Ethnic inequalities in cardiovascular disease: incidence, prognosis, and health care use Louise van Oeffelen Ethnic inequalities in cardiovascular disease: incidence, prognosis, and health care use PhD thesis, Utrecht University, The Netherlands ISBN: 978-90-393-6137-5 Author: Louise van Oeffelen Cover illustration: Olga Oliynik, www.nl123rf.com Cover design: Wendy Schoneveld, www.wenziD.nl Lay-out: Louise van Oeffelen Printed by: Wöhrmann Print Service B.V. Ethnic inequalities in cardiovascular disease: incidence, prognosis, and health care use Etnische verschillen in hart- en vaatziekten: incidentie, prognose en gebruik van gezondheidszorg (met een samenvatting in het Nederlands) Proefschrift ter verkrijging van de graad van doctor aan de Universiteit Utrecht op gezag van de rector magnificus, prof.dr. G.J. van der Zwaan, ingevolge het besluit van het college door promoties in het openbaar te verdedigen op dinsdag 3 juni 2014 des middags te 4.15 uur door Aloysia Adriana Maria van Oeffelen geboren op 31 juli 1984 te Terneuzen Promotoren: Prof.dr. M.L. Bots Prof.dr. K. Stronks Copromotoren: Dr. I. Vaartjes Dr. C.O. Agyemang The research described in this thesis was supported by a grant of the Dutch Heart Foundation (grant number: 2010B296). Financial support by the Dutch Heart Foundation for the publication of this thesis is gratefully acknowledged. Additional financial support by the Academic Medical Center Amsterdam, ChipSoft B.V., and Servier Nederland Farma B.V. for the publication of this thesis is also gratefully acknowledged. TABLE OF CONTENTS Chapter 1 General introduction 7 Chapter 2 Inequalities in incidence of acute myocardial infarction 17 2.1 Ethnic inequalities in acute myocardial infarction incidence in first 19 and second generation ethnic minority groups 2.2 Sex disparities in acute myocardial infarction incidence by ethnic 39 group 2.3 Time trends in acute myocardial infarction incidence by country of 55 birth 2.4 Incidence of first acute myocardial infarction over time by age, sex, 69 and country of birth 2.5 Socioeconomic inequalities in acute myocardial infarction incidence 87 by ethnic group Chapter 3 Inequalities in incidence of stroke 105 3.1 Ethnic inequalities in stroke incidence by stroke subtype and sex 107 3.2 Socioeconomic inequalities in stroke incidence by country of birth 123 Chapter 4 Inequalities in prognosis after cardiovascular disease 139 4.1 Ethnic inequalities in prognosis after acute myocardial infarction 141 and congestive heart failure 4.2 Socioeconomic inequalities in short-term mortality after acute 157 myocardial infarction Chapter 5 Inequalities in cardiovascular health care use 173 5.1 Ethnic inequalities in cardiovascular drug dispense and quitting 175 rates in primary care 5.2 Ethnic inequalities in revascularisation procedure rate after an ST- 193 elevation myocardial infarction 5.3 Ethnic inequalities in cardiovascular drug dispense and quitting 205 rates after a first acute myocardial infarction Chapter 6 General discussion 215 Chapter 7 Summary 237 Samenvatting 241 Dankwoord 246 Curriculum vitae 248 List of publications 249 CHAPTER 1 GENERAL INTRODUCTION General introduction BACKGROUND Although cardiovascular disease (CVD) has declined markedly over the past 30 years, it is still the main contributor to morbidity and mortality. In 2012, 20-22% of all European deaths were caused by coronary heart disease (CHD) and 10-15% by stroke. Other CVDs encompassed 12-15% of all deaths.1 CVD was also the largest single contributor to Disability Adjusted Life Years (DALYs) lost during 2012; 23% of all DALYs lost was due to CVD, mainly CHD (14%) and stroke (9%). CVD places therefore a huge burden on both patients and health care expenditure. Overall, CVD is estimated to cost the EU economy nearly 200 billion a year, of which 54% is due to direct health care costs, 24% to productivity loss, and 22% to informal care of people with CVD.1 Over the last decades it has become clearer that incidence and prognosis of cardiovascular disease differs between specific populations within a country.2 The growing number of multi-ethnic populations has led to the introduction of ethnic health research. Especially in the USA, where African minorities comprise a substantial part of the population for centuries, ethnic inequalities in cardiovascular disease incidence, prognosis, and health care use have been widely investigated. Higher acute myocardial infarction (AMI) incidence and mortality rates among African-American minorities than among their White American counterparts have been consistently reported. Some underlying factors described are a higher prevalence of traditional risk factors (hypertension, diabetes, hypercholesterolemia), a lower cardiovascular drug adherence, and a lower