A computer-based method for cause of death classification in stillbirths and neonatal deaths

BACKGROUND: In large-scale epidemiological studies of stillbirths and neonatal deaths a method is needed to replace detailed medical record audits in order to determine the cause of death. METHODS: A computer-based method is presented for determination of the cause of death in stillbirths and in neonatal deaths. It utilizes information in the Swedish medical registries. The study comprises 6044 dead infants born in Sweden from 1983-1990. For each infant the program determines 31 basic characteristics which are important in deciding the cause of death. Based on these characteristics a modified Wigglesworth's classification is used to find the cause of death. The validity of the method was checked by comparing the computer generated information with information obtained by scrutinizing medical records for a 10% representative sample (603 infants). RESULTS: Specificity and sensitivity for each basic characteristic varied, but for the modified Wigglesworth cause of death classification the concordance was 88%. The weakest data refer to intrauterine deaths, where pertinent information was often missing in the medical registries. CONCLUSION: The method can be used for large-scale epidemiological studies.     

Necropsy: a yardstick for clinical diagnoses

An attempt to obtain necropsies on all deaths from a selected group of clinical units resulted in a necropsy rate of 65% (compared with a normal of 30% in these units). The effect of increasing the necropsy rate was to produce a higher rate of confirmation of clinical diagnoses; nevertheless, 15% of main diagnoses and 42% of causes of death were not confirmed. A large proportion of these were deemed by clinicians in consultations with pathologists to be clinically significant. Of main diagnoses considered certain, 10% were not confirmed. The proportion of diagnostic discrepancies was virtually identical in two groups--those in which the clinicial believed he would normally have requested necropsy, and those in which he would not. Thus clinical confidence in the diagnosis is not an adequate assurance of its accuracy. Although in this survey necropsy was requested on almost all cases, permission was refused in many which may be attributed either to resistance by relatives or to an inadequate approach by the medical staff. The proportion of permissions secured by individual units varied from 50% to 92%. This indicates that the nature of the approach to relatives is the more important factor. As present practices do not adequately allow for the detection of a wide range of misdiagnoses and missed diagnoses it is proposed that a "partial audit" would provide a valuable yardstick; clinicians would be asked to obtain permission for necropsy on an agreed proportion (say, 20%) of deaths over and above those cases in which they are particularly interested and would normally request a necropsy.     

Formal retrospective case review and sudden infant death

A review of 24 consecutive sudden infant deaths was undertaken to evaluate the importance of the various stages in the postmortem assessment of such cases. Death in three cases was caused by obvious trauma. Of the remainder, 16 were attributed to sudden infant death syndrome (SIDS), 4 to accidental asphyxia (identified by death scene examination and/or formal case review) and 1 to a lingual thyroglossal duct cyst. Three (14%) of 21 deaths thought to be SIDS after postmortem examination were attributed to asphyxia following subsequent formal case review.     

Numbers of deaths related to intrapartum asphyxia and timing of birth in all Wales perinatal survey, 1993-5

OBJECTIVES: To investigate the relation between the timing of birth and the occurrence of death related to an intrapartum event. DESIGN: Analysis of 107,206 births to Welsh residents in 1993-5, including 608 cases of stillbirth and 407 of neonatal death identified in the all Wales perinatal survey, the cause of death classified with the clinicopathological system. SUBJECTS: 79 normally formed babies stillborn or who died in the neonatal period, birth weight > 1499 g, for whom cause of death was related to an intrapartum event. MAIN OUTCOME MEASURES: Relative risk of death due to an intrapartum event according to the hour, day, and month of birth. RESULTS: Mortality was higher in babies born between 9.00 pm and 8.59 am than in those born between 9.00 am and 8.59 pm; relative risk (95% confidence interval) 2.18 (1.37 to 3.47). July and August births also had a higher death rate than births in other months; relative risk 1.99 (1.23 to 3.23). Weekened births had a higher death rate but it was not significant. CONCLUSIONS: The excess of deaths at night and during months when annual leave is popular may indicate an overreliance on inexperienced staff at these times. Errors of judgement may also be related to physical and mental fatigue, demanding a more disciplined systematic approach at night. Mistakes may be ameliorated by increasing shiftwork, but shifts should be carefully designed to avoid undue disruption of circardian rhythms. In addition, greater supervision by senior staff may be required at night and during summer months.     

