Objective: An outpatient-based scoring system was developed for at-risk patients with coronary artery disease based on data derived from the clinical history and noninvasive testing results for the prediction of an adverse event, the development of risk subsets, and the evaluation of the appropriateness of utilization patterns in an ambulatory care patient population.
Method: This was a hospital-based cohort study. From a population of 3,795 consecutively tested patients, 872 with suspected coronary artery disease were enrolled from a midwestern university tertiary medical center from 1988 to 1989.
Results: Multivariable Cox modeling was used to develop scoring weights with scores ranging from -1.6 to 8.5 points. Significant multivariable disease predictors of cardiac death or myocardial infarction were use of nitroglycerin or insulin, ST-T wave changes, female gender, left ventricular hypertrophy, and a reversible thallium 201 defect. Receiver operating characteristics curves by use of the hazard score were comparable by gender. A probability threshold of .30 for cardiac death or myocardial infarction yielded a cut point of acceptable sensitivity and specificity for prompting medical management decisions. Below this threshold, the rate of follow-up diagnostic testing was 16.9% for women and 57.8% for men (p=.00001). Above this threshold, the rate of follow-up diagnostic testing was 40.6% for women and 64.3% for men (p= .04).
Conclusion: Use of cardiac diagnostic services and cardiac event-free survival varies by gender in patients screened by noninvasive testing. For men at low risk of cardiac death or myocardial infarction, a statistically greater use of follow-up diagnostic testing was reported, thus reflecting more aggressive treatment and overuse of services for men as compared with women.