This thesis uses observational study design methods to explore the relationship between depression and various outcomes following acute myocardial infarction (AMI). There are three main studies. First, the relationship between depression and mortality following AMI was measured. The main finding was that the factor determining the increased mortality rate in depressed patients is reduced cardiac functional status. The main implication was that efforts to address increased mortality in depressed patients with cardiovascular illnesses should focus on processes that impact cardiac functional status. Second, the impact of depression on service consumption following AMI was examined. Depressive symptoms were associated with a 24% (Adjusted RR:1.24; 95% CI:1.19-1.30, P<0.001), 9% (Adjusted RR:1.09; 95% CI:1.02-1.16, P=0.007) and 43% (Adjusted RR: 1.43; 95% CI:1.34-1.52, P<0.001) increase in total, cardiac, and non-cardiac hospitalization days post-AMI respectively, after adjusting for baseline patient and hospital characteristics. Depressive-associated increases in cardiac health service consumption were significantly more pronounced among patients of lower than higher cardiac risk severity. The disproportionately higher cardiac health service consumption among lower-risk AMI depressive patients may suggest that health seeking behaviors are mediated by psychosocial factors more so than by objective measures of cardiovascular risk or necessity. Third, methodological issues related to missing data were explored. A systematic review of three psychiatric journals revealed that a small minority of studies (5.8%) addressed the impact of missing data in a meaningful way. An example using real data demonstrated the potential bias introduced by missing data and different ways to address this bias. The paper concludes with recommendations for both reporting and analyzing studies with substantial amounts of missing data.
Overall, the studies add to the literature exploring the relationship between depression and outcomes following acute myocardial infarction. Future studies measuring the relationship between depression and mortality will need to factor the mediating relationship between depression and cardiac functional status. The increased health service utilization associated with depression will need to be replicated in other illness models. Together, the studies add to the existing conceptual framework for measuring relationships between depression and outcomes in patients with cardiovascular illnesses.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/17471 |
| Date | 16 July 2009 |
| Creators | Kurdyak, Paul |
| Contributors | Goering, Paula N. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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