This site became the new on June 19th. Learn more.
Show more Menu IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu IMPORTANT: Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu
Give us feedback

Compliance in the Physicians' Health Study

This study has been completed.
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: May 25, 2000
Last updated: March 15, 2016
Last verified: May 2000
To evaluate the relationships of compliance in taking aspirin or aspirin placebo with the risk of major cardiovascular endpoints, using data collected in the Physicians' Health Study.

Cardiovascular Diseases Heart Diseases Coronary Disease Myocardial Infarction

Study Type: Observational

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: February 1991
Study Completion Date: January 1993
Detailed Description:


The Physicians' Health Study was a randomized, double-blind placebo-controlled primary prevention trial designed to test whether 325 mg aspirin every other day reduced risks of cardiovascular disease and whether 50 mg beta-carotene on alternate days decreased cancer incidence among 22,071 male U.S. physicians, aged 40-84 years in 1982. Compliance with study pills, the use of non-study aspirin and platelet active drugs, specific side effects of aspirin, the incidence of conditions indicating aspirin use, and study outcomes were assessed at six month intervals during the first year and annually thereafter. The blinded aspirin component of the trial was terminated early and participants were unblinded on January 25, 1988, due to the emergence of a statistically extreme benefit of aspirin on both fatal and nonfatal myocardial infarction, as well as the extraordinarily low cardiovascular mortality rates among study participants.


Separate dose-response relationships were estimated in the aspirin and in the placebo group to determine whether compliance in the placebo group was associated with lower risk, as had been found in some previous trials. Rates of cardiovascular endpoints in the placebo group relative to the aspirin group were adjusted for time-varying compliance with study tablets, and the use of non-study aspirin and platelet active drugs. In addition, baseline characteristics of the population and longitudinal assessment of side-effects and new conditions suggesting aspirin therapy were used as predictors of compliance in taking study pills separately in the aspirin and placebo groups. Similar longitudinal analyses determined predictors of the use of non-study aspirin and platelet active drugs. The analyses were intended to supplement the already published intent-to-treat analyses. They provided observational evidence concerning dose of aspirin and the risks of major cardiovascular endpoints. Examining modification of the aspirin effect in reducing risk of myocardial infarction according to level of compliance aided in the generalizability of results to less motivated populations. Evaluating determinants of good study compliance should be of benefit to future large scale clinical trials.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.


Ages Eligible for Study:   up to 100 Years   (Child, Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

No Contacts or Locations Provided
  More Information

Publications: Identifier: NCT00005404     History of Changes
Other Study ID Numbers: 4321
R03HL046163 ( U.S. NIH Grant/Contract )
Study First Received: May 25, 2000
Last Updated: March 15, 2016

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases
Myocardial Infarction
Coronary Disease
Coronary Artery Disease
Pathologic Processes
Myocardial Ischemia
Vascular Diseases
Arterial Occlusive Diseases processed this record on September 21, 2017