Cardiovascular disease (CVD) mortality rates have been declining in the modern era with improved clinical care and better risk factor control. However, CVD remains the leading cause of death in the United States and is projected to affect approximately 45% of the population in the next 15 years. As randomized controlled trials are not always feasible, the use of longitudinal data to identify risk factors and effective treatment for primary and secondary prevention of CVD is essential. The aim of this dissertation was to conduct three studies that assess the risk of second major CVD events after a first CVD event, the effect of moderate alcohol consumption on stroke risk, and the effect of treatment for hypertension using a quasi-experimental design.
In study one, I used data from the Framingham Heart Study to describe the risks of five CVD and mortality outcomes after a first major CVD event. I also assessed how the risk of a second CVD event differs from the risk of a first CVD event. I found that those who have experienced a first CVD event have a higher risk of CVD-related mortality and heart failure as a second CVD event compared with the risk of a first major CVD event. I also found that individuals whose first CVD type was myocardial infarction or heart failure had the highest risk of experiencing heart failure as a second event; those whose first CVD type was a stroke had the highest risk of mortality or a recurrent stroke.
In study two, I used data from the Veterans Affairs Million Veteran Program to estimate the effect of moderate alcohol consumption on the risk of ischemic and hemorrhagic stroke compared with never drinking, and assessed if primarily drinking wine, beer or liquor is associated with a difference in stroke risk compared with drinking a mixture of beverage types. I observed that moderate alcohol consumption was associated with a reduced risk of stroke; however, stratified analyses by age and number of previous hospital visits provided some evidence that healthy survivor bias and residual confounding may have impacted the observed protective effect. I did not observe a difference in strong risk among those who primarily drink wine or beer, and a slight increase in stroke risk in those who preferred liquor, compared with those who have no beverage preference.
In study three, I used Veterans Health Administration electronic health record data and a regression discontinuity design to estimate the effect of eligibility for antihypertensive treatment for patients with stage 1 hypertension, defined using national guidelines, on lowering blood pressure. I found that the blood pressure guidelines were associated with a small increase in antihypertensive treatment initiation and controlled blood pressure within 24 months. I also observed a reduction in blood pressure when estimating the effect of actual treatment among those with hypertension compared with those who were not on treatment.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/44451 |
| Date | 18 May 2022 |
| Creators | Song, Rebecca Jung |
| Contributors | Fox, Matthew P. |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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