Do guidelines for the diagnosis and monitoring of diabetes mellitus fulfill the criteria of evidence-based guideline development?

BACKGROUND: Although the methodological quality of therapeutic guidelines (GLs) has been criticized, little is known regarding the quality of GLs that make diagnostic recommendations. Therefore, we assessed the methodological quality of GLs providing diagnostic recommendations for managing diabetes mellitus (DM) and explored several reasons for differences in quality across these GLs.
METHODS: After systematic searches of published and electronic resources dated between 1999 and 2007, 26 DM GLs, published in English, were selected and scored for methodological quality using the AGREE Instrument. Subgroup analyses were performed based on the source, scope, length, origin, and date and type of publication of GLs. Using a checklist, we collected laboratory-specific items within GLs thought to be important for interpretation of test results.
RESULTS: The 26 diagnostic GLs had significant shortcomings in methodological quality according to the AGREE criteria. GLs from agencies that had clear procedures for GL development, were longer than 50 pages, or were published in electronic databases were of higher quality. Diagnostic GLs contained more preanalytical or analytical information than combined (i.e., diagnostic and therapeutic) recommendations, but the overall quality was not significantly different. The quality of GLs did not show much improvement over the time period investigated.
CONCLUSIONS: The methodological shortcomings of diagnostic GLs in DM raise questions regarding the validity of recommendations in these documents that may affect their implementation in practice. Our results suggest the need for standardization of GL terminology and for higher-quality, systematically developed recommendations based on explicit guideline development and reporting standards in laboratory medicine.