Review of death certificate diagnosis of coronary heart disease and heart failure in Japan

Vital statistics for coronary heart disease (CHD) were dramatically influenced by the tenth revision of the International Classification of Diseases (ICD-10) in 1995. To better understand the accuracy of death certificate diagnosis of CHD and heart failure, validation studies in Japan were reviewed. Positive predictive values and sensitivity, calculated as validation measures, varied widely between studies, differing with regard to autopsy rates, amount of information on medical records, and period investigated. However, heart failure, which has been frequently assigned on death certificates in Japan, was validated in some studies. Half of these were evaluated to be sudden deaths, including coronary deaths. Because autopsy-based studies on sudden deaths indicated that 30-50% of these were accounted for by CHD deaths, deaths assigned to heart failure should be taken into consideration in order to determine the actual number of CHD deaths in Japan. Focusing on changes in vital statistics after the 1995 ICD revision, the Oita Cardiac Death Surveys (OCDS) allowed interpretation of its effects on CHD and heart failure. Much of the increase in CHD deaths on vital statistics reflects more false positive cases, particularly for out-of-hospital deaths. Considering the Japanese features of vital statistics for CHD, further epidemiological validation studies are needed in order to confirm the accuracy of CHD death certificate diagnoses and to monitor actual CHD trends in Japan.     

Validation of death certificate diagnosis for coronary heart disease: the Atherosclerosis Risk in Communities (ARIC) Study

The validity of the death certificate in identifying coronary heart disease deaths was evaluated using data from the community surveillance component of the Atherosclerosis Risk in Communities Study (ARIC). Deaths in the four ARIC communities of Forsyth Co., NC; Jackson, MS; Minneapolis, MN; and Washington Co., MD were selected based on underlying cause of death codes as determined by the rules of the ninth revision of the International Classification of Diseases (ICD-9). Information about the deaths was gathered through informant interviews, physician or coroner questionnaires, and medical record abstraction, and was used to validate the cause of death. Sensitivity, specificity, and positive predictive value of the death certificate classification of CHD death (ICD-9 codes 410-414 and 429.2) were estimated by comparison with the validated cause of death based on physician review of all available information. Results from 9 years of surveillance included a positive predictive value 0.67 (95% CI 0.66-0.68), sensitivity of 0.81 (95% CI 0.79-0.83), and a false-positive rate (1-specificity) of 0.28 (95% CI 0.26-0.30). Comparing CHD deaths as defined by the death certificate with validated CHD deaths indicated that the death certificate overestimated CHD mortality by approximately 20% in the ARIC communities. Within subgroups, death certificate overestimation was reduced with advancing age (up to age 74), was consistent over time, was not dependent on gender, and exhibited considerable variation among communities.     

Peer Reviewed: Overreporting of Deaths From Coronary Heart Disease in New York City Hospitals, 2003

Introduction

New York City has one of the highest reported death rates from coronary heart disease in the United States. We sought to measure the accuracy of this rate by examining death certificates.

Methods

We conducted a cross-sectional validation study by using a random sample of death certificates that recorded in-hospital deaths in New York City from January through June 2003, stratified by neighborhoods with low, medium, and high coronary heart disease death rates. We abstracted data from hospital records, and an independent, blinded medical team reviewed these data to validate cause of death. We computed a comparability ratio (coronary heart disease deaths recorded on death certificates divided by validated coronary heart disease deaths) to quantify agreement between death certificate determination and clinical judgment.

Results

Of 491 sampled death certificates for in-hospital deaths, medical charts were abstracted and reviewed by the expert panel for 444 (90%). The comparability ratio for coronary heart disease deaths among decedents aged 35 to 74 years was 1.51, indicating that death certificates overestimated coronary heart disease deaths in this age group by 51%. The comparability ratio increased with age to 1.94 for decedents aged 75 to 84 years and to 2.37 for decedents aged 85 years or older.

