Ethnicity and the first diagnosis of a wide range of cardiovascular diseases: Associations in a linked electronic health record cohort of 1 million patients

Abstract

Background: While the association of ethnic group with individual cardiovascular diseases has been studied, little is known about ethnic differences in the initial lifetime presentation of clinical cardiovascular disease in contemporary populations.

Methods and results: We studied 1,068,318 people, aged ≥30 years and free from diagnosed CVD at baseline (90.9% White, 3.6% South Asian and 2.9% Black), using English linked electronic health records covering primary care, hospital admissions, acute coronary syndrome registry and mortality registry (CALIBER platform). During 5.7 years median follow-up between 1997-2010, 95,224 people experienced an incident cardiovascular diagnosis. 69.9% (67.2%-72.4%) of initial presentation in South Asian <60 yrs were coronary heart disease presentations compared to 47.8% (47.3%-48.3%) in White and 40.1% (36.3%-43.9%) in Black patients. Compared to White patients, Black patients had significantly lower age-sex adjusted hazard ratios (HRs) for initial lifetime presentation of all the coronary disease diagnoses (stable angina HR 0.80 (95% CI 0.68-0.93); unstable angina- 0.75 (0.59-0.97); myocardial infarction 0.49 (0.40-0.62)) while South Asian patients had significantly higher HRs (stable angina- 1.67 (1.52-1.84); unstable angina 1.82 (1.56-2.13); myocardial infarction- 1.67 (1.49-1.87). We found no ethnic differences in initial presentation with heart failure (Black 0.97 (0.79-1.20); S Asian 1.04(0.87-1.26)). Compared to White patients, Black patients were more likely to present with ischaemic stroke (1.24 (0.97-1.58)) and intracerebral haemorrhage (1.44 (0.97-2.12)). Presentation with peripheral arterial disease was less likely for Black (0.63 (0.50-0.80)) and South Asian patients (0.70 (0.57-0.86)) compared with White patients.

Discussion: While we found the anticipated substantial predominance of coronary heart disease presentations in South Asian and predominance of stroke presentations in Black patients, we found no ethnic differences in presentation with heart failure. We consider the public health and research implications of our findings.

Trial registration: NCT02176174, www.clinicaltrials.gov.

Fig 1. Differences between ethnic groups in coronary, cardiac, cerebrovascular, abdominal and peripheral arterial disease diagnoses as a proportion of total incident cardiovascular disease and deaths from other causes, in three age bands (<60, 60–74, 75+).

Fig 2. Association between ethnic group and initial lifetime diagnosis of coronary, cardiac, cerebrovascular, abdominal and peripheral arterial diseases and deaths from other causes, adjusted* for age and sex.

Hazard ratios (HRs) of South Asian and Black patients compared to White patients; *adjustments included age, quadratic age, sex and stratification by primary care practice.

Fig 3. Association between ethnic group and initial lifetime diagnosis of coronary, cardiac, cerebrovascular, abdominal and peripheral arterial diseases and deaths from other causes, adjusted for age and sex*, CVD risk factors**, and medications***.

Hazard ratios (HRs) of South Asian and Black patients compared to White patients; *adjustments for age and sex included age, quadratic age, sex and stratification by primary care practice; adjustments for CVD risk factors further included deprivation, smoking, diabetes, systolic blood pressure, body mass index, total cholesterol, and HDL cholesterol; ***adjustment for medications further included statin use, anti-hypertensive drug use and oral contraceptives/HRT use in women only; SCD indicates sudden cardiac death, NOS, not otherwise specified.