Analysing causes of death provides a betterunderstanding of long-term mortality trends. InFrance, the death certificates completed by physiciansgenerally mention several causes of death (2.4 onaverage in 2011). As a general rule, just one of them,the so-called underlying cause, is taken into account.As a result, the contribution of certain diseases-endocrine diseases for example-to mortality isseverely underestimated. In a context of rising lifeexpectancy where people increasingly die not from asingle cause of death but from several, it is importantto also take these contributing causes into account

Barbieri, M

Demuru, E

Denissov, G

Désesquelles, A

Egidi, V

Frova, L

Gamboni, A

Goldberger, N

Grundy, E

Marshall, C

Meslé, F

Pappagallo, M

Pechholdova, M

Sakkeus, L

University of Essex Research Repository

Aline Désesquelles,* Andrea Gamboni,** Elena Demuru** and the MultiCause networkWhen a person dies, the certifying physician records the cause of death on the death certificate. In many cases, several causes are mentioned, as well as the train of events that led to death. Aline Désesquelles and her colleagues explain why this type of information is useful for studying trends in causes of death in a country, and why international comparisons are difficult, notably because of cross-national differences in the ways medical certificates are completed.   We only die once…  but from how many causes?Life expectancy in France has increased considerably over recent decades, thanks mainly to a decline in mortality from circulatory diseases and cancers, the two leading causes of  death. We know this because statistics on all causes of  death are compiled by the CépiDc (Centre d’épidémiologie sur les causes médicales de décès), the French body responsible for producing cause-of-death data from the certificates filled in by physicians when they certify a death (Box 1). Analysing causes of  death sheds light on mortality * French Institute for Demographic Studies.** University of Rome. In alphabetical order: Magali Barbieri (INED/University of Berkeley), Gleb Denissov (Estonian Causes of Death Registry), Viviana Egidi (University of Rome), Luisa Frova (ISTAT), Nehama Goldberger (Israelian Ministry of Health), Emily Grundy (London School of Economics), Christopher Marshall (University College London), France Meslé (INED), Marilena Pappagallo (ISTAT), Marketa Pechholdova (University of Economics, Prague), Luule Sakkeus (Estonian Institute for Population Studies).Box 1. Determining the cause of deathThe medical certificate of death used in France complies with the recommendations of the World Health Organization (WHO). It is in two parts. In part I, the physician describes the train of events that led directly to the death. This first part has four lines, although physicians some-times mention several causes on a single line. In part II, the physician is asked to indicate any other “morbidity, physiological factor or condition contributing to death but not involved in the process described in part I”. In 2011, three-quarters of the causes mentioned on death certificates were given in part I, but for 30% of deaths, at least one other cause was listed in part II. The information recorded by the physician is coded by the CépiDc which, again in compliance with WHO recommendations, determines the underlying cause, i.e. the disease or injury that initiated the train of events leading directly to death. In the majority of cases, and if the certifi-cate is filled in correctly, this is the last cause listed in part I. All the other causes mentioned on the certificate, in both part I and part II, are called “contributing causes”.  www.ined.frPopulation      Societies&Number 534 • June 2016 • Population & Societies •Number 534June 2016Versionfrançaise Contributing causes are important for medicine and public health policiesCauses other than the underlying cause are called “contributing causes”. They contribute to death in three ways.[2] Most often, they are consequences or complications of  the underlying cause or its treatment and, if  so, they are mentioned in part I of  the death certificate. For example, a haemorrhage due to a gastric ulcer, or septicaemia in a cancer patient whose immune system has been weakened by chemotherapy would come under this category. Contributing causes may also be risk factors for the underlying cause, such as chronic viral hepatitis for liver cancer, for example. Last, they may also interact with the underlying cause by increasing its severity, further weakening the patient or making treatment more complex or less effective. Chronic diseases such as diabetes or hypertension are often involved in this way in the train of  events leading to death. Whatever the means by which they