In this thesis, we addressed different issues related to drug exposure as it may bear on the estimates of risk in the context of hypertension treatment. A cohort of 19,501 subjects initiating therapy for uncomplicated hypertension was identified from Saskatchewan Health databases. In a first study aimed at documenting the equivalence of the angiotensin-converting-enzyme (ACE) inhibitors, we found that medical visits and hospitalizations following treatment initiation were lower among patients initially dispensed enalapril and lisinopril relative to captopril. Baseline characteristics could not be ruled out as possible explanations but variability in the outcomes suggest that ACE inhibitors may not be equivalent in all respects. Due to concerns about the appropriateness of using initial treatment as the exposure, patterns of use of antihypertensive were examined longitudinally in the second manuscript using the same cohort. ACE inhibitors, followed by calcium antagonists and beta-blockers, were the most commonly prescribed agents to initiate therapy for hypertension. Compliance with therapy was found to decrease over time with only 28% of patients still being compliant after seven years. In addition, 89% of patients underwent at least one modification to therapy, interrupted treatment being the most frequently encountered. Important differences were also found across agents with regard to compliance, type and timing of treatment modifications. The third manuscript reports on a case-control study assessing the association between antihypertensive drug use and the risk of myocardial infarction (MI). Overall, 812 cases of MI were identified using hospital discharge data and death certificates. Four controls were matched to each case on entry date and time at risk of an event. Compared with beta-blockers, current use of calcium antagonists was associated with an increased risk of MI (RR = 2.3; 95% Cl = 1.7--3.1). The risk ratio for ACE inhibitors was 1.3 (95% Cl = 1.0
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.36551 |
| Date | January 2000 |
| Creators | Bourgault, Chantal. |
| Contributors | Suissa, Samy (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Epidemiology and Biostatistics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001740469, proquestno: NQ64521, Theses scanned by UMI/ProQuest. |
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