A record-linkage study on risk factors for cause-specific infant mortality

Infant death certificates were linked with birth certificates for infants born to residents of Tohoku, Tokai and Kyushu regions in 1989 (n = 409, 679, or about one-third of all births in Japan), to examine the effects of variables, as reported on birth certificates, on cause-specific infant mortality. "Certain conditions originating in the perinatal period" and "congenital anomalies" accounted for nearly 90 percent of neonatal deaths, while "congenital anomalies", "injuries and poisoning" and "sudden infant death" were responsible for about 65 percent of postneonatal deaths. Mortality rates for almost all causes of infant deaths, except injuries and poisonings, increased as birth weight decreased not only in the neonatal period but also in the postneonatal period. This suggests that low birth weight places some infants at higher risk of death, and conditions that lead to low birth weight independently contribute to the risk of infant death. Cox's proportional hazards linear model was used to assess the effects of variables on infant mortalities by causes of death. An extremely strong birth weight effect was noted for "certain conditions originating in the perinatal period" and "congenital anomalies". Being a male infant and late order of birth in multiparity were other risk factors for deaths from "congenital anomalies", while being a male infant, resident of Tohoku region and maternal stillbirth experience related to deaths from "certain conditions originating in the perinatal period". Elevated risks of sudden infant death syndrome (SIDS), of which mortality rate in Japan was considerably lower than those in most developed Western countries, i.e. 0.23 per 1,000 live births in 1989, were associated with low birth weight, being a male infant, low maternal age, late order of birth in multiparity and illegitimacy. Low maternal age, late order of birth in multiparity and illegitimacy, also, related significantly to increased risk of infant deaths for "injuries and poisoning". These results suggest the independent contributions of socioeconomic factors to infant mortality, especially postneonatal mortality, from SIDS, "injuries and poisonings".     

ST segment elevation induced by class IC antiarrhythmic agents: underlying electrophysiologic mechanisms and insights into drug-induced proarrhythmia

Large-scale analyses of causes of neonatal deaths are usually based on death-certificate information. A new computer-based method has been introduced to define the cause of stillbirths and neonatal deaths in large amounts of material and to classify them according to two different models [Wigglesworth and Neonatal and Intrauterine death Classification according to (a)Etiology (NICE)]. The method is based on a combination of detailed information from health care registries and the death-certificate information. The present study aimed to compare these two classification models with a previously published method based solely on death certificate information [International Collaborative Effort (ICE)]. The study population comprised 2378 neonatal deaths in Sweden between 1987 and 1992. Cross-tabulation was made between the ICE classification and the other two classification models. In addition, case examples are presented in detail, exemplifying how classification errors arose. The ICE classification gives a rather low precision, notably for two important causes of death: asphyxia and immaturity. Among 328 infants dying from asphyxia according to computerized Wigglesworth classification, ICE classified 59% as asphyxia and 22% were labelled immaturity. When ICE classified the deaths as due to asphyxia, this was verified in only 50%. Among 792 infants dying from immaturity according to computerized Wigglesworth classification, 64% were classified as such by ICE. The findings cast doubts on the results of studies based exclusively on death-certificate information. Whenever possible in the analysis of neonatal deaths, death-certificate information should be supplemented with more detailed data. The computer-based method introduced here makes such analyses possible for large databases.     

High prevalence of acute myocardial damage in a hospital necropsy series, shown by C9 immunohistology

AIMS: To use a sensitive test of acute myocardial damage--immunohistological detection of complement component C9--to assess the prevalence of damage in an unselected series of hearts taken at necropsy in adults. METHODS: Sections of formalin fixed and paraffin wax embedded myocardium were cut from 128 consecutive necropsy cases on which a block of heart had been taken. These were stained with an immunohistological method for C9. Necropsy findings were reviewed and clinical risk factors for myocardial damage noted. The extent of C9 immunostaining was correlated with clinical and pathological findings. RESULTS: There was immunostaining for C9 in 109 heart sections (85%). Most had conventional evidence of coronary artery disease or acute or chronic myocardial abnormality, but necrosis was identified by orthodox microscopy in only 12 (11% of C9 positive cases). In 29 cases, orthodox examination showed no abnormality, but C9 was detected. These cases had clinical risk factors for damage such as hypoxia and hypotension. Increasing age, heart weight, and total number of risk factors and pathological findings were associated with increasing extent of C9 immunostaining. CONCLUSIONS: Acute myocardial damage was common in a hospital necropsy series and its prevalence was underestimated by conventional pathological techniques. Immunostaining for C9 was a simple and useful way of detecting such damage.     

