Footnotes

• Contributors All authors contributed to the planning, conduct and reporting of the work described in the article. MDN, CLB and LAF jointly developed the idea for the article. MDN performed literature searches and obtained feedback from key informants. MDN, CLB and LAF analysed and interpreted the data. MDN wrote the first draft of the article; CLB and LAF provided extensive critical revisions on article drafts. MDN is the guarantor and accepts full responsibility for the article. MDN had access to all study data and controlled the decision to publish. Additional contributions: Michael Cirullo provided research assistance. We received valuable feedback on a previous version of this manuscript from Mary Dixon-Woods, Renee Fox, Sandy Schwartz, Robert Aronowitz, Kim Eagle, Allan Detsky and Amir Qaseem.

• Funding This study was supported by a grant to MDN from the National Institute on Aging, Bethesda, MD (grant 1K08AG043548).

• Competing interests LAF has been a volunteer member and chair of ACC/AHA guideline committees from 1996 to the present; no compensation was provided for his work on these guidelines.

• Ethics approval University of Pennsylvania School of Medicine IRB.

• Provenance and peer review Not commissioned; externally peer reviewed.