Inside guidelines: comparative analysis of recommendations and evidence in diabetes guidelines from 13 countries.

OBJECTIVE To compare guidelines on diabetes from different countries in order to examine whether differences in recommendations could be explained by use of different research evidence. RESEARCH DESIGN AND METHODS We analyzed 15 clinical guidelines on type 2 diabetes from 13 countries using qualitative methods to compare the recommendations and bibliometric methods to measure the extent of overlap in citations used by different guidelines. A further qualitative analysis of recommendations and cited evidence for two specific issues in diabetes care explored the apparent discrepancy between recommendations and evidence. RESULTS The recommendations made in the guidelines were in agreement about the general management of type 2 diabetes, with some important differences in treatment details. There was little overlap in evidence cited by the guidelines, with 18% (185/1,033) of citations shared with any other guideline, and only 10 studies (1%) appearing in six or more guidelines. The measurable overlap in evidence between guidelines increases if multiple publications from the same study and the use of reviews are taken into account. Research originating from the U.S. predominated (40% of citations); however, nearly all (11/12) guidelines were significantly more likely to cite evidence originating from their own countries. CONCLUSIONS Despite the variation in cited evidence and preferential citation of evidence from a guideline's country of origin, we found a high degree of international consensus in recommendations made for the clinical care of type 2 diabetes. The influence of professional bodies such as the American Diabetes Association may be an important factor in explaining international consensus. Globalization of recommended management of diabetes is not a simple consequence of the globalization of research evidence.