Molecular characterization of low-molecular-weight component protein, Flp, in Actinobacillus actinomycetemcomitans fimbriae

OBJECTIVE: To demonstrate the use of aggregated, locally collected birth notification data to examine trends in birth-weight specific survival for singleton and multiple births. DESIGN: Retrospective analysis of 171,527 notified births and subsequent infant survival data derived from computerised community child health records. Validation of data completeness and quality was undertaken by comparison with birth and death registration records for the same period. SETTING: Notifications of births in 1989-1991 to residents of the North Thames (East) Region (formerly North East Thames Regional Health Authority). OUTCOME MEASURES: Birthweight specific stillbirth, neonatal, and postneonatal death rates. RESULTS: There was close correspondence between the notification and registration data. For 96% of the registered deaths a birth notification record was identified and for the majority of these the death was already known to the Community Child Health Computer. Completeness of birth-weight data, particularly at the lower end of the range, was substantially better in birth notification data. Comparison with the most recent published national data relating to birthweight specific survival of very low birthweight singleton and multiple births suggests that the downward trend of mortality is continuing, at least in this Region. CONCLUSIONS: The use of routinely collected aggregated birth notification data provides a valuable adjunct to existing sources of information about perinatal and infant survival, as well as other information regarding process and outcome of maternity services. Such data are required for comparative audit and may be more complete than that obtained from registration or hospital generated data.     

Undetectable maternal serum unconjugated estriol levels in the second trimester: risk of perinatal complications associated with placental sulfatase deficiency

OBJECTIVE: Our purpose was to determine the prevalence of undetectably low second-trimester maternal serum unconjugated estriol levels and the association with increased perinatal morbidity or mortality in pregnancies at risk for placental sulfatase deficiency. STUDY DESIGN: Nine centers in New England identified singleton pregnancies with undetectably low unconjugated estriol levels. Each unexplained case was matched with four controls; pregnancy outcome information was sought. RESULTS: Among 130,295 pregnancies surveyed, undetectably low unconjugated estriol levels were identified in 167 (13/10,000). Explanations included fetal death (53), overestimated gestational age (50), nonpregnancy (12), and chromosome abnormalities (5). The 41 unexplained cases were compared with 163 matched controls. Male offspring were more frequent (85%) among cases than among controls (55%). Although rates of perinatal complications were not significantly different, primary cesarean sections occurred about twice as often among cases. No perinatal deaths occurred. CONCLUSIONS: Neither severity of symptoms nor perinatal morbidity or mortality currently warrant routine interpretation of unexplained undetectably low unconjugated estriol levels as a marker for placental sulfatase deficiency.     

Sudden infant death syndrome

This report is based on a review of the present situation of the sudden infant death syndrome through the presentation of four cases studied at the Unidad de Pediatría, Hospital General de México, S.S.A. All cases were in apparent good health before death. All babies were less than ten months of age. In three cases, necropsy was not performed, and the other one did not show significant abnormalities at the post-mortem examination. A complete review of the literature was made including: historical, epidemiological, genetic, clinical and pathological aspects. Special emphasis is made on the pathophysiology of the syndrome during MOR phase of sleep and muscular hypertrophy of the lungs arteriolae suggesting chronic hypoxia which are the most relevant theories in the sudden infant death syndrome. Psychological aspects and the family management by the physician and detection of possible future victims of the syndrome are finally discussed.     

Effect of maternal cigarette smoking on pregnancy complications and sudden infant death syndrome

BACKGROUND: The purpose of this study was to estimate the annual morbidity and mortality among fetuses and infants that can be attributed to the use of tobacco products by pregnant women. METHODS: Published research reports identified by literature review were combined in a series of meta-analyses to compute pooled risk ratios, which, in turn, were used to determine the population attributable risk. RESULTS: Each year, use of tobacco products is responsible for an estimated 19,000 to 141,000 tobacco-induced abortions, 32,000 to 61,000 infants born with low birthweight, and 14,000 to 26,000 infants who require admission to neonatal intensive care units. Tobacco use is also annually responsible for an estimated 1900 to 4800 infant deaths resulting from perinatal disorders, and 1200 to 2200 deaths from sudden infant death syndrome (SIDS). CONCLUSIONS: Tobacco use is an important preventable cause of abortions, low birthweight, and deaths from perinatal disorders and SIDS. All pregnant women should be advised that smoking places their unborn children in danger. The low success rate of smoking cessation among pregnant women suggests that efforts to reduce the complications of pregnancy attributable to tobacco use by pregnant women should focus on preventing nicotine addiction among teenaged girls.     

