Elsevier

Canadian Journal of Cardiology

Volume 28, Issue 2, March–April 2012, Pages 178-183
Canadian Journal of Cardiology

Clinical research - health care outcome
Outcomes in Young South Asian Canadians After Acute Myocardial Infarction

https://doi.org/10.1016/j.cjca.2011.10.014Get rights and content

Abstract

Background

South Asians have a high prevalence of ischemic heart disease and experience high incident acute myocardial infarction (AMI) rates at younger ages than their white counterparts. The aim of this study was to compare outcomes after AMI in a Canadian population of South Asian and white patients, aged 20 to 55 years.

Methods

Using hospital discharge abstract administrative data, we included patients with incident AMI, residing in British Columbia and the Calgary Health Region, between April 1, 1995 and March 31, 2002. The cohort was followed for up to 8 years (mean 4.2 years) to determine outcomes of mortality, recurrent AMI, and congestive heart failure (CHF) requiring hospitalization. South Asian ethnicity was determined using validated surname analysis. Baseline demographic characteristics and comorbidities were adjusted using Cox proportional hazard models.

Results

Of 7135 young patients with AMI, 487 were of South Asian ancestry. Compared with white patients, South Asian patients were more likely to have diabetes (25% vs 12%) and hypertension (24% vs 20%). After adjustment for sociodemographic and comorbidity variables, there were no significant differences in rates of 30-day mortality (risk adjusted hazard ratio [aHR] 0.90; 95% confidence interval [CI], 0.38-2.10), long-term mortality (aHR 0.81; 95% CI, 0.53-1.26), recurrent AMI (aHR 1.07; 95% CI, 0.89-1.29), or CHF (aHR 0.90; 95% CI, 0.51-1.59) between the 2 groups.

Conclusions

Despite the recognition of increased cardiovascular mortality among young South Asian patients, our Canadian sample demonstrated similar rates of fatal and nonfatal outcomes among young South Asian and white patients with AMI.

Résumé

Introduction

Les Sud-Asiatiques ont une prévalence élevée de cardiopathie ischémique et connaissent des taux d'incidence élevés d'infarctus aigu du myocarde (IAM) à un plus jeune âge que leurs homologues blancs. Le but de cette étude était de comparer les conséquences après l'IAM chez une population canadienne de patients sud-asiatiques et blancs âgés de 20 à 55 ans.

Méthodes

En utilisant les données administratives des sommaires sur les congés d'hôpital, nous avons inclus les patients ayant une incidence d'IAM, résidant en Colombie-Britannique et de la Calgary Health Region, entre le 1er avril 1995 et le 31 mars 2002. La cohorte a été suivie durant une période allant jusqu'à 8 ans (moyenne de 4,2 ans) pour déterminer la mortalité, la récidive d'IAM et l'insuffisance cardiaque congestive (ICC) nécessitant l'hospitalisation. L'ethnicité sud-asiatique a été déterminée en utilisant l'analyse patronymique. Les caractéristiques démographiques de base et les comorbidités ont été ajustées selon le modèle de risques proportionnels de Cox.

Résultats

Des 7 135 jeunes patients ayant un IAM, 487 étaient d'ascendance sud-asiatique. Comparativement aux patients blancs, les patients sud-asiatiques étaient plus susceptibles de souffrir de diabète (25 % vs 12 %) et d'hypertension (24 % vs 20 %). Après l'ajustement des variables sociodémographiques et de comorbidité, il n'y a eu aucune différence significative dans les taux de mortalité à 30 jours (rapport de risque ajusté [RRa], 0,90; intervalle de confiance [IC] de 95 %, 0,38-2,10), de mortalité à long terme (RRa, 0,81; IC de 95 %, 0,53-1,26), de récidive d'IAM (RRa, 1,07; IC de 95 %, 0,89-1,29) ou d'ICC (RRa, 0,90; IC de 95 %, 0,51-1,59) entre les 2 groupes.

Conclusions

Même si l'on reconnaît l'augmentation de mortalité cardiovasculaire chez les jeunes patients sud-asiatiques, notre échantillon canadien a démontré des taux similaires de conséquences fatales ou non fatales chez les patients sud-asiatiques et blancs ayant un IAM.

Section snippets

Study population

This retrospective cohort study included patients with AMI, 20-55 years of age residing in British Columbia and the Calgary Health Region, Canada. Data were obtained from routinely collected hospital administrative discharge records from April 1, 1995 to March 31, 2002. The hospital discharge abstract database (DAD) contains demographic and clinical data with up to 25 diagnoses for each hospital discharge. Patients were identified as having an AMI based on validated International Classification

Results

Of the 40,669 patients identified with AMI, there were 7135 patients younger than the age of 55. Of these, 487 patients (6.8%) were categorized as South Asian. Patients were followed for up to 8 years (mean 4.2 years). The young cohort had a significantly lower percentage of women and overall lower prevalence of comorbidities compared with the cohort older than the age of 55.

Baseline characteristics are presented in Table 1. Both ethnic groups were similar in most aspects. However, South Asian

Discussion

In our study, we found no significant differences in fatal and nonfatal events after AMI. While there is recognition of the increased cardiovascular mortality among young South Asian patients, there has been minimal work done in examining outcomes of young survivors of AMI. Our work provides a closer examination of this young population at high risk for future cardiovascular complications. With a large population-based study and several years of follow-up, we were able to follow young South

Conclusions

Premature atherosclerosis remains a major health concern among young South Asians. When adjusting for sociodemographic factors and comorbidities, we found no difference in fatal and nonfatal outcomes after AMI among South Asian and white patients younger than the age of 55.

Although it is recognized that young South Asian patients have a high prevalence of AMI, they are not experiencing worse outcomes relative to young white patients, according to results in our study. The complex factors and

Funding Sources

This study was funded by the Canadian Institutes of Health Research (CIHR). CIHR had no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication.

Disclosures

The authors have no conflicts of interest to disclose.

Acknowledgements

We thank the British Columbia Cardiac Registry, the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH), and the British Columbia and Alberta Ministries of Health for providing access to data.

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