contribute to death, there is no doubt that progress in the prevention and treatment of  contributing causes will have a positive impact on life expectancy. For this reason, they deserve to be considered more fully in statistical and epidemiological studies. These causes are underestimated in statistics on underlying causes of deathFor seven countries of  the MultiCause network (Box 3), Figure 2 shows the ratio between the standardized mortality rates (I) calculated on the basis of  all causes mentioned on the death certificates (also called “multiple causes”) and the rates based solely on the underlying cause. The calculations concern deaths of  persons aged 65 and above. Seven chapters of  the International Classification of  Diseases (ICD) (Box 2) were selected to illustrate the range of  situations encountered. The ratio varies substantially by cause of  death and country. The trends, which may change rapidly or evolve slowly over time.  It provides pointers for focusing public health policies on particular targets in order to further reduce mortality or to warn about potential health threats.  All causes mentioned on death certificates are recorded and coded by CépiDc, but analyses generally look at just one, the so-called “underlying” cause of  death (Box 1). Yet death certificates often mention several causes. Is it useful to take these other causes into account? From no defined cause…  to more than 15 causes!In France, if  ill-defined causes are excluded (Box 2), 2.4 causes of  death, on average, are mentioned on the death certificates of  persons who died in 2011.  For one in ten deaths, the cause is unknown or ill-defined. The proportion is higher for persons who died before age 50, when deaths are more often due to “external causes” (accident, suicide, homicide, etc.). In such cases, if  the death is investigated by a coroner, CépiDC does not always receive the death certificate. Almost one-quarter of  death certificates in 2011 mentioned just one cause, and a similar proportion mentioned at least four. The record was 20 causes on a single certificate. The number of  causes mentioned increases with age, up to age 80 at least (Figure 1). At ages 65-79, 24% of  certificates listed at least four causes, compared with 14% at ages below 35. This rise reflects the increasingly complex disease profiles of  the oldest adults, who are often affected by several different illnesses simultaneously. Beyond age 80, the mean number of  listed causes drops slightly (2.4 versus 2.6 at ages 65-79) and a much higher proportion of  deaths have no recorded cause. For older adults who “die of  old age”, physicians perhaps find it less useful to give a precise description of  the train of  events that led to death. (1)  To ensure comparability, the rates of the different countries are calculated for an identical population age structure. * All causes of death, on parts I and II of the certificate, are included. “Ill-defined” causes are not counted. Source: CépiDc cause-of-death statistics.Figure 1. Number of causes of death mentioned* on death certificates by age group, France, 2011Box 2. Defined and ill-defined causesThe International Classification of Diseases (ICD) of the World Health Organization [1] lists and classifies all diseases, injuries and other health problems. It is used, among other things, to code the causes of death. The latest version of the ICD (10th revision) comprises 21 chapters concerning “special groups” of diseases (infectious diseases, neoplasms, etc.) or the various “body systems” (circulatory system, respiratory system, etc.). In our study, ill-defined causes are those listed in the chapter “Symptoms, signs and abnormal clinical and laboratory fin-dings”, as well as certain ill-defined morbid states, such as cardiac arrest, that are classified elsewhere.051015202530%01234 +Below 35 All deaths80 +65-79s50-6435-492 www.ined.frWe only die once… but from how many causes?Number 534 • June 2016 • Population & Societies •higher the ratio, the greater the extent to which the role of  the disease or condition in mortality is underestimated if  only the underlying cause is considered.Diseases of  the circulatory system and neoplasms (cancers), the two leading underlying causes of  death in these seven countries, are largely unaffected when contributing causes are taken into account: when they are recorded on the death certificate, in more than half  of  cases – and in practically all cases for neoplasms – they are the underlying cause of  death. With the exception of  England-Wales, this is also the case for external causes of  death. By contrast, for diseases of  the blood, whose position in the hierarchy of  underlying causes of  death is very low, the ratio between  the “multiple causes” and “underlying cause” mortality rates is often high.  