5.2.2. Data sources

The magnitude of the problem contrasts with the usual paucity, weak quality and comparability of data available on CVD beyond mortality, other than rigorous but limited studies carried out in certain geographical areas.

In this effort, mortality and morbidity data were taken from several sources of information and then processed and here reported: EUROSTAT (http://epp.eurostat.ec.europa.eu, 2007) for mortality data; WHO-HFA database (http://www.euro.who.int/hfadb, 2007), specific projects such as the World Health Organization MONItoring trends and determinants of Cardiovascular disease (WHO MONICA) (http://www.ktl.fi/monica/, 2007) and population-based registers for morbidity data; WHO-HFA database and WHO MONICA for risk factors distribution.

Following the recommendations of the EUROCISS Project - European Cardiovascular Indicators Surveillance Set - (http://www.cuore.iss.it/eurociss/en/rapporto03/rapporto2003.asp, 2007) IHD data available from different sources of information were age-standardized for 35-74 years using the EUROSTAT European population as standard. The age range 35-74 years is recommended because below 35 years events are rare and above 74 years age structure differs among European countries. Moreover, among individuals aged over 75 years CVD mortality becomes increasingly salient and is often associated to co-morbidities, which make data validation and prevention more difficult to realize. For stroke, data were age-standardized for 35-84 years: the recommended upper age limit is 84 years given that between 75 and 84 years the number of events doubles. Above 84 years of age it is difficult to determine actual stroke due to co-morbidity; including the expanded age range 85+ could therefore skew results and complicate data validation.

The most effective preventive measures usually target middle-aged and younger, therefore it is highly necessary to understand differences among countries in order to develop and implement appropriate preventive strategies.

Dynamics of CVD mortality in Western and Eastern Europe and regional variations [Muller-Nordhorn et al, 2007;  Muller-Nordhorn et al, 2004] were published by the World Health Organization of United Nations (WHO) (Pisa and Uemura, 1982; Uemura and Pisa, 1988; Thom, 1989; Thom et al, 1985), European Society of Cardiology (Sans et al, 1997) and Kesteloot (Kesteloot et al, 2006). Trends over time have been studied since 1950; the changes in cardiovascular and all-cause mortality were interpreted in the light of available evidence on changes in environmental risk factors (Kuulasmaa et al, 2000) and CVD medical care (Tunstall-Pedoe et al, 2000)

 

5.2.2.1. Ischemic heart disease

 

Mortality

EUROSTAT data were analyzed to obtain mortality rates (http://epp.eurostat.ec.europa.eu, 2007).

IHD mortality was defined as underlying ICD-10 codes I20-I25 (corresponding to ICD-9 codes 410-414). Age-specific total mortality rates for the average of the last 3 years available (2001-2003) in the European Union (EU) and the proportion of cause-specific mortality in the different age groups for circulatory system (IHD, stroke and other CVD), cancer and violence were calculated.

Age-standardized (35-74 years) mortality rates were calculated for the last ten years (1994-2003) to estimate trends. Thus, we present the data for the three year period 2001-2003 along with those already published (Pisa and Uemura, 1982; Uemura and Pisa 1988; Thom 1989; Thom et al, 1985; Sans et al, 1997; Kesteloot et al, 2006). For the 27 EU member states age-standardized (35-74 years) mortality rate are presented as average of the last 3 years available.

To make trends more visible, countries were divided into Baltic countries (Estonia, Latvia, Lithuania), Eastern European countries, distinguished in Central Eastern European countries (Czech Republic, Poland, Slovakia and former GDR-Eastern Germany) and Balkan Eastern European countries (Bulgaria, Hungary, Romania), Northern European countries (Denmark, Ireland, Finland, Sweden, United Kingdom), Central European countries (Belgium, Germany, Luxembourg, The Netherlands, Austria, Slovenia) and Southern European countries (Greece, Spain, France, Italy, Malta, Portugal). It may be interesting to note that Malta population has similar characteristics to those of Northern Europe and mortality rates are higher compared to those of the Mediterranean countries; therefore Malta might be considered as an outlier in the group of Southern European countries. The country with the lowest mortality rate and the one with the highest are both reported.

 

Morbidity

Hospital discharge diagnoses from WHO-HFA (http://www.euro.who.int/hfadb, 2007) were used to calculate hospital discharge rates for all CVD, IHD, acute myocardial infarction (AMI) and stroke; these data are scarce, therefore it was not possible to analyze temporal trends. Crude rates for all ages for the last year available (2003) are reported. Other data, such as on heart failure and arrhythmias, whose prevalence has greatly increased in recent years, are not available, mainly because the majority of countries send to the European organizations (EUROSTAT, HFA-WHO, OCSE) data for aggregated groups of causes of deaths and not for single codes. Information on these complication could be crucial for understanding morbidity and future trends in medical care.

The ICD codes for IHD (ICD-9 410-414; ICD-10 I20-I25) and for AMI (ICD-9 410; ICD-10 I21-I22) were used as main hospital discharge diagnosis.

