Seeing what you want to see in randomised controlled trials: Versions and perversions of UKPDS data

Randomised trials are subject to interpretation bias as shown by the example of the UK prospective diabetes study. The UK prospective diabetes study shows no benefit on macrovascular end points in patients with type 2 diabetes treated with sulphonylureas or insulin over 10 years. The study shows a clinically important benefit on macrovascular end points from metformin in patients with type 2 diabetes that seems somewhat independent of the drug's ability to lower blood glucose concentrations. Nevertheless, many authors, journal editors, and the wider scientific community interpreted the study as providing evidence of the benefit of intensive glucose control. Journal editors should be aware of this important potentialbias and encourage authors to present their results initially with, a minimum of discussion so as to invite a range of comments and perspectives from readers.