Dissertation Title: "Identifying High-Value Lifestyle Interventions for Cardiovascular Disease Prevention"
This dissertation evaluates lifestyle strategies for the management of cardiovascular risk factors and prevention of cardiovascular disease (CVD). In Chapter 1, I systematically review and summarize the evidence of the effect of yoga, a popular mind-body practice, on cardiovascular disease and metabolic syndrome risk factors. I perform a narrative systematic review and a random-effects meta-analysis of randomized controlled trials (RCTs) of posture-based yoga practice. I find that yoga showed significant improvement in a variety of risk factors for CVD and metabolic syndrome, including body mass index, systolic blood pressure, and total cholesterol when compared to no or minimal intervention control groups. When compared to active exercise controls, yoga produced similar reductions in risk factors levels. Promising evidence supports yoga’s role in improving cardio-metabolic health. Findings are limited, however, by small trial sample sizes, heterogeneity, and moderate RCT quality.
In Chapter 2, I evaluate the comparative effectiveness of four different lifestyle strategies for reducing 10-year CVD risk. I use published literature on risk factor reductions associated with group therapy for smoking cessation, Mediterranean diet, aerobic exercise (walking), and yoga together with the Pooled Cohort risk algorithms to calculate a personalized optimal strategy for risk reduction based on different patient profiles. I find that for smokers, successful smoking cessation is an optimal strategy for reducing risk whereas for non-smokers or for smokers who do not quit successfully, stress reduction through yoga produces the greatest risk reductions.
In Chapter 3, I examine the cost-effectiveness of aerobic exercise and yoga compared to current medical practice for primary prevention of CVD in US adults. I use a subset of RCTs from Chapter 1, along with published literature on utilities, costs, and other parameters as inputs into a validated CVD microsimulation model. I calculate the cost per quality-adjusted life year ($/QALY) of aerobic exercise and yoga from the societal and healthcare perspective. Results suggest that from the societal perspective, neither intervention is cost-effective using a threshold of $100,000/QALY due to high patient time costs; when the healthcare perspective is taken or when the activities are reimbursed and improvements in quality of life are taken into account, then the activities can be cost-effective. Future research can explore patient preference, adherence, and utility gains from physical activity.