Comparing hospital discharge records with death certificates: Can the differences be explained?

STUDY OBJECTIVE: The quality of mortality statistics is important for epidemiological research. Considerable discrepancies have been reported between death certificates and corresponding hospital discharge records. This study examines whether differences between the death certificate's underlying cause of death and the main condition from the final hospital discharge record can be explained by differences in ICD selection procedures. The authors also discuss the implications of unexplained differences for mortality data quality. DESIGN: Using ACME, a standard software for the selection of underlying cause of death, the compatibility between the underlying cause of death and the final main condition was examined. The study also investigates whether data available in the hospital discharge record, but not reported on the death certificate, influence the selection of the underlying cause of death. SETTING: Swedish death certificates for 1995 were linked to the national hospital discharge register. The resulting database comprised 69 818 people who had been hospitalised during their final year of life. MAIN RESULTS: The underlying cause of death and the main condition differed at Basic Tabulation List level in 54% of the deaths. One third of the differences could not be explained by ICD selection procedures. Adding hospital discharge data changed the underlying cause in 11% of deaths. For some causes of death, including medical misadventures and accidental falls, the effect was substantial. CONCLUSION: Most differences between underlying cause of death and final main condition can be explained by differences in ICD selection procedures. Further research is needed to investigate whether unexplained differences indicate lower data quality.     

Comparing Swedish hospital discharge records with death certificates: implications for mortality statistics

BACKGROUND: The quality of mortality statistics is of crucial importance to epidemiological research. Traditional editing techniques used by statistical offices capture only obvious errors in death certification. In this study we match Swedish hospital discharge data to death certificates and discuss the implications for mortality statistics. METHODS: Swedish death certificates for 1995 were linked to the national hospital discharge register. The resulting database comprised 69 818 individuals (75% of all deaths), 39 872 (43%) of whom died in hospital. The diagnostic statements were compared at Basic Tabulation List level. RESULTS: The last main diagnosis and the underlying cause of death agreed in 46% of cases. Agreement decreased rapidly after discharge. For hospital deaths, the main diagnosis was reported on 83% of the certificates, but only on 46% of certificates for non-hospital deaths. Malignant neoplasms and other dramatic conditions showed the best agreement and were often reported as underlying causes. Conditions that might follow from some other disease were often reported as contributory causes, while symptomatic and some chronic conditions were often omitted. In 13% of cases, an ill-defined main condition was replaced by a more specific cause of death. CONCLUSIONS: There is no apparent reason to question the death certificate if the main diagnosis and underlying cause agree, or if the main diagnosis is a probable complication of the stated underlying cause. However, cases in which the main diagnosis cannot be considered a complication of the reported underlying cause should be investigated, and assessments made of the feasibility and cost-effectiveness of routinely linking hospital records to death certificates.     

Non-referral of unnatural deaths to coroners and non-reporting of unnatural deaths on death certificates in Taiwan: implications of using mortality data to monitor quality and safety in healthcare.

BACKGROUND: Mortality data has often been used to monitor the quality of cardiac care. OBJECTIVE: To investigate the under-reporting of unnatural deaths in mortality data. METHOD: All patients with a main discharge diagnosis of injury (ICD-9-CM code 800-999) who died in 2003 or 2004 were identified through record linkage between hospital discharge claims data and cause of death data in Taiwan. Percentages of unnatural deaths that had been referred to the coroner and in which injury-related information was reported on the death certificate were estimated. RESULTS: Of 4086 known or suspected unnatural deaths, only 57% (2346/4086) were referred to the coroner, and in 71% (2889/4086) injury-related information was reported on the death certificate. The percentages of referral and reporting were lowest for deaths related to complications in medical and surgical care. In deaths related to fracture of the femur and the effects of a foreign body, many doctors report injury-related information on the death certificate but do not refer the certification of cause of death to the coroner. CONCLUSIONS: The sensitivity of using mortality data alone to detect known or suspected unnatural deaths varied according to the types of injury and external causes. Monitoring cause of death data linked with hospital discharge record data could provide a better system for discovering these unnatural deaths.     

