Impact of South Asian Ethnicity on Long‐Term Outcomes After Coronary Artery Bypass Grafting Surgery: A Large Population‐Based Propensity Matched Study

Abstract

BackgroundEthnicity is an important predictor of coronary artery bypass graft surgery (CABG) outcomes. South Asians (SA), one of the largest ethnic groups with a high burden of cardiovascular disease, are hypothesized to have inferior outcomes after CABG compared to other ethnic groups. Given the paucity and controversy of literature in this area, the objective of this study was to examine the impact of SA versus the general population (GP) on long‐term outcomes following CABG.Method and ResultsUsing administrative databases and a surname algorithm, 83 850 patients (SA: 2653, GP: 81 197) who underwent isolated CABG in Ontario, Canada from 1996 to 2007 were identified; mean follow‐up was 9.1±3.9 years. SA were younger (SA: 61.7±9.4, GP: 64.1±10.0 years, standardized difference=0.25) with more cardiac risk factors, including diabetes (SA: 54.1%, GP: 34.9%, standardized difference =0.40). Propensity‐score matching resulted in 2473 matched pairs between SA and GP with all baseline covariates being balanced (standardized difference <0.1). Being a SA compared to the GP was protective against freedom from major adverse cardiac and cerebrovascular events, defined by all‐cause death, myocardial infarction, stroke, or coronary reintervention: Adjusted Cox‐proportional hazard ratio 0.91, 95% CI (0.83–0.99), adjusted‐P=0.04; this was also true for freedom from all‐cause mortality: hazard ratio 0.81, 95% CI (0.72–0.91), adjusted P=0.0004. The adjusted proportion of major adverse cardiac and cerebrovascular events was lower in the SA (SA: 34.7%, GP: 37.8%, McNemar P=0.03), driven largely by all‐cause mortality (SA: 20.4%, GA: 24.3%, McNemar P=0.001).ConclusionsContrary to existing notions, our study finds that being a SA is protective with respect to freedom from long‐term major adverse cardiac and cerebrovascular events and mortality after CABG. More studies are required to corroborate and explore causal factors of these findings.

Factors predicting one-year post-surgical mortality amongst older Asian patients undergoing moderate to major non-cardiac surgery – a retrospective cohort study

“…A large cohort study investigating 53,065 heart failure patients showed that one-year mortality was lower in Black, Hispanic and Asian patients compared to White patients [27] and a meta-analysis has shown that Indian and Malay ethnic groups in South East Asian countries are at higher risk to develop metabolic diseases like diabetes [28][29][30]. A propensity-matched study For every 1g/dL drop in haemoglobin done amongst coronary artery bypass graft patients showed that South Asian ethnicity had a survival benefit compared its predominantly White counterparts [31]. Our study has shown that even after removing the effect of ethnic variances in incidences of commonly studied comorbidities through multivariate logistic regression, ethnicity alone appears to be an independent predictor of one-year mortality.…”

Representation of racial minorities in cardiac surgery randomized clinical trials

“…3 In a meta-analysis by Benedetto et al, 24 In contrast, a study based on the Ontario database showed South Asian ethnicity to be associated with significantly lower all-cause death, myocardial infarction, stroke, and coronary reinterventions following CABG (adjusted hazard ratio, 0.91; 95% CI, 0.83-0.99; p = .04) when compared with general population. 26 analysis. They also found Hispanic and African American populations to be underrepresented (11.2% and 4%, respectively), while the Asian race was deemed as overrepresented (10.4%).…”

The Burden of Atherosclerotic Cardiovascular Disease in South Asians Residing in Canada: A Reflection From the South Asian Heart Alliance

“…88 In a large Canadian cohort of propensity-matched patients undergoing CABG, SAs had a higher freedom from major adverse cardiac or cerebrovascular events (defined as all-cause death, MI, stroke, or coronary reintervention (9% lower risk) driven by a 19% lower risk of all-cause mortality compared with the general population (mostly Caucasians) (mean follow-up 9.1 years). 89 Given the culmination of these data collected in a Canadian population, revascularization should be strongly considered in SA patients.…”