Predicting the Benefits of Percutaneous Coronary Intervention on 1-Year Angina and Quality of Life in Stable Ischemic Heart Disease
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BACKGROUND: Percutaneous coronary intervention (PCI) is a therapy to reduce angina and improve quality of life in patients with stable ischemic heart disease. However, it is unclear whether the quality of life after PCI is more dependent on the PCI or other patient-related factors. To address this question, we created models to predict angina and quality of life 1 year after PCI and medical therapy. METHODS AND RESULTS: Using data from the 2287 stable ischemic heart disease patients randomized in the COURAGE trial (Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation) to PCI plus optimal medical therapy (OMT) versus OMT alone, we built prediction models for 1-year Seattle Angina Questionnaire angina frequency, physical limitation, and quality of life scores, both as continuous outcomes and categorized by clinically desirable states, using multivariable techniques. Although most patients improved regardless of treatment, marked variability was observed in Seattle Angina Questionnaire scores 1 year after randomization. Adding PCI conferred a greater mean improvement (about 2 points) in Seattle Angina Questionnaire scores that were not affected by patient characteristics (P values for all interactions >0.05). The proportion of patients free of angina or having very good/excellent physical limitation (physical function) or quality of life at 1 year was 57%, 58%, 66% with PCI+OMT and 50%, 55%, 59% with OMT alone group, respectively. However, other characteristics, such as baseline symptoms, age, diabetes mellitus, and the magnitude of myocardium subtended by narrowed coronary arteries were as, or more, important than revascularization in predicting symptoms (partial R2=0.07 versus 0.29, 0.03 versus 0.22, and 0.05 versus 0.24 in the domain of angina frequency, physical limitation, and quality of life, respectively). There was modest/good discrimination of the models (C statistic=0.72-0.82) and excellent calibration (coefficients of determination for predicted versus observed deciles=0.83-0.97). CONCLUSIONS: The health status outcomes of stable ischemic heart disease patients treated by OMT+PCI versus OMT alone can be predicted with modest accuracy. Angina and quality of life at 1 year is improved by PCI but is more strongly associated with other patient characteristics. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00007657.
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