Quality of data on myocardial infarction deaths, Brazil

OBJECTIVE: To evaluate the quality of data on acute myocardial infarction deaths from mortality information systems. METHODS: Data on in-hospital acute myocardial infarction mortality collected from database of the Mortality Information System (SIM) and Hospital Information System (SIH), in 2000, were analyzed. Then data collected from medical records from two hospitals affiliated to the Unified Health System (SUS) in Rio de Janeiro, Brazil, were also analyzed. Medical records, death certificates, and hospital admission forms (AIH) were compared using the World Health Organization criteria of acute myocardial infarction diagnosis. Agreement among different sources was analyzed using Cohen's Kappa statistics and intraclass correlation coefficient. RESULTS: In-hospital death registries in SIM are much larger than in SIH/SUS. There were identified three mechanisms that could explain most of the observed discrepancy: missing hospital admission forms (32.9%), different main diagnosis registered in SIH/SUS (19.2%), and under reporting of deaths in hospital admission forms (3.3%). The medical records review could confirm the diagnoses of acute myocardial infarction in 67.1% of all deaths reported in death certificates. The sensitivity of data on acute myocardial infarction deaths in death certificates was about 90% for both health information systems analyzed. CONCLUSIONS: There is a need for actions to improve the quality of data registered in SIH/SUS such as standardization of criteria for issuing hospital admission forms during hospital emergencies and training local staff on registration systems.     

Studies on the reliability of vital and health records: I. Comparison of cause of death and hospital record diagnoses.

Based on computer linkage of death records and hospital discharge abstracts, underlying cause of death and discharge diagnoses are compared for 9,724 Vermont resident in-hospital deaths occurring between 1969 and 1975. The agreement between the diagnoses recorded in the two data systems provides a measure of the reproducibility of recording, abstracting, and coding practices. Using the first three digits of the International Classification of Diseases, the agreement between cause and closest medical record diagnosis was 72 per cent. Concordance declined by patient age and length of hospital stay and varied significantly by coded cause of death. A major source of variation was the hospital of death where agreement levels ranged between 45 and 84 per cent. The latter finding is regarded as a potential starting point for targeting investigation of sources of discrepancy and initiating efforts to improve diagnosis recording and coding in the two record systems. The value of both depends on continuing efforts to improve and maintain data quality.     

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.     

广东省2005-2012年医疗机构死因报告质量分析

目的评估广东省医疗机构死因报告质量,为改进质量和提高数据利用提供依据。方法资料来源于“中国疾病控制信息系统——死因登记报告信息系统”广东省2005-2012年网络报告数据,应用描述性流行病学方法,采用县区报告率、单位报告率、报告及时率、审核率、审核及时率、死因编码错误率、医疗机构死亡报告占人群死亡总数比例、县及以上医疗机构死亡报告占医院总死亡比例等指标,对广东省2005-2012年及各地市2012年死因网络报告质量进行评价分析。结果2005--2012年,广东省死因网络报告数从2005年的35361例增长到2012年的172704例,年报告死亡率从38．65／10万逐年上升到164．55／10万（按常住人口测算）,县区报告率从88．40％上升到100．00％,县以上医疗机构单位报告率从39．40％上升到69．30％,乡镇卫生院／社区医院的单位报告率从14．24％提升到34．70％;县及以上医疗机构报告及时率从55．25％（2007年）提高到85．19％（2012年）,疾控机构的报卡审核率均维持较高水平（94．94％～99．96％）,审核及时率从79．90％（2006年）提高到97．56％（2012年）,而死因编码错误率从36．62％（2005年）下降到8．59％（2012年）。2012年全省户籍死亡网络报告数占全省户籍死亡总数的比例为27．33％,县及以上医院死亡报告数占医院总死亡数的比例为49．46％。2012年县及以上医疗机构报告率以珠海市（100．00％）、东莞（90．91％）和广州（83．80％）较高,另有6市低于60％;乡镇卫生院／社区医院的单位报告率以江门（89．66％）、广州（78．73％）、深圳（73．17％）较高,另有11个地市低于20％;死因编码错误率以肇庆（2．61％）、珠海（5．04％）、广州（5．14％）较低,另有8个地市高于10％;网络报告死亡数占同期总死亡数的比例以珠海（95．23％）、江门（91．09％）、广州（75．60％）和东莞（65．09％）较高,其余17市均低于40％。结论广东省死因网络报告质量呈现启动初期较低,2008年后逐年明显提升的特点。各地市报告水平发展极不平衡,推行全人群死因监测措施的广州、珠海、江门和东莞报告质量明显优于其余17个地市。推行全人群死因报告策略、持续开展基层技术培训、定期的工作督导和报告质量评价是全面提高报告质量的关键措施。     

