Systemic Lupus Erythematosus (SLE), a prototypic multi-organ autoimmune disease, is associated with a dramatically increased risk of coronary artery disease (CAD) manifesting as angina, myocardial infarction and sudden cardiac death. Traditional cardiac risk factors such as hypertension and hypercholesterolemia, measured at baseline in accordance with the Framingham model, only partially account for the increased risk of CAD in SLE. In this thesis, I have shown that blood pressure (BP), lipids and novel risk factors such as the inflammatory marker high-sensitivity C-reactive protein (hsCRP), take a dynamic course in SLE, with more than half of the variance in serial measurements over time occurring within rather than between individuals. This variability is due to changes in disease activity, treatment, accrual of other cardiac risk factors, and complications such as infection. I have demonstrated that by capturing cumulative exposure over time, ‘summary measures’ such as arithmetic mean and time-adjusted mean (AM) are better able to quantify CAD risk in patients with SLE than single-point-in-time measurements of risk factors. By incorporating ‘summary measures’ such as mean and AM into time-dependent covariate survival analysis models, I was able to quantify the magnitude of increase in CAD risk associated with increments in systolic and diastolic BP, and to demonstrate and quantify the association between several lipids / lipoproteins and CAD risk in SLE. Using this methodology, I was also able to demonstrate that despite marked variability over time, ‘summary measures’ of hsCRP are independently predictive of CAD risk among patients with SLE, highlighting the pivotal role of inflammation in atherosclerosis. Furthermore, I was able to determine lipid and hsCRP ‘cut-points’ that will aid clinicians in identifying a subgroup of patients with SLE who are at significantly increased cardiac risk.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/35738 |
| Date | 24 July 2013 |
| Creators | Nikpour, Mandana |
| Contributors | Urowitz, Murray B., Gladman, Dafna D. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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