These findings have far reaching implications for how the current medical information system transmits new research results from academia to practitioners.
Thirty five reviews on treatment of type 2 diabetes were analysed to evaluate how experts represented the results of the United Kingdom prospective diabetes study (UKPDS).
Only six of the reviews included the finding that tight blood sugar control had no effect on overall or diabetes-related mortality. Just seven mentioned that giving the drug metformin was associated with decreased mortality.
Almost half (17) of the reviews did not mention the need for blood pressure control, while only five pointed out that diabetic patients with high blood pressure benefit more from blood pressure control than blood sugar control.
The current system of transmitting new research to clinicians by means of reviews is less than optimal, at least for new important research in type 2 diabetes, say the authors. Clinicians relying on these information sources for accurate clinical information may be misled, they conclude.
The faults of expert reviews are already well known, argues David Fitzmaurice in an accompanying commentary.
He agrees that review articles, particularly those written by specialists, tend to be of dubious value, but say that most UK primary care physicians are aware of the key messages in the UKPDS study. "We should perhaps question why these expert reviews continue to be published, given both their lack of rigour and their apparent lack of influence," he concludes.