Hospital discharges from revascularization procedures (Percutaneous Transluminal Coronary Angioplasty [PTCA] and Coronary Artery By-pass Graft [CABG]) are also reported. Data are published by the European Heart Network and come from the European Society of Cardiology, year 2000, which is the last year for which accurate data is available for the majority of countries (Allender et al, 2008).

From the mid 1980s to mid 1990s, the WHO MONICA Project assessed in 37 populations of 21 countries the relative contribution of IHD incidence, case-fatality, trends in classical risk factors and advancements in coronary care to the decline in CVD mortality. Data from the WHO MONICA Project (Tunstall-Pedoe et al, 1999) are reported for the age range 35-64 years as mean annual coronary events rates derived from 10-year surveillance (from mid 1980s to mid 90s). Annual change in coronary events and 28 day-case fatality are also reported; case fatality (including in- and out-of-hospital events) is affected by severity of the disease and impact of the treatments. These data, although collected several years ago and not necessarily representative of the countries in which they were located, were all collected and validated through the same standardized methodology, therefore they are comparable and still today are considered as a gold standard.

 

5.2.2.2. Stroke

 

Mortality

Following the recommendations of the EUROCISS Project - European Cardiovascular Indicators Surveillance Set - (http://www.cuore.iss.it/eurociss/en/rapporto03/rapporto2003.asp, 2007) EUROSTAT data were analyzed to obtain mortality rates (http://epp.eurostat.ec.europa.eu, 2007). Stroke mortality was defined as underlying ICD-10 codes I60-I69, G45 (ICD-9 codes 430-438). Age-standardized mortality rates for the age groups 35-74 and 35-84 years separately were calculated for the average of the last 3 years available in EU Member States.

The last ten years (1994-2003) were selected to estimate mortality trends. To make trends more visible, countries have been divided, as for IHD, into Baltic countries, Eastern European countries (distinguished in Central Eastern European countries and Balkan Eastern European countries), Northern European countries, Central European countries and Southern European countries. Malta is included among Northern Europe countries because mortality rates are higher compared to those of Mediterranean countries and the population has similar characteristics to those of populations of Northern Europe; such an approach is understood as open to criticism as it would also be reasonable to consider Malta as an outlier in the group of Southern European countries. The country with the lowest mortality and the one with the highest are both reported.

 

Morbidity

Hospital discharge diagnoses from WHO-HFA (http://www.euro.who.int/hfadb, 2007) and EUROSTAT (http://epp.eurostat.ec.europa.eu, 2007) were used for stroke; these data are scarce, therefore temporal trends were not analyzed. Crude rates for all ages for the last year available (2003) are reported.

The ICD morbidity codes for stroke (ICD-9 430-438; ICD-10 I60-I69,G45) were used as main hospital discharge diagnosis.

Data from the WHO MONICA Project (http://www.ktl.fi/monica/, 2007) are reported for the age range 35-64 years as mean stroke attack rates derived from the last 3 years of surveillance. Annual change in stroke events and 28-day case fatality are also reported; case fatality (including in- and out-of-hospital events) is affected by severity of the disease and impacts of the treatments. As already explained, MONICA data, although collected several years ago and not necessarily representative of the countries in which they were located, were all collected and validated through the same standardized methodology, therefore they are comparable and still today are considered a gold standard. The definition of stroke used in the WHO-MONICA Project (http://www.ktl.fi/monica/, 2007) was based on clinical findings (symptoms, signs and clinical examination); therefore, it was not dependent on access to more sophisticated diagnostic techniques (Computed Tomography Scan [CT-Scan] and Magnetic Resonance Imaging [MRI]).

 

5.2.2.3 Risk factors

CVD clinically manifests itself in middle life and older age, after many years of exposure to unhealthy lifestyle (smoking habit, unhealthy diet, physical inactivity) and risk factors (elevated total and low density lipoprotein cholesterol, high blood pressure, diabetes, obesity). CVD is a multifactorial disease, which means that several predisposing factors simultaneously affect its development, although each of them plays a different role: to give an example, hypertension, smoking habit and excessive alcohol consumption have a major role in predicting stroke; elevated total and LDL cholesterol, low HDL cholesterol,  hypertension, diabetes and smoking are crucial to explain differences in IHD. Among all CVD risk factors, age remains the most important risk factor for CVD.

Last available data on risk factors were taken from WHO HFA database (http://www.euro.who.int/hfadb, 2007). The risk factors identified as the most important at population level were selected: hypertension, hypercholesterol, obesity, diabetes and smoking habit. Due to differences among countries in the methodology adopted for data collection (self reported or measured), the diagnostic criteria adopted in risk definition (hypertension and hypercholesterol) and the age ranges considered, it was not possible to pool data and then give a more complete overview.

Therefore, some data from the WHO MONICA Project, collected at the beginning of 1990s using standardized procedures and methods, are reported as well (Kuulasmaa et al, 2000).