While often recorded on death certificates, blood diseases are rarely given as the underlying cause of  death.  Between these extremes, we find a set of  diseases for which the ratio is almost always above 2, but with substantial variability across countries. This is the case for respiratory diseases, for example, which generally rank third or fourth in the list of  underlying causes of  death, and for which the ratio ranges from 2.2 in the United States to 6.6 in the Czech Republic. This variation probably reflects differences between countries in the way in which pneumonia is certified and coded.[3]The example of endocrine, nutritional and metabolic diseasesThe contribution of  endocrine, nutritional and metabolic diseases to mortality is also severely under-estimated when only their role as the underlying cause is taken into account.  Diabetes and obesity, which are included in this group of  diseases, often complicate the treatment of  patients who are also affected by other diseases. While the standardized “underlying cause” mortality rate is similar in France, Italy, the United States and the Czech Republic, it is half  as high in England-Wale and Estonia, and twice as high in Israel (Figure 3). When contributing causes are taken into account, the country rankings are very different. The increase is so spectacular for the Czech Republic that it almost catches up with Israel at the top of  the list. Italy, the United States and France, in that order, stand out more clearly. Last, despite a high ratio between the “multiple causes” and “underlying cause” mortality rates, England-Wales and Estonia still have much lower levels than the other countries. Beyond probable differences in the prevalence of  these diseases, the ways in which they contribute to death seem to vary across countries, more often as contributing causes in Estonia and the Czech Republic, and as underlying cause in Israel. Differences between countries in the way in which multiple causes are certified and coded, and in the choice of  underlying cause may also partly explain these divergences. [4] In Israel, for example, on death certificates where both diabetes and a cardiovascular disease are listed, diabetes is given as the underlying cause more frequently than elsewhere. * The groups of causes of death are classified by order of impor-tance in terms of the “underlying cause” mortality rate. ** Except Czech Republic: 2011 data.Interpretation: for diseases of the circulatory system, the ratio between the mortality rate based on all causes listed on the death certificate and the mortality rate based on the underlying cause only is around 1.5 in France, Italy and the United States, 2.1 in Israel, 1.2 in Estonia and 1.3 in England-Wales.Source: MultiCause Network.Figure 2. Ratio between “multiple causes” and “underlying cause” mortality rates for 7 groups of causes* and 7 countries, deaths at age 65+, 2009** * Standardized mortality rate, for an identical age distribution.** Except Czech Republic: 2011 data.Interpretation: if we consider only deaths where an endocrine, nutri-tional and metabolic disease is certified as the underlying cause of death, we obtain the rate in red (underlying cause), but if we also consider deaths where this type of disease is mentioned, but not as an underlying cause, we obtain a higher rate (underlying cause plus contributing cause). Source: MultiCause Network.Figure 3. Mortality rate* from endocrine, nutritional and metabolic diseases, deaths at age 65+, 2009** Contributing causeUnderlying causeIsraelCzechRepublicItalyUnitedStatesFranceEngland-WalesEstoniaRate per 100,00002004006008001,0001,2001 2 3 4 5 > = 6 Diseases ofthe circulatory systemEndocrine, nutritional andmetabolic diseasesNeoplasms (cancers)Diseases of therespiratory systemDiseases of thedigestive systemExternal causes of deathDiseases of the blood and the blood-forming organs, and certain disordersinvolving the immune mechanismEngland-WalesUnited StatesEstonia France Israel Italy Czech Republic 3www.ined.frWe only die once… but from how many causes?Number 534 • June 2016 • Population & Societies •Analysing causes of death provides a better understanding of long-term mortality trends. In France, the death certificates completed by physicians generally mention several causes of death (2.4 on average in 2011). As a general rule, just one of them, the so-called underlying cause, is taken into account. As a result, the contribution of certain diseases –  endocrine diseases for example  – to mortality is severely underestimated. In a context of rising life expectancy where people increasingly die not from a single cause of death but from several, it is important to also take these contributing causes into account.Abstractto standardize and harmonize the recording of  causes of  death on the death certificate and during the coding stage. Looking at the “multiple” causes of  death is useful for determining the one “underlying” cause. This multiple-causes approach is especially important in a context of  population ageing, where deaths from a single cause will become increasingly infrequent. References[1] WHO, 1992, International Statistical Classification of Diseases and Related Health Problems: Tenth Revision.