More Heart Guidelines Based on Low Levels of Evidence
Guidelines increasingly make recommendations based on expert opinion, case studies
TUESDAY, Feb. 24 (HealthDay News) -- Many recommendations in guidelines are based on low levels of evidence or expert opinion, according to an article published in the Feb. 25 issue of the Journal of the American Medical Association.
Pierluigi Tricoci, M.D., Ph.D., of Duke University in Durham, N.C., and colleagues assessed practice guidelines generated jointly from the American College of Cardiology and the American Heart Association between 1984 and 2008. This included a total of 53 guidelines encompassing 22 topics, totaling 7,196 recommendations.
The number of recommendations that appeared in guidelines that had at least one revision increased 48 percent (from 1,330 to 1,973 recommendations from the first to the most current version), the researchers report. The majority of this increase was attributed to the incorporation of class II recommendations, which are associated with conflicting evidence or a divergence of opinion. Only 16 percent of the guidelines used recommendations classified as level of evidence A, based on multiple trials or meta-analysis, the authors note. In comparison, nearly half (48 percent) were classified as level of evidence C, solely based on expert opinion, case studies, or standards of care.
"Unless there is evidence of appropriate changes in the guideline process, clinicians and policymakers must reject calls for adherence to guidelines," the authors of an accompanying editorial write. "Physicians would be better off making clinical decisions based on valid primary data."
Several of the study authors report financial relationships with the pharmaceutical industry, and this project was supported by a grant from the Agency for Healthcare Research and Quality.