Conclusion

Coronary heart disease appears to be substantially overreported as a cause of death in New York City among in-hospital deaths.     

A study of selected death certificates from three Dublin teaching hospitals

One hundred death certificates were compared over two time periods with the corresponding autopsy reports on the cases to ascertain if the causes of death from the two sources were similar. There was poor concordance between the two and it seems likely that reasons for requesting an autopsy did not extend to using the information to complete the death certificates. There were 55 errors on 45 certificates, and 19 certificates were so inaccurate as to warrant a change in the underlying cause of death. In only 10 cases was the certificate signed before the autopsy report was available; however, should clinicians have wished to add autopsy findings to the certificate later, there is no facility on the Irish death certificate to do so. A revision of the format of the certificate is recommended. An examination of death certificates from varied medical sources would be welcome to see if the serious errors identified in this study are more widespread.     

Autopsy and ill-defined cause of death in the state of S?o Paulo, Brazil]

OBJECTIVE: To investigate the proportion of deaths with an ill-defined cause in the Brazilian state of S?o Paulo between 1980 and 2002, taking into account the influence of autopsies on this proportion. METHOD: Data on the number of deaths were obtained from the Brazilian Ministry of Health. The communities of the state of S?o Paulo were divided into three groups: (1) municipalities with a service to verify the cause of death (and that may conduct an autopsy), (2) municipalities without a cause of death verification service, and (3) the region of Baixada Santista, which had an extremely large increase in the proportion of deaths from ill-defined causes between 1980 and 1995. The impact of autopsies on the proportion of deaths with an ill-defined cause was defined based on the classification made by the first physician evaluating the cause of death, that is, the physician who referred the case to the verification service for autopsy or who completed the death certificate without referring the case to the verification service. Deaths from external causes were excluded, since autopsy is mandatory in these cases. The following were evaluated: (1) proportion of cases classified by the first evaluating physician as having an ill-defined cause, (2) proportion of autopsies in relation to the total number of deaths (except from external causes), and (3) proportion of deaths classified as ill-defined by the first evaluating physician but explained by the autopsy. RESULTS: The proportion of deaths classified by the first evaluating physician as having an ill-defined cause increased over the 1980-2002 period in all three groups studied: the municipalities with a verification service, the municipalities without a verification service, and in the Baixada Santista region. For the state of S?o Paulo overall, the increase was almost 30% over that 1980-2002 period. For the 1998-2002 period, the average proportion of autopsies compared to the total number of deaths (except from external causes) was 21.2% in the municipalities with a verification service, 6.4% in the municipalities without a verification service, and 2.6% in Baixada Santista. The proportion of deaths in 1998-2002 initially classified as having an ill-defined cause but that was explained by autopsy was 92.9% in the municipalities with a verification service, 32.5% in the municipalities without a verification service, and 10.7% in Baixada Santista. CONCLUSIONS: The performance of autopsies accounts for the difference in proportional mortality with an ill-defined cause in the three groups of communities studied. The increase in the number of deaths classified as ill-defined by the first evaluating physician occurring in the state of S?o Paulo over the 1980-2002 period suggests an important decline in the quality of death certificates completed at that first level. More research should be done on the reasons for that change.     

Underreporting of diabetes on death certificates, King County, Washington.

We estimated the reporting of diabetes on death certificates for persons known to have diabetes. Surveillance of 19 hospitals and two paramedic emergency medical services during 12 months in Seattle and King County, Washington, ascertained acute ischemic heart disease events for persons with diabetes and yielded 1235 persons with suspected ischemic heart disease. Mortality was 23.6%, and 41% of death certificates listed diabetes. The reporting of diabetes on the death certificate was not random, and it varied by patient and physician characteristics. Diabetes is strongly linked to fatal ischemic heart disease, but its importance is underrepresented by death certificates for some subgroups.     

