Effects of routine individual feedback over nine years on general practitioners' requests for tests

Feedback to general practitioners about the diagnostic tests they request reduces the number of requests. 1 This effect disappears, however, soon after feedback is stopped. 2 Most studies have been short, so data on the long term effects of feedback are lacking. 3 The Diagnostic Coordinating Centre Maastricht has provided feedback continuously since 1985, resulting in a more rational use of tests and fewer requests. 4 5 We report the effects of nine years of feedback. For these common tests in our region we also compared the trend for tests that were advised against but had a recommended alternative (measurement of urea, thyroxine, free thyroxine, and triiodothyronine concentrations; Rose-Waaler and latex fixation tests) with that for tests that were advised against but had no recommended alternative (haemoglobin concentration, packed cell volume, differential count, erythrocyte sedimentation rate, leucocyte count, erythrocyte count, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase).