Cardiovascular disease recurrence and long-term mortality in a tri-ethnic British cohort: a retrospective study

Abstract

Abstract Background People of South Asian and of African Caribbean descent have elevated risks of some cardiovascular diseases compared to Europeans. How ethnicity relates to recurrent risk, and explanations for between ethnic group differences in recurrence are unclear. We characterized long-term risk of major adverse cardiovascular event (MACE) and mortality following a non-fatal cardiovascular event in a tri-ethnic British cohort. Methods We linked hospital and mortality records of a population-based cohort of South Asian, African Caribbean and European men and women aged 40–69 years with no prior history of cardiovascular disease. We identified index and recurrent cardiovascular events (stroke, transient ischaemic attack, myocardial infarction, or ischaemic heart disease), and mortality from 1988 to 2017. Using multivariable proportional hazards models, we separately calculated the adjusted hazard ratios (HR) of MACE and death following index event. We adjusted for demographics, vascular and lifestyle risk factors. We used interaction terms to evaluate if diabetes or decade of index event modified the association between ethnicity and outcomes. Results We included 801 participants with first non-fatal cardiovascular events, 647 coronary and 127 cerebrovascular, of whom 335 (41.8%) were European, 396 (49.5%) South Asian, and 70 (8.7%) African Caribbean. During a mean follow-up of 5.3 years, 537 patients developed MACE and 338 died. Crude incidence rate of MACE was higher in South Asians (135.9 per 1000-person-years) compared to Europeans (117.1) and African Caribbeans (123.6). Higher risk of MACE in South Asian compared to Europeans was eliminated in the adjusted models (HR 0.97, 95% confidence interval 0.77–1.21), whereas their mortality advantage was eliminated when the younger age at index event was accounted for (HR 0.95, 0.72–1.26). African Caribbeans had similar outcomes to Europeans (HR MACE 1.04, 0.74–1.47; and HR death 1.07, 0.70–1.64). There was no modification by diabetes for outcomes, whereas survival following index event improved more in South Asian, than African Caribbean, compared to European over three decades (Pinteraction = 0.04). Conclusions Baseline vascular risk factors explained the observed ethnic variation in cardiovascular disease recurrence and long-term mortality, with a relative improvement in survival of minority ethnic groups over time. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): UK Medical Research Council, Wellcome Trust