Zur Validität der Herz-Kreislauf-Mortalitäts-Statistik der ehemaligen DDR

It has been known already for a long time that in the GDR the mortality rates for coronary heart disease (CHD) and cerebrovascular accidents (CVA) had been considerably underestimated. Instead of these diagnoses very often such general conditions like atherosclerosis and hypertension have been coded as underlying cause of death. We carried out, therefore, two validation studies in order to check whether and to what extent violations of the WHO coding rules were responsible for that. In the first study all hospital deaths which occurred in the GDR between 1985 and 1989 have been compared with the corresponding data of the official mortality statistics (record-linkage-database). In the second study 4.154 death certificates have been manually checked and recoded. Among the hospitalized patients who died from an acute myocardial infraction (AMI) the AMI was coded as underlying cause of death at the death certificate only in 57 % (men) and 54 % (women), respectively. Among cases of CHD these proportions were 66 % and 62 %, respectively, and among cases of CVA 46 % and 44 %, respectively. In the second study among those deaths with AMI as one of the three possible diagnoses at the death certificate AMI was coded as underlying cause of death in men in 46 % and in women in only 30 %. For CHD these proportions were 71 % and 59 %, respectively, and for CVA 44 % and 46 %, respectively. Both studies confirm that in the GDR the selection rules recommended by WHO have often been ignored when coding the death certificates of death cases from AMI, CHD and CVA. Based on the results of the two studies the following correction factors for the official mortality rates are proposed for men and women, respectively: AMI 1.8/2.3; CHD 1.5/1.6; CVA 2.2/2.3.     

Certification of cause of death in Tunisia

We have led a study about 2251 death witch are declared during 1996 in the Great-Tunis. Results are following: The hospital deaths are as many betters certified that the physician is a specialist. The cause mention rate is about 88.6% for death observed by specialists against 28.5% for those observed by internists. Paradoxically, a precise cause mention is best for deaths that are observed outside hospitals and when the physician is an internist. Badly define morbid states represent 17.1% of outside hospitals mentioned causes against 30.8% in the Hospital. They represent 12% of causes mentioned by internist against 30.1% of those mentioned by specialists. Despite death medical certificate obligation, the strong proportion of badly defined morbid states characterizes death causes. We hope that this situation will be improved by the new model usage of the witch will be introduced since 2000. This certificate mentions death causes distinguished in initial, immediate and associated. This certificate has be the object of the decree n degree 99-1043 of 17 may 1999.     

Cause of death: from primary disease to direct cause of death

Following the death of a patient, the treating physician in the Netherlands is required to fill out two forms. Form A, which is the certificate of death and Form B, which is used by the Statistics Netherlands to compile data on causes ofdeath. The latter form often poses difficulty for the physician with respect to the primary cause of death. This applies particularly to cases of sudden death, which account for one third of all deaths in the Netherlands. As a result, the statistical analyses appear to lead to an incorrect representation of the distribution of causes of death. A more thorough investigation into the primary cause of death is desirable, if necessary, supported by a request for an autopsy. The primary cause of death is to be regarded as the basic disease from which the cascade of changes ultimately leading to death originated.     

Decline of acute myocardial infarction death rates not due to cause of death coding

The recent decline in coronary heart disease (CHD) mortality has been attributed to reduction in risk factors, improved management and the possibility of statistical artifacts. The purpose of this study is to assess the impact of geographic and time variation in the coding of cause of death from death certificates into ICD codes upon CHD mortality rates in Canada. Equal samples of death certificates were recoded for Nova Scotia and Saskatchewan for each of the years 1970 and 1984: 1) a first set of 1,600 death certificates originally coded as acute myocardial infarction (AMI) and 2) a second set of 800 death certificates from all causes of death. The coding error rates increased with age and with the number of contributing and underlying causes of death reported on the death certificates. The net effect of false positive and false negative AMI codes on death certificates did not vary significantly by province or year. Thus, variation of death certificate coding over time and geographic regions do not contribute toward the explanation of the AMI mortality rate decline.     