天津市院内死亡病例漏报及报告质量评价

目的评价天津市2009年院内死亡病例信息报告质量,为进一步完善死因监测工作提供依据。方法分析天津市2009年死因监测网络直报数据及2008年现场漏报调查数据。结果 2009年院内死亡病例前5位死因分别为恶性肿瘤、心脏病、脑血管疾病、呼吸系统疾病、损伤和中毒,与户籍人口中的前5位死因构成顺序有所不同。根本死因编码错误率为0.41%,76.9%的死亡病例其根本死因诊断依据科学、可靠,77.7%的患者死亡后7 d内能够通过网络直报进行报告,99.7%的报告卡能够在网络直报后7 d内得到审核。院内死亡病例存在漏报,漏报率为4.5%,门、急诊漏报率高于住院。结论天津市住院死亡病例死因报告准确、有效,可以正确评估我市住院死亡人群的死因模式;但也存在不足,院内死亡病例的报告和管理仍是今后死因监测工作的重点。     

An international comparison study indicated physicians' habits in reporting diabetes in part I of death certificate affected reported national diabetes mortality

BACKGROUND AND OBJECTIVE: Physicians may find it confusing to decide whether to report diagnoses in part I or part II of the death certificate. The aim of this study was to contrast differences in diabetes mortality through a comparison of physicians' habits in reporting diabetes in part I of death certification among Taiwan, Australia, and Sweden. METHODS: A cross-sectional, intercountry comparison study. We calculated the proportion of deaths with mention of diabetes in which diabetes was reported in part I of the death certificate and the proportion of deaths with mention of diabetes in which diabetes was selected as underlying cause of death. RESULTS: We found that half of the differences in reported diabetes mortality among Taiwan, Australia, and Sweden were due to differences in reporting deaths with mention of diabetes anywhere on the certificate, and half due to differences in proportion of deaths with mention of diabetes in which diabetes was reported in part I of the death certificate. CONCLUSION: Differences in the reporting of diabetes in part I of the death certificate among physicians in Taiwan, Australia, and Sweden was one of the factors that affected differing reported diabetes mortality in Taiwan, Australia, and Sweden.     

Assessing the quality of medical death certification: a case study of concordance between national statistics and results from a medical record review in a regional hospital in the Philippines

Background

Medical certificates of cause of death (MCCOD) issued by hospital physicians are a key input to vital registration systems. Deaths certified by hospital physicians have been implicitly considered to be of high quality, but recent evidence suggests otherwise. We conducted a medical record review (MRR) of hospital MCCOD in the Philippines and compared the cause of death concordance with certificates coded by the Philippines Statistics Authority (PSA).

Methods

MCCOD for adult deaths in Bohol Regional Hospital (BRH) in 2007–2008 and 2011 were collected and reviewed by a team of study physicians. Corresponding MCCOD coded by the PSA were linked by a hospital identifier. The study physicians wrote a new MCCOD using the patient medical record, noted the quality of the medical record to produce a cause of death, and indicated whether it was necessary to change the underlying cause of death (UCOD). Chance-corrected concordance, cause-specific mortality fraction (CSMF) accuracy, and chance-corrected CSMF were used to examine the concordance between the MRR and PSA.

Results

A total of 1052 adult deaths were linked between the MRR and PSA. Median chance-corrected concordance was 0.73, CSMF accuracy was 0.85, and chance-corrected CSMF accuracy was 0.58. 74.8% of medical records were deemed to be of high enough quality to assign a cause of death, yet study physicians indicated that it was necessary to change the UCOD in 41% of deaths, 82% of which required addition of a new UCOD.

Conclusions

Medical records were generally of sufficient quality to assign a cause of death and concordance between the PSA and MRR was reasonably high, suggesting that routine mortality statistics data are reasonably accurate for describing population level causes of death in Bohol. While overall agreement between the PSA and MRR in major cause groups was sufficient for public health purposes, improvements in death certification practices are recommended to help physicians differentiate between treatable (immediate) COD and COD that are important for public health surveillance.

