Randomised controlled trials (RCTs) that assessed the effects of providing feedback on diabetes care to general practitioners on the quality of care in patients with Type 2 diabetes were eligible for inclusion in the review. Feedback was defined as "any summary of clinical performance of health care over a specified period of time". Electronic feedback was similarly defined, but delivered to the end user via computer.
Most included studies assessed printed feedback; only 20% of studies assessed electronic feedback; 10% assessed both printed and electronic feedback. Included studies were published between 1994 and 2005 (most after 2000). Most studies assessed patient-specific feedback and 20% assessed aggregated feedback for individual general practitioners or general practitioner practices. In just over half of the studies feedback was the only intervention; in the other studies feedback was part of a larger multicomponent intervention. Regular feedback was compared to other interventions and combined feedback was compared with other support interventions.
Single studies compared combined feedback with outreach visits, feedback with a face-to-face evaluation with an endocrinologist and feedback with written patient feedback in the waiting room plus a computer reminder.
Most studies were conducted in USA; others were in Scandinavia, New Zealand and The Netherlands. Trial duration ranged from two months to six years (median duration 12 months). All studies used process measures that formed part of routine diabetes management (such as blood glucose and serum cholesterol). Other outcomes included composite measures such as compliance rates and compliance to diabetes guidelines. Data were collected via chart review, encounter forms filled in by participating general practitioners, databases or by combinations of these methods.
Studies were primarily assessed by one reviewer. Any uncertainties were discussed with the review team members.