gms | German Medical Science

Background: Medical knowledge is estimated to double every two to nineteen years. Sixteen percent of highly cited research is subsequently contradicted. It is unknown how often these changes occur in areas affecting clinical decision-making.

Objectives: To measure the pace of change in diagnosis and treatment overviews derived from the best evidence and guidelines.

Methods: Two hundred DynaMed topics will be evaluated. Overview sections (integrating the best evidence and guidance) will be analyzed for changes over 1-2 years. We will classify each change as resulting from new evidence or guidance (the primary outcome for this analysis) or from user feedback or quality improvement.

Results: As of February 10, 2012 the management overviews of fourteen topics have been evaluated for a period of 0.84 to 1.73 years. Eleven topics (79%) were changed based on new evidence and eleven (79%) were changed based on new guidelines. Among 828 lines in these topic overviews, 204 (25%) were modified and 95 (11%) were deleted; 181 new lines (22%) were added. Of the 480 changes, 272 (57%) were due to new evidence or guidelines. The annualized rate of change of overview content due to new evidence or guidelines was 24.7%. Interim results (about 100 topics) will be presented.

Discussion: Twenty-five percent of core information guiding clinical practice is changed within one year based on new evidence or guidelines.

Implications for guideline developers/users: Quantifying the rate of change in practice-guiding medical knowledge can guide how often guidelines need to be updated.