[2] Désesquelles A., Salvatore M.A., Pappagallo M., Frova L., Pace M., Meslé F., Egidi V., 2012, “Analysing multiple causes of death: Which methods for which data? An appli-cation to the cancer-related mortality of France and Italy”, European Journal of Population, 28(4), pp. 467-498.[3] Désesquelles A., Demuru E., Pappagallo M., Frova L., Meslé F., Egidi V., 2015, “After the epidemiologic transi-tion: A reassessment of mortality from infectious diseases among over-65s in France and Italy”, International Journal of Public Health, 60, pp. 961-967.[4] Anderson R.N., 2011, “Coding and classifying causes of death: Trends and international differences”, in Rogers R.G., Grimmins E.M. (eds.) International Handbook of Adult Mortality, New York, NY, Springer, pp. 467-489.[5] Goldberger N., Applbaum Y., Meron J., Haklai Z., 2015, “High Israeli mortality rates from diabetes and renal failure – Can international comparison of multiple causes of death reflect differences in choice of underlying cause?”, Israel Journal of Health Policy Research, 4(31).Towards greater harmonization in the recording of causesWhat did this person die of ? While the habit of  giving a single cause of  death is deeply rooted, the reality is often more complex. The WHO instructions for completing the death certificate are supposed to help the certifying physicians to manage this complexity. Yet countries often still use certificates that deviate slightly from the WHO recommendations. For example, the amount of  space and number of  lines provided in each part to describe the train of  events leading to death may differ. While people in the Czech Republic, in Israel and Italy probably do not die of  more causes than in France, the mean number of  causes listed on death certificates in these countries is above 3. Moreover, the WHO certificate gives a certain latitude regarding the degree of  precision of  the description which, of  course, also depends on the amount of  information available to the physician. So the international research community must pursue its efforts Box 3. The MultiCause networkMultiCause is an international research network set up to ana-lyse all causes recorded on death certificates. As well as re-evaluating mortality levels, it is also interested in describing associations between causes. Founded in 2012, MultiCause now brings together researchers from around 20 countries. The indicators used for this study were calculated by network mem-bers on the basis of national death statistics produced by the following bodies:- England - Wales: Office for National Statistics (ONS) Longitu-dinal Study (0300770).  Data from ONS are Crown Copyright. The use of the ONS statistical data in this work does not imply the endorsement of the ONS in relation to the interpretation or analysis of the statistical data - United States: National Center for Health Statistics (NCHS)- France : CépiDc, National Institute for Health and Medical Research (INSERM)- Israel : Ministry of Health- Italy : Italian National Institute of Statistics (ISTAT)- Czech Republic: Institute for Health Information and Statistics (IHIS)All these countries have adopted a medical certificate of death that complies with WHO recommendations and use the 10th revision of the ICD to code causes of death.Ined: 133, boulevard Davout, 75980 Paris, Cedex 20 Director of Publications: Magda TomasiniEditor-in-chief: Gilles Pison Editorial assistant: Marie-Paule ReydetTranslator: Catriona Dutreuilh, Roger DepledgeLayout: Isabelle MilanPrinter: Mérico Delta Print, Bozouls, FranceD.L. 2nd quarter 2016 • ISSN 0184 77 83No 534 • June • Population & Societies Monthly bulletin of the French Institute for Demographic StudiesEvery issue of Population & Societies is immediately accessible on the INED website: www.ined.fr/en/publications/For an e-mail publication alert (11 annual issues): www.ined.fr/en/publications/population-and-societies/For a postal subscription to Population & Societies (in French): www.ined.fr/en/publications/abonnements/abonnements-population-et-societes/We only die once… but from how many causes?

We only die once... but from how many causes?

We only die once... but from how many causes?

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