Application of the verbal autopsy during a clinical trial

During a community-based treatment trial of onchocerciasis with ivermectin, verbal autopsies were employed as one method to assess the safety of the drug. The verbal autopsy questionnaire was designed to determine causes of death and mortality differentials in the treated population. During the 8 months of surveillance here reported, 25 individuals died, yet only 9 of these deaths were certified. Seven of the deaths occurred to individuals who had been treated with ivermectin and the majority of the deaths occurred to children under 5, who were excluded from treatment. The verbal autopsy method was evaluated and validated by comparing the verbal autopsy diagnosis of cause of death to death certificate diagnosis, when available. In addition, verbal autopsies were retrospectively performed for all deaths which had occurred at the hospital during the 6 months preceding the start of the study, if these deaths were traceable to households in the surveillance population. We found that in 80% of the adult deaths, the verbal autopsy and death certificate diagnoses of underlying cause of death agreed. The verbal autopsy was less accurate in diagnosing child deaths which we attribute to the design of the verbal autopsy (being to detect potential drug related deaths in adults) and to the delay between death and interview. We conclude that verbal autopsies are an important addition to surveillance systems in remote areas where the absence or inadequacy of health information systems does not allow a thorough follow-up of all subjects in drug studies.     

The validity of revised death certificates (ICD-10) for ischemic heart disease in Oita City, Japan

PURPOSE: Mortality statistics have recorded an increased number of deaths from ischemic heart disease (IHD) since death certificates were revised to reflect the International Classification of Diseases, tenth revision (ICD-10) in Japan, in 1995. However, it remains unclear whether the validity of IHD diagnosis improved after this revision. METHODS: We conducted the Oita Cardiac Death Survey to validate IHD certified deaths that occurred among residents aged 25-74 in Oita City, Japan (mean population = 273,000). Of the eligible 342 fatalities, 328 cases (95.0%) were examined by a review of the medical records and/or interviews with physicians. The MONICA criteria were applied and provided a reference standard against which to assess the validity of certified fatal IHD. Sensitivity (Se), positive predictive value (PPV), specificity (Sp) and negative predictive value (NPV) for IHD as the cause of death were analyzed, assuming that all validated IHD deaths were true. Multivariate logistic models were used to determine associations of false positive and false negative cases with sex, age at time of death and place of death. RESULTS: Vital statistics revealed 273 fatalities to be due to cardiac disease, including 143 from acute myocardial infarctions (AMI), 27 from other IHD, 52 from heart failure and 51 from other heart diseases. After validation, 25 'definite fatal AMI' and 71 'possible fatal AMI or IHD death' were identified among all subjects according to the MONICA criteria. In all, Se, PPV, Sp and NPV for IHD certified as the cause of death were 86.5% (95% Cl: 77.6-92.3), 50.3% (42.5-58.1), 64.7% (58.1-70.7), and 92.0% (86.5-95.5), respectively. PPV among persons aged 25-54 years was remarkably decreased. PPV and Sp among out-of-hospital deaths were significantly lower than for in-hospital deaths. Multivariate logistic models revealed out-of-hospital deaths and being aged 25-54 years to be significant predictors of false positive cases (odds ratio (OR) = 2.03, P < 0.001 versus in-hospital deaths and OR = 2.79, P < 0.05 versus ages of 65-74 years, respectively). CONCLUSIONS: Because false positive cases increased among certified IHD deaths after the revision, PPV and Sp percentages decreased. Out-of-hospital deaths and being aged 25-54 years were associated with increased possibility of false positive. Given our findings, IHD deaths in vital statistics may increase due to the tendency of physicians to certify IHD as the cause of death in cases without clear sign suggestive of other causes.     

