Wang 2005.

Methods	Study design: ITS
Participants	Physicians Clinical speciality: general practice/family medicine Level of training: fully trained Setting/country: outpatient (e.g. ambulatory care provided by hospitals/specialists)/US
Interventions	2‐ PEMs were studied in this report. The ADA guidelines published in January 1998 advocated an LDL cholesterol goal under 100 mg/dL for patients with diabetes.  The second PEM was the third report entitled ATP III published by the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (May 2001) that designated diabetes as a CHD risk equivalent, with the same LDL cholesterol goal of under 100 mg/dL
Outcomes	2 process outcomes: LDL cholesterol reporting for diabetes visits relative to CHD visits (per cent of diabetes visits with LDL cholesterol reported) minus (per cent of CHD visits with LDL cholesterol reported) LDL cholesterol control for diabetes visits relative to CHD visits (per cent of LDL cholesterol reported during diabetes visits) minus (per cent of LDL cholesterol reported during CHD visits)
Notes	We looked at the combined effect of the 2 PEMs because of a lack of data to look at them separately. In this case, the 2 PEMs studied were very similar, and we characterised them as a whole (i.e. 1 PEM)
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent of other changes ‐ ITS	Unclear risk	No information was provided
Shape of Intervention effect pre‐specified ‐ ITS	Unclear risk	Quote, pg. 2942: "The publication of the ADA and ATP III guidelines provides an opportunity to assess the effect of guideline changes on LDL cholesterol reporting and control for diabetes visits"
Intervention unlikely to affect data collection ‐ ITS	Low risk	The interventions (ADA guidelines and ATP III  guidelines) did not affect either the source or the method of data collection
Blinding of outcome assessors (detection bias) ‐ ITS All outcomes	Low risk	The outcome was objective
Incomplete outcome data (attrition bias) ‐ ITS All outcomes	Low risk	Quote, pg. 2942: "we used the National Disease and Therapeutic Index (NDTI) (3), an ongoing survey of U.S. office‐based physicians conducted by IMS Health providing nationally representative diagnostic and treatment data, to analyze the national trends of LDL cholesterol reporting and control for diabetes and CHD visits by year between 1995 and 2004"
Selective reporting (reporting bias) ‐ ITS	Low risk	All relevant outcomes in the methods section were reported in the results section
Other bias ‐ ITS	Low risk	There was no evidence of other risks of bias