likelihood to receive effective and timely treatment in the acute care setting.3 In Europe, evidence on ethnic inequalities in CVD is less extensive. Difficulties in including ethnic minorities in large cohort studies may underlie the limited evidence so far.4 The majority of European research available originates from the UK where especially South-Asian minorities have been investigated. Compared with the UK majority population, South-Asian minorities are at higher risk for ischemic heart disease (IHD). Found explanations include a higher prevalence of the insulin resistance syndrome (characterised by hyperinsulinaemia, hyperglycaemia, diabetes, dyslipidaemia, elevated triglyceride, and reduced high density lipoprotein level), a more severe type of disease (higher prevalence of triple vessel disease, several lesions, and non-discrete lesions), and a lower likelihood of receiving (timely) revascularisation procedures.5 Also Scandinavian countries and the Netherlands have published some important findings regarding ethnic inequalities in CVD, although they mainly focused on differences in cardiovascular risk factors, and less often on incidence, prognosis, and explanatory factors such as health care use.6-22 Furthermore, some major ethnic minority groups in Europe, such as Moroccans, Turkish, and Chinese, remain significantly underexposed in ethnic health research. In this thesis we will therefore investigate ethnic inequalities in CVD incidence, prognosis, and health care use in a wide range of ethnic minority groups. 9 Chapter 1 ETHNIC MINORITY GROUPS IN EUROPE AND THE NETHERLANDS During the last few decades there has been a steady rise in migration flows towards Europe. Since the late 1980s the number of first generation ethnic minority groups (henceforth, migrants) living in European countries has doubled.23 In 2010, more than 47 million migrants lived in the 27 European Union (EU) member states, equivalent to 9.4% of the total population.24 Two of the largest migrant groups are from Turkish and Moroccan origin. The biggest new-flow of migrants originate from Romania. Other increasing migration flows since 2001 are from Polish and Chinese descent.23 The Netherlands is an increasingly ethnically diverse country. In 2012, the Dutch population consisted of 11.2% migrants, which is almost 2% higher than in the total EU27 population. Furthermore, 9.8% of the population was born in the Netherlands with at least one parent born abroad (second generation ethnic minorities). In total, 3.5 million Dutch citizens (21% of the total Dutch population) belonged to a first or second generation ethnic minority group in 2012.25 This percentage doubled since 1972, when only 9% of the Dutch population belonged to an ethnic minority group.26 Of the ethnic minorities, 9% is of Western origin and 12% of non-Western origin (mainly from Turkey, Morocco, Suriname, and the Netherlands Antilles).25 In the upcoming decennia, the ethnic minority population is expected to grow even further. Prognostic analyses show an increase from 21% in 2012 towards 31% in 2060. The growth will be most profound among non- Western ethnic minorities; from 12% in 2012 towards 18% in 2060. Currently, the age distribution among non-Western ethnic minority groups is relatively low; only 4% of them are ≥65 years of age. Prognostic studies estimate that in 2060 22% of all non-Western ethnic minority groups are ≥65 years of age, which will be only slightly less than within the ethnic Dutch population.27 Since cardiovascular disease is a condition of the elderly, reducing ethnic inequalities in cardiovascular disease will become even more important in the future. OBJECTIVES OF THIS THESIS The high and rising number of ethnic minority groups in European countries in addition to the limited evidence regarding ethnic inequalities in CVD incidence, prognosis and health care use in Europe has resulted in the following research objectives: 1. To assess inequalities in the incidence of non-fatal and fatal cardiovascular disease between ethnic minority groups and ethnic Dutch. 2. To assess inequalities in mortality and readmission rate after a first cardiovascular event between ethnic minority groups and ethnic Dutch. 3. To assess inequalities in cardiovascular health care use (drugs, procedures) between ethnic minority groups and ethnic Dutch. 10 General introduction DEFINITION OF ETHNIC BACKGROUND: THIS THESIS In this thesis ethnic background is defined by using the country of birth and parental country of birth, as described previously.28 A first generation ethnic minority is born abroad with at least one of the parents born abroad, whereas a second generation ethnic minority is born in the Netherlands with at least one of the parents born abroad. Those with both parents