You have to decide whether the patients in this trial were sufficiently similar to your own patients.

Very often randomised controlled trials will recruit patients because they have high outcome rates and try to generalise these results to elsewhere.

For instance, trialling lipid lowering drugs to see if they reduce myocardial infarction in the west of Scotland makes a lot of sense. There will be a lot of myocardial infarctions so the trial can be smaller (and cheaper).

Ask yourself whether the controls were similar to the way you would treat your own patients.