Factors associated with out-of-hospital coronary heart disease death: the national longitudinal mortality study

PURPOSE: A significant portion of coronary heart disease deaths occur out of the hospital, prior to access to life saving medical care. Improving the immediacy of care could have important impact on coronary mortality. METHODS: The objective of this research is to identify factors associated with the occurrence of out-of-hospital coronary heart disease death as compared with in-hospital. Identification of these factors could lead to additional strategies for rapid treatment of coronary attack symptoms. A large national cohort study with individually identified characteristics was matched to the National Death Index to identify deaths by cause occurring in up to 11 years of follow-up. Approximately 60,000 deaths occurred in the cohort of approximately 700,000 participants aged 25 years or more. Location of death was defined as either in- or out-of-hospital. RESULTS: Among deaths classified as coronary heart disease (CHD), multivariate logistic models of the association between selected demographic and socioeconomic characteristics of individuals prior to death and place of death show that black persons are more likely to die out of hospital, as are persons who live alone or are unmarried, persons at the lowest end of the income distribution, and persons who live in rural areas vs. urban areas. CONCLUSIONS: The factors most strongly associated with a CHD death occurring out-of-hospital as compared with in-hospital are race (black persons are 1.23 times more likely to die out of hospital than white persons, net of demographic and socioeconomic differentials) and living status (persons who are not married are 1.60 times more likely to die out of hospital than persons who are married, net of demographic and socioeconomic characteristics). Attention should be paid to these groups to emphasize the need for rapid attention to the signs of a coronary attack so that rapid and potentially life saving intervention can be implemented.     

Evaluation of the quality of information on the basic cause of death of infants in Rio Grande do Sul (Brazil)

The validity of the official information on the cause of infant deaths was studied in the Brazilian cities of Porto Alegre and Pelotas in 1985. Using data collected for a population-based case-control study of infant mortality due to infectious diseases or malnutrition, a comparison was made between the causes of death reported on the death certificates and those obtained after a careful review of case-notes and a medical interview with the parents of the decreased infants. Official death certificates showed an excess of deaths attribute to bronchopneumonia (ICD 485X) and septicemia (ICD 038.9), and an underestimation of the number of deaths due to diarrheal diseases (ICD 009.1) and of sudden infant deaths (ICD 798.0). The overall rate of agreement between official and revised certificates, in terms of groups of causes of death, was only 27.9%. Lower respiratory infections, which were the leading infectious cause of infant death according to official statistics, were superseded by diarrheal diseases after this revision.     

Accuracy of death certificate diagnosis of intracranial hemorrhage and nonhemorrhagic stroke. The Minnesota Heart Survey

The validity of death certificate diagnosis of stroke and its type as the underlying cause of death was investigated in a sample of in-hospital deaths of possible stroke cases from the Minnesota Heart Survey. The 228 in-hospital deaths in 1970 and the 180 deaths in 1980 had a stroke diagnosis either on hospital discharge records or as the underlying cause of death on the death certificate. Relative to a standardized physician diagnosis, positive predictive values for the death certificate diagnosis in 1970 were 96% for all types of stroke, 59% for intracranial hemorrhage, and 87% for nonhemorrhagic stroke. The respective values in 1980 were 100%, 82%, and 97%. An increase in positive predictive values, particularly for intracranial hemorrhage between 1970 and 1980, was attributed to the increased use of computerized tomography. Sensitivity for the death certificate diagnosis in 1970 was 63% for all types of stroke, 66% for intracranial hemorrhage, and 45% for nonhemorrhagic stroke. The respective sensitivities in 1980 were 70%, 76%, and 58%. The lower sensitivity for nonhemorrhagic stroke as compared with hemorrhagic stroke was due in part to 1) frequent reporting of nonhemorrhagic stroke as a contributing cause of death rather than the underlying cause of death and 2) time from stroke onset to death. Specificity among these possible strokes was high in both years. The low sensitivity of death certificate diagnosis of stroke may reduce estimated relative risks in epidemiologic studies. Nevertheless, since the advent of widespread use of computerized tomography, a death certificate diagnosis of intracranial hemorrhage versus nonhemorrhagic stroke appears to be sufficiently accurate for use in epidemiologic studies of stroke etiology.     

