Abstract 260: Components of Change Processes of Quality of Life among Stable Coronary Patients with or without Percutaneous Coronary Intervention

Background: Percutaneous coronary intervention (PCI) plus intensive pharmacologic and lifestyle intervention (optimal medical therapy, OMT) to OMT alone was compared in reducing the risk of cardiovascular events in a total of 2,287 patients with stable coronary disease in the COURAGE trial, in which health related quality of life data were measured repeatedly over time for a median of 4.6 years. We examined components of changes in angina-related quality of life over time. Methods: Angina-specific health status was assessed with the Seattle Angina Questionnaire (SAQ). Scores range from 0 to 100; higher scores indicate better health status. Linear piece-wise latent growth curve modeling was conducted to reveal the components of process and risk factors of SAQ score changes over time. Results: For each domain the change process can be divided into two components: a process of improvement from baseline to 6 or 12 months during which the scores significantly increase with a steep upward trajectory till reaching the maximum score value; and followed by a process of stabilization during which the scores kept stable or in a downward slope until the end of the follow-up. Patients in both PCI and OMT alone groups experienced significant increase on SAQ scores over time in each domain. PCI had significant impact in the process of improvement: patients with PCI had about 0.603 (SE=0.193, p-value=0.002) and 0.442(SE=0.22, p-value =0.044) points increase per month in scores in the domains of physical limitation and angina frequency, respectively; the benefit of PCI decreased in the process of stabilization until it disappeared so that the scores in both groups were eventually similar (Table 1). The important risk factors of change in SAQ scores were the use of long-acting nitrates at randomization, the Charlson comorbidity index, and several additional factors that differed by domain. Conclusions: Mechanism and processes of change in angina-related quality of life and health status were significantly related to the impact of adding PCI to OMT. Piece-wise growth curve modeling can be used to capture advantages of PCI over OMT and identify patient characteristics associated with subsequent measures of angina.