Adherence to guideline-recommended secondary cardiovascular prevention therapy (statins and cardiac rehabilitation) has been demonstrated to reduce the risk of all-cause mortality (Statins RRR 0.25, 95% CI 0.19-0.30; Cardiac Rehabilitation RRR 0.26, 95% CI 0.14-0.36) and secondary events.1,2 Yet, ≥50% of patients discontinue statin use within 12-month after an initial prescription and completion of cardiac rehabilitation is ≤20% in Ontario.3,4 Low statin adherence and cardiac rehab completion limits patients from realizing the full benefits of therapy.
A meta-analysis of randomized controlled trials of adherence to statins for secondary prevention reported that nonadherence to statins was greater in non-white ethnicities compared to white ethnicities (OR 1.28, 95% CI 1.04-1.59) with geographical variation in outcomes.5 In respect to cardiac rehabilitation, the literature suggests that non-white ethnicities are less likely to complete cardiac rehabilitation compared to white participants.6,7 However, a gap remains in our knowledge of cardiac rehabilitation completion among immigrants due to lack of outcome reporting across clinical trials. The literature suggests that immigrants have improved health profiles relative to Canadian-born patients. Specifically, immigrants with ≤10 years of Canadian residency have greater medication adherence than immigrants with >10 of Canadian residency when compared to Canadian-born participants.6-9
This thesis was a planned sub-study of the Interventions Supporting Long-Term Adherence and Decreasing Cardiovascular Events (ISLAND) randomized control trial. The ISLAND study was a pragmatic, randomized controlled trial investigating the effect of educational reminders on adherence to guideline-recommended therapy post-myocardial infarction. Study participants were allocated in a 1:1:1 ratio to one of three groups: i) usual care, ii) educational reminders sent via post, or iii) combination post and interactive voice response educational reminders. Investigators were blinded to the allocation sequence, participant allocation, and outcome assessment. Medication adherence and completion of cardiac rehabilitation were assessed 12-months from baseline. This sub-study of ISLAND focused on participants who completed a 12-month outcome assessment with a recorded response to the following question, “Were you born a Canadian citizen?”.
Immigrants experienced greater odds of statin adherence at 7-days (OR 1.36, 95% CI 1.00-1.85) and 30 days (OR 1.36, 95% CI 0.96-1.94) at one-year post-myocardial infarction, after adjusting for age, diabetes, sex, and smoking status. We found no evidence that immigration status was associated with cardiac rehabilitation completion (OR 0.91, 95% CI 0.72-1.14) after adjusting for age, diabetes, sex, smoking status, average neighborhood income quintile, education, and marital status. The odds of statin adherence at 7-days (OR 1.33, 95% CI 0.89-2.18) and 30-days (OR 1.39, 95% CI 0.89-2.18) was greater in visual minorities than white patients, however the difference was not statistically significant. We found no evidence of an association between ethnicity and cardiac rehabilitation completion (OR 0.98, 95% CI 0.75-1.29). Our analysis could not fully evaluate the healthy immigrant effect due to an insufficient sample size of immigrants with <10 years of Canadian residency exposure (n=29).
In conclusion, we report a statistically significant 36% increase in the odds of 7-day and 30-day statin adherence in immigrants compared to Canadian-born patients. We also report that the odds of cardiac rehabilitation decreased by 9% in immigrants compared to Canadian-born patients at 12-months post-myocardial infarction but this was not statistically significant. Our findings offer support for the “healthy immigrant effect” continuing in immigrants with >10 years of Canadian residency exposure. We were unable to evaluate outcomes in immigrants with <10 years Canadian residency exposure due to a lack of sample size (n=29). / Thesis / Master of Science (MSc) / The primary purpose of this research project was to assess whether immigrants, individuals who reside in Canada but were born outside of the country, who have experienced a previous heart attack were adhere to heart health therapies better than Canadian-born patients. The heart health therapies of interest to our investigation are two guideline-recommended heart attack prevention therapies, statins and cardiac rehabilitation.
The study design of our research project was a cohort sub-study of the ISLAND randomized control trial which investigated adherence to heart health therapies in patients residing in Ontario, Canada.
Our major finding was that immigrants who lived in Canada for >10 years were more adherent to statin therapy for a previous heart attack compared to Canadian-born participants. Our findings support the hypothesis that immigrants tend to demonstrate behaviours associated with improved outcomes compared to their Canadian-born counterparts.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/24097 |
| Date | January 2018 |
| Creators | Shepherd, Shaun |
| Contributors | Schwalm, Jon-David, Ivers, Noah, Medical Sciences (Clinical Epidemiology and Health Care Research) |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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