Vibrio vulnificus infection reporting on death certificates: the invisible impact of an often fatal infection.

This study assessed accuracy of (a) recording Vibrio vulnificus infection on death certificates and (b) International Classification of Disease (ICD)-9 codes for V. vulnificus. Patients with microbiologically confirmed V. vulnificus infection were identified as part of co-ordinated surveillance in four USA Gulf Coast states between 1989 and 1993. Of 60 deaths, 51 death certificates were reviewed and V. vulnificus was recorded as the immediate cause of death on 11 (22%). There was no ICD-9 code for V. vulnificus infection, thus no patients had an ICD-9 code indicating V. vulnificus infection. Of 23 certificates where V. vulnificus was recorded on the death certificate, only 5 (22%) were coded for Gram-negative, septicaemia. This study highlights the importance of teaching physicians how to provide epidemiologically meaningful data on death certificates and the need for accurate ICD mortality codes.     

How accurately is euthanasia reported on death certificates in a country with legal euthanasia: a population-based study

Background

Death certificates are the main source of information on the incidence of the direct and underlying causes of death, but may be unsuitable for monitoring the practice of medical assistance in dying, e.g. euthanasia, due to possible underreporting. This study examines the accuracy of certification of euthanasia.

Methods

Mortality follow-back survey using a random sample of death certificates (N?=?6871). For all cases identified as euthanasia we checked whether euthanasia was reported as a cause of death on the death certificate. We used multivariable logistic regression analysis to evaluate whether reporting varied according to patient and decision-making characteristics.

Results

Through the death certificates, 0.7% of all deaths were identified as euthanasia, compared with 4.6% through the mortality follow-back survey. Only 16.2% of the cases identified from the survey were reported on the death certificate. Euthanasia was more likely to be reported on the death certificate where death was from cancer (14% covered), neurological diseases (22%) and stroke (28%) than from cardiovascular disease (7%). Even when the recommended drugs were used or the physician self-labelled the end-of-life decision as euthanasia, euthanasia was only reported on the death certificate in 24% of cases.

Conclusions

Death certificates substantially underestimate the frequency of euthanasia as a cause of death in Belgium. Mortality follow-back studies are essential complementary instruments to examine and monitor the practice of euthanasia more accurately. Death certificate forms may need to be modified and clear guidelines provided to physicians about recording euthanasia to ensure more accurate certification.

     

Reliability of death certificate diagnoses

Consistency between death certificates and clinical records from 5 general hospitals in Kuwait was studied for 470 deaths with the following underlying or associated causes: hypertensive (HYP), ischaemic heart diseases (IHD), cerebrovascular diseases (CVD) and diabetes mellitus (DM). Direct causes were not considered since they are of little interest analytically. Only deaths with definite or most probable ascertainment were included. One cardiologist, who was provided with the WHO criteria and relevant documents on death certification, independently reviewed the records. To test the reviewer's bias and the reliability of his judgement, an adjudication process was effected by having one senior cardiologist re-review a random subsample of 140 records. The two reviewers showed good agreement. Specific diagnoses criteria for deciding the underlying cause of death in multiple morbid conditions by the reviewer were followed. Due to possible reviewer bias, we aimed at measuring the difference between initial certifiers and the reviewer rather than measuring the diagnostic accuracy of initial certifiers in reference to the reviewer. The agreement 'index kappa showed poor agreement between original and revised certificates. The original certificates underestimated CVD as an underlying cause of death by 69.2%, DM by 60%, IHD by 33.5% and HYP by 31.8% in our sample. Associated causes were also consistently underestimated by initial certifiers as compared with the reviewer. This bias calls for basing mortality statistics in Kuwait on hospital death committees' reports rather than on initial certifier death certificates, use of multiple-causes of death instead of one underlying cause and adequate training of the medical profession on the value and process of death certification.