     

Place, time and certified cause of death in people who die after hospital admission for myocardial infarction or stroke

BACKGROUND: Two areas of uncertainty about routine statistics for mortality after hospital admission for myocardial infarction (MI) or stroke are i) whether most deaths occur in the admission episode itself rather than after discharge, and ii) whether most deaths are certified on death certificates as, respectively, MI or stroke. METHODS: Use of linked hospital and mortality statistics to analyse the time, place and certified cause of death in people aged 35-74 after admission for MI or stroke. RESULTS: Of 7,964 deaths within a year of admission for MI, 5,686 (71.4%) occurred within 30 days of admission. Of these, 4,856 (85.4%) occurred during the initial hospital admission. Of 7,070 deaths within a year of admission for stroke, 4,905 (69.4%) were within 30 days, and 4,509 (91.9%) of these occurred during the initial admission. As expected, deaths at longer intervals than 30 days occurred mainly after discharge. Of deaths within 30 days of MI and stroke, 85.2% and 80.0%, respectively, were certified with MI or stroke as the underlying cause of death. CONCLUSION: In-hospital death rates alone, calculated without record linkage to death certificates, would have identified most deaths that occurred within 30 days of admission. Nonetheless, linkage added to completeness of ascertainment even within this time period. Data without linkage are unreliable in identifying deaths at longer time intervals. Routine mortality statistics for MI and stroke, as the underlying cause, reliably included most deaths that occurred within 30 days of admission for each respective disease.     

Government statistics of certified causes of perinatal mortality in Moscow and certain problems with its improvement

While preparing the Ninth Revision of the International Classification of Diseases, Injuries and Causes of Death (1970-1975), the World Health Organisation sought ways of improving the accuracy of statistics of perinatal mortality. A new Certificate of Cause of Perinatal Death, developed for use in all regions of the USSR and introduced there in 1974, was recommended for introduction in other countries. This was based on the reorganised and more clear-cut coding outlined in Chapter XV of ICD-9. Comparison of the perinatal death rates in 1975 with those in 1986 showed a fall from 25 to 20 per 1000 births, with changes in causes related to changes on classification. Cross-tabulation of multiple-cause perinatal death was made possible by coding maternal conditions affecting the fetus or newborn separately from fetal conditions originating in the perinatal period. Analysis of the results of tabulation of multiple-cause perinatal death in Moscow in 1986 proceeded to a proposed structure for a Basic Tabulation List allowing comparisons of the statistics of perinatal mortality.     

Evaluation of death certificate-based surveillance for traumatic brain injury--Oklahoma 2002

OBJECTIVES: Death certificate data are used to estimate state and national incidence of traumatic brain injury (TBI)-related deaths. This study evaluated the accuracy of this estimate in Oklahoma and examined the case characteristics of those persons who experienced a TBI-related death but whose death certificate did not reflect a TBI. METHODS: Data from Oklahoma's vital statistics multiple-cause-of-death database and from the Oklahoma Injury Surveillance System database were analyzed for TBI deaths that occurred during 2002. Cases were defined using the Centers for Disease Control and Prevention (CDC) ICD-10 code case definition. In multivariate analysis using a logistic regression model, we examined the association of case characteristics and the absence of a death certificate for persons who experienced a TBI-related death. RESULTS: Overall, sensitivity of death certificate-based surveillance was 78%. The majority (62%) of missed cases were due to listing "multiple trauma" as the cause of death. Death certificate surveillance was more likely to miss TBI-related deaths among traffic crashes, falls, and persons aged > or = 65 years. After adding missed cases to cases captured by death certificate surveillance, traffic crashes surpassed firearm fatalities as the leading external cause of TBI-related death. CONCLUSIONS: Death certificate surveillance underestimated TBI-related death in Oklahoma and might lead to national underreporting. More accurate and detailed completion of death certificates would result in better estimates of the burden of TBI-related death. Educational efforts to improve death certificate completion could substantially increase the accuracy of mortality statistics.     

