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Gross CP, Steiner CA, Bass EB, Powe NR. Relation Between Prepublication Release of Clinical Trial Results and the Practice of Carotid Endarterectomy. JAMA. 2000;284(22):2886–2893. doi:10.1001/jama.284.22.2886
Author Affiliations: Primary Care Section, Yale University School of Medicine, New Haven, Conn (Dr Gross); Division of General Internal Medicine (Drs Steiner, Bass, and Powe); Welch Center for Prevention, Epidemiology, and Clinical Research (Dr Powe), Department of Health Policy and Management (Drs Bass and Powe), and Department of Epidemiology (Dr Powe), Johns Hopkins Medical Institutions, Baltimore; and Center for Organization and Delivery Studies, Agency for Healthcare Research and Quality, Rockville (Dr Steiner), Md.
Context Little is known about how clinical practice is affected by disseminating
results of clinical trials prior to publication in peer-reviewed journals.
Objective To determine whether prepublication release of carotid endarterectomy
(CEA) trial results via National Institutes of Health Clinical Alerts was
associated with prompt changes in patient care that were consistent with the
new medical evidence.
Design, Setting, and Patients Longitudinal data series analysis using acute care hospital discharge
data from the Healthcare Cost and Utilization Project for patients who had
CEA performed in acute care hospitals in 7 states (New York, California, Pennsylvania,
Florida, Colorado, Illinois, and Wisconsin). The trials were the North American
Symptomatic Carotid Endarterectomy Trial (NASCET clinical alert released February
1991) and the Asymptomatic Carotid Atherosclerosis Study (ACAS clinical alert
released September 1994).
Main Outcome Measure Carotid endarterectomy rate during each month from 1989 (2 years before
the NASCET clinical alert) to 1996 (2 years after the ACAS clinical alert),
adjusted for age and sex. Because both trials were limited to patients 80
years or younger in hospitals with low mortality, we also stratified CEA rates
by patient age and hospital mortality rate.
Results From 1989 through 1996, 272,849 CEAs were performed in the acute care
hospitals in these 7 states, with the annual number increasing from 22,300
to 51,495. After the NASCET clinical alert, the adjusted CEA rate increased
3.4% per month (95% confidence interval [CI], 1.6%-5.3%) during the following
6 months and then increased 0.5% per month (95% CI, 0.2%-0.8%; P<.04) after journal publication of the NASCET study. After the
ACAS clinical alert, the CEA rate increased 7.3% per month (95% CI, 6.0%-8.5%)
during the following 7 months and then decreased by 0.44% per month (95% CI, −0.86%
to −0.0002%; P<.04) after journal publication
of the ACAS study. After the ACAS clinical alert, the CEA rate increased more
in patients aged 80 years or older than in younger patients; whereas, after
journal publication of ACAS, the CEA rate decreased more rapidly in the older
population. The overall proportion of CEAs performed in low-mortality hospitals
did not change substantially after release of the clinical alerts or after
Conclusion In this study, prepublication dissemination of CEA trial results with
clinical alerts was associated with prompt and substantial changes in medical
practice, but the observed changes suggest that the results were extrapolated
to patients and settings not directly supported by the trials.
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