Biomedical subjects

Pamela Hartigan

Publications and source records attributed to Pamela Hartigan.

5 recordsLinked to original sources

PubMed2006

Economics methods in the Clinical Outcomes Utilizing percutaneous coronary Revascularization and Aggressive Guideline-driven drug Evaluation (COURAGE) trial.

Percutaneous coronary intervention (PCI) remains a major therapeutic option for the treatment of chronic coronary artery disease. In the COURAGE trial, 2287 patients with chronic coronary disease were randomized between PCI with medical management and medical management alone. Embedded within the COURAGE trial is a detailed economic analysis being conducted in three health care systems: the US Veterans Administration (VA), Canada, and the US non-VA. Resource use and costs are being collected for each system and overall. Survival is assessed internally in the trial with mean follow-up of 4.5 years. Long-term mean survival will be estimated by projecting survival beyond the trial period by extrapolating the in-trial hazard rates. Utility is being assessed at baseline and at 1, 3, and 6 months and annually thereafter, using a computer-administered standard gamble. Quality-adjusted life years are calculated by multiplying survival by utility. The incremental cost-effectiveness ratio of PCI will be defined as the additional cost of PCI divided by the gain in life years and quality-adjusted life years. The 95% confidence regions of efficacy and costs will be determined by bootstrap over a range of acceptability thresholds, which will then be displayed in the cost-effectiveness plane and as a cost-effectiveness acceptability curve. A multilevel regression model will assess cost-effectiveness from a net benefit perspective. These approaches should provide the most detailed assessment available of the cost-effectiveness of PCI for coronary artery disease.

Angioplasty, Balloon, Coronary↗

PubMed2006

Gated myocardial perfusion single photon emission computed tomography in the clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial, Veterans Administration Cooperative study no. 424.

BACKGROUND: Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial. METHODS AND RESULTS: The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization patients. Substudy 2 (n = 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization in reducing patients' ischemic burdens. CONCLUSIONS: The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology. We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based management of patients with stable coronary disease.

Algorithms↗

PubMed2004

Design and statistical issues in the homocysteinemia in kidney and end stage renal disease (HOST) study.

The Homocysteine Study (HOST) Veterans Affairs Cooperative Studies Program No. 453, is a prospective, randomized, two arm, double blind study of patients with end stage renal disease (ESRD) or advanced chronic kidney disease (ACKD, defined as an estimated creatinine clearance of 30 ml/min or less). Its primary objective is to determine whether administration of high doses of three vitamins, folic acid, vitamin B6 and vitamin B12, to lower the high plasma homocysteine levels, will reduce all cause mortality. The secondary objectives are to examine whether the treatment lowers the incidence of myocardial infarction, stroke, amputation of a lower extremity, a composite of death and the foregoing three events, the plasma homocysteine level, and, in ESRD patients undergoing hemodialysis, thrombosis of the vascular access. A unique feature of this trial is that after initial evaluation at enrollment and one return visit the follow up is exclusively by phone (or, if necessary, by mail). The subject is contacted every three months throughout the duration of the study from a central location. The study drug is shipped to the patient from a central location rather supplied locally. In a two year enrollment period, 2006 patients are to be enrolled. The duration of the observation period is four to six years. Data will be stored and analyzed at a coordinating center. The study design has the power to detect a reduction in all cause mortality rate of 17%. Issues related to the unique features of the design of this study are discussed.

Adult↗

PubMed2002

Analysis of randomized controlled trials.

Although the sophistication and flexibility of the statistical technology available to the data analyst have increased, some durable, simple principles remain valid. Hypothesis-driven analyses, which were anticipated and specified in the protocol, must still be kept separate and privileged relative to the important, but risky data mining made possible by modern computers. Analyses that have a firm basis in the randomization are interpreted more easily than those that rely heavily on statistical models. Outcomes--such as quality of life, symptoms, and behaviors--that require the cooperation of subjects to be measured will come to be more and more important as trials move away from mortality as the main outcome. Inevitably, such trials will have to deal with more missing data, especially because of dropout and noncompliance. There are fundamental limits on the ability of statistical methods to compensate for such problems, so they must be considered when studies are designed. Finally, it must be emphasized that the availability of software is not a substitute for experience and statistical expertise.

Data Interpretation, Statistical↗

PubMedDate not supplied

The synergistic effect of heart disease and diabetes on self-management, symptoms, and health status.

BACKGROUND: Coronary heart disease (CHD) and diabetes may have synergistic effects on symptoms, self-management, and general and cardiac-specific health status. PURPOSE: We compared symptom distress, self-management difficulties, and general and cardiac-specific health status in patients with CHD by the presence and severity of diabetes. METHODS: We performed a cross-sectional study of 1013 patients enrolled in the COURAGE trial, with the use of clinical data, the Symptom Distress Scale, the Self-Management Difficulties Scale, the Short-Form 36, and the Seattle Angina Questionnaire. RESULTS: Patients with diabetes and greater severity of diabetes had worse findings in symptom distress, self-management difficulties, and general and cardiac-specific health status than patients without diabetes. CONCLUSIONS: A robust effect of diabetes on symptom distress and self-management difficulties was found in patients with CHD. The results from the Seattle Angina Questionnaire illustrate difficulty in attributing physical limitations to specific symptoms or conditions, and show the experience of comorbid conditions to be synergistic. Clinicians' understanding of this synergy and integration of condition-specific care with general treatment and self-management practices are needed.

Adult↗