South Asians and coronary disease: is there discordance between effects on incidence and prognosis?

Abstract

ObjectiveTo determine whether the effect of South Asian ethnicity differs between studies of incidence and prognosis of coronary disease.DesignSystematic literature review and meta-analysis, and cohort analysis from a national acute coronary syndrome (ACS) registry linked to mortality (National Institute of Cardiovascular Outcomes Research/Myocardial Infarction National Audit Project).SettingInternational for the review, and England and Wales for the cohort analysis.PatientsThe numbers of South Asians included in the meta-analysis were 111 555 (incidence) and 14 531 (prognosis) of whom 8251 were from the ACS cohort.Main outcome measuresIncidence studies: non-fatal myocardial infarction or fatal coronary heart disease; prognostic studies: mortality; HRs for 1-year all-cause death in ACS cohort.ResultsSouth Asians had higher incidence of coronary disease compared with white subjects (HR 1.35 95% CI 1.30 to 1.40) based on meta-analysis of nine studies. Among 10 studies on prognosis, South Asians had better prognosis compared with white subjects (HR 0.78 95% CI 0.74 to 0.82). In the ACS cohort, the impact of diabetes (42.4% of South Asians, 16.9% of white subjects) on 1-year mortality was stronger in South Asians than white subjects (age-adjusted HR 1.83 95% CI 1.59 to 2.11 vs 1.53 95% CI 1.49 to 1.57). However, prognosis was better in South Asians even among diabetics, older people and those living in areas of the highest social deprivation.ConclusionsSouth Asian ethnicity is associated with higher incidence of coronary disease, but lower mortality once coronary disease is manifest. The dissociation between effects on incidence and prognosis suggests that public health initiatives to reduce inequalities in mortality between South Asian and white populations should focus on primary prevention.This is a CALIBER study with ClinicalTrials.gov Identifier: NCT01163513.

Cardiovascular Disease in South Asian Migrants

“…35 Zaman and colleagues found that SA in the UK had a higher incidence of CAD but M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 8 paradoxically lower mortality once a diagnosis was made (HR 0.78, CI 0.74-0.82) and SA with DM had a better prognosis compared to Europids with DM. 20 Given the varying results, factors influencing prognosis following cardiac events in SA may be dependent on the specific population and country studied, perhaps changing over time and across nations. Specifically, SA ethnicity may not independently worsen CAD prognosis once the greater burden of DM is accounted for.…”

Demographic and angiographic profile in premature cases of acute coronary syndrome: analysis of 820 young patients from South India

“…Despite being identified as a major burden on health-care systems, there have been no large prospective cohort studies to define the incidence of coronary artery disease (CAD) among Indians. Therefore, the magnitude of the problem can only be estimated from cross-sectional point prevalence studies (3). Reports have shown that risk of CAD among Asian Indians is 3-4 times higher than white Americans, 6 times higher than Chinese, and 20 times higher than Japanese counterparts (4).…”

Using nationwide ‘big data’ from linked electronic health records to help improve outcomes in cardiovascular diseases: 33 studies using methods from epidemiology, informatics, economics and social science in the ClinicAl disease research using LInked Bespoke studies and Electronic health Records (CALIBER) programme

“…subarachnoid haemorrhage), the strength and shape of association of age with many CVDs varies substantially, and those of South Asian ethnicity experience substantially increased hazard of stable and unstable coronary presentations compared with white people 34,35 Estimates of national and global burden of CVDs need to take account of the modern epidemic in which heart failure, PAD and other chronic diseases are becoming more common than AMI and stroke. Male sex, older age, South Asian ethnicity and low social deprivation, although associated with many CVDs, are not associated with all, and this heterogeneity has implications for research into risk prediction, aetiology and prognosis Study 5: there was a discordance between incidence of SCAD, which was markedly higher among those of South Asian ethnicity than for those of white ethnicity, and prognosis which was significantly better in South Asians 36 Large-scale EHR cohort studies with detailed measures over time of clinical risk, and patient care identified through linkage of primary care, ACS registry, hospitalisation and cause-specific death data are warranted to better understand how South Asian ethnicity influences the onset and progression of coronary and other CVDs. Such studies will allow longitudinal patterns of risk and missed opportunities to lower risk before admission and after discharge to be evaluated In clinical trial design, selection of primary end points is crucial and should reflect the mechanism of action of the intervention and, where appropriate, the public health burden of CVDs in the 21st century.…”