Limitations of hospital discharge diagnoses for surveillance of extrinsic allergic alveolitis

Hospital discharge diagnoses were used to identify all inpatient cases of extrinsic allergic alveolitis (EAA) from 1979 to 1982 in New Jersey. Of 170 reported cases, the hospital records of 48 were available for review. Based on published criteria for the diagnosis of EAA, only three cases (6%) could be classified as probable EAA, while 10 (21%) were possible cases, and 34 (73%) were not EAA. Limitations were apparent in the accuracy of discharge coding and also in the accuracy of the physician's diagnosis. These findings should promote caution among investigators using unvalidated reports based on ICD-9 hospital coding of EAA. Implications for reporting of other occupational lung diseases are discussed.     

Estimation of the incidence of pleural mesothelioma according to death certificates in France

BACKGROUND: The number of cases of pleural mesothelioma in France has varied substantially according to methods of assessment. MATERIALS AND METHODS: We collected information from certifying physicians about 316 subjects who died between 1 July 1992 and 30 June 1993 in three regions of France with a cause of death coded as ICD-9 category 163. The ICD codes selected as the cause of death for 178 deaths between 1 January 1987 and 31 December 1992 histologically confirmed and diagnosed as pleural mesothelioma by an expert committee were examined. Finally, we used this information to estimate the number of deaths from pleural mesothelioma in France in 1992. RESULTS: In Part I, 45% (men: 54%; women: 28%) of the cases coded as ICD-9 section 163 were definitely or probably mesothelioma; 18% (men: 16%; women: 21%) possibly mesothelioma; and 37% (men: 30%; women: 51%) other tumors, primarily adenocarcinoma metastases. In Part II, 74% of the confirmed pleural mesotheliomas were coded in category 163 (men: 75%; women: 70%). Extrapolation nationwide indicated that 902 deaths were coded as ICD-9 163 in 1992: 521 cases involved definite or probable mesothelioma and 724 definite, probable, and possible cases. CONCLUSIONS: The analysis of this sample suggests that estimating the number of mesothelioma cases from the cause-of-death statistics may overestimate their incidence, but that death certificates appeared to report the diagnosis of histologically confirmed mesothelioma accurately.     

Government statistics of certified causes of perinatal mortality in Moscow and certain problems with its improvement

Summary. While preparing the Ninth Revision of the International Classification of Diseases, Injuries and Causes of Death (1970–1975), the World Health Organisation sought ways of improving the accuracy of statistics of perinatal mortality. A new Certificate of Cause of Perinatal Death, developed for use in all regions of the USSR and introduced there in 1974, was recommended for introduction in other countries. This was based on the reorganised and more clear-cut coding outlined in Chapter XV of ICD-9. Comparison of the perinatal death rates in 1975 with those in 1986 showed a fall from 25 to 20 per 1000 births, with changes in causes related to changes on classification. Cross-tabulation of multiple-cause perinatal death was made possible by coding maternal conditions affecting the fetus or newborn separately from fetal conditions originating in the perinatal period. Analysis of the results of tabulation of multiple-cause perinatal death in Moscow in 1986 proceeded to a proposed structure for a Basic Tabulation List allowing comparisons of the statistics of perinatal mortality.     

Comparison of self-report, hospital discharge codes, and adjudication of cardiovascular events in the Women's Health Initiative

Limited information is available from large clinical investigations about the agreement among sources of diagnoses for endpoints. The authors used data from the Women's Health Initiative clinical trials and observational study from January 1994 to November 2000 to evaluate the agreement among self-report, hospital discharge codes, and two different levels of physician review of medical records for cardiovascular endpoints. For myocardial infarction, stroke, pulmonary embolism, and venous thrombosis, the agreement of hospital discharge codes or self-report with review by study physicians at clinical centers was substantial (kappa = 0.64-0.84). For coronary revascularization, agreement among these sources of information was substantial to almost perfect (kappa = 0.79-0.92), but for angina, congestive heart failure, and peripheral vascular disease, concordance was only fair to moderate (kappa = 0.37-0.56), indicating that these endpoints remain difficult to classify reliably. Agreement between physician adjudicators at clinical centers and central physician adjudicators was substantial to almost perfect (kappa = 0.67-0.94). The findings also suggest that, for the endpoint of myocardial infarction, physician review of events with hospital discharge codes for angina and congestive heart failure is an important source of validated events, and for stroke, review of all events with cerebrovascular codes is important.