinical trials provide the most reliable evidence of whether treatments are effective, particularly when the effects of treatment are moderate. Without such trials, ineffective treatments or, even worse, harmful interventions may be accepted in medical practice. Yet medical practice is often not based on clinical trial evidence, because the evidence is considered not relevant or does not exist. Real-world medicine must not only consider the effectiveness of specific treatments, but must do so in the context of patients who have multiple problems and who are often already receiving many different treatments in a setting different from that tested in the trial.1