1988 National Maternal and Infant Health Survey: methods and response characteristics

OBJECTIVES: The 1988 National Maternal and Infant Health Survey (NMIHS) was conducted by the National Center for Health Statistics to study factors related to poor pregnancy outcome, such as adequacy of prenatal care; inadequate and excessive weight gain during pregnancy; maternal smoking, drinking, and drug use; and pregnancy and delivery complications. METHODS: The NMIHS is a nationally representative sample of 11,000 women who had live births, 4,000 who had late fetal deaths, and 6,000 who had infant deaths in 1988. Questionnaires were mailed to mothers based on information from certificates of live birth, reports of fetal death, and certificates of infant death. Information supplied by the mother, prenatal care providers, and hospitals of delivery was linked with the vital records to expand knowledge of maternal and infant health in the United States. RESULTS: The response rates in all three components of the NMIHS differed according to the mothers' characteristics. Mothers were more likely to respond if they were 20-39 years of age, were white, were married, had fewer than four children, entered prenatal care early, had more prenatal visits, had more years of education, or resided in the Midwest Region. The percent of respondents was lower for teenage mothers, mothers of races other than white, and mothers with four or more children, little prenatal care, or fewer years of education. Mothers whose infants weighed less than 2,500 grams were less likely to respond in the live-birth and infant-death components than mothers whose infants weighed 2,500 grams or more. CONCLUSIONS: The NMIHS will provide an invaluable tool for researchers and practitioners seeking solutions to perinatal and obstetric problems.     

Pathological fear of cot death

Cot death (sudden infant death syndrome) is one of the most common causes of death in the first year of life. Four cases with a pathological fear of cot death are presented. All the patients were depressed and in 2 cases the fear of cot death had an obsessional quality. In all cases there were complications during pregnancy (miscarriage, threatened abortion, recurrent vomiting in last trimester). In 1 case, the patient knew 3 mothers who had suffered cot deaths; in another, the infant was gravely ill in the neonatal period. Pathological fear of cot death can be recognised by the presence of two central features - overvigilance and excessive nocturnal checking of the baby's breathing. Therapeutic interventions are discussed.     

Perinatal death associated with planned home birth in Australia: population based study

OBJECTIVE: To assess the risk of perinatal death in planned home births in Australia. DESIGN: Comparison of data on planned home births during 1985-90, notified to Homebirth Australia, with national data on perinatal deaths and outcomes of home births internationally. RESULTS: 50 perinatal deaths occurred in 7002 planned home births in Australia during 1985-90: 7.1 per 1000 (95% confidence interval 5.2 to 9.1) according to Australian definitions and 6.4 per 1000 (4.6 to 8.3) according to World Health Organisation definitions. The perinatal death rate in infants weighing more than 2500 g was higher than the national average (5.7 versus 3.6 per 1000: relative risk 1.6; 1.1 to 2.4) as were intrapartum deaths not due to malformations or immaturity (2.7 versus 0.9 per 1000: 3.0; 1. 9 to 4.8). More than half (52%) of the deaths were associated with intrapartum asphyxia. CONCLUSIONS: Australian home births carried a high death rate compared with both all Australian births and home births elsewhere. The two largest contributors to the excess mortality were underestimation of the risks associated with post-term birth, twin pregnancy and breech presentation, and a lack of response to fetal distress.     

An assessment of sources of information in post-perinatal infant death reviews

The objective of this study was to identify adverse social and medical factors contributory to post-perinatal deaths and at which stage of the case study each factor was found. The sources of information assessed were: (i) recorded data from case notes, laboratory and postmortem findings, and (ii) created information from (a) home interview and (b) case discussion held in the family doctor's office. The deaths were categorized into seven clinicopathological groups and adverse factors into general demographic and personal psychosocial. Among the 87 sequential post-perinatal infant deaths, 325 adverse factors were identified; of these, 125 (38%) were judged to be actionable by the carers. Of 183 (56%) adverse factors found in the case notes, only 36 were actionable. Forty-five more adverse factors were found at home interview; 26 (58%) of these were actionable. At case discussion another 97 adverse factors were revealed; 63 (65%) were actionable, thus proving the most important source of actionable information.     

Creating a death register for general practice

General practitioners complete approximately 26% of death certificates themselves but have considerable difficulty obtaining prompt and accurate information about their other patients who die. A random survey of district health authorities in England revealed that all were able to compile death lists but none included general practitioner details. This paper reviews the flow of information on patient deaths and describes a project to assess the feasibility of providing Newcastle general practitioners with comprehensive death registers. With the collaboration of the family health services authority and the district health authority, and with data from the regional perinatal mortality survey the creation each week of complete lists of patient deaths, broken down by general practitioner, is feasible. Death registers allow general practitioners to undertake audit of the quality of death certification and of the care of the recently deceased, and to improve the continuing care of the bereaved.     

Does restricted distribution limit access and coverage of yellow fever vaccine in the United States?

BACKGROUND: While human immunodeficiency virus (HIV)-related causes of death have been well documented in developed countries, in Africa data are scanty and mainly based on autopsy studies from city hospitals which are highly selective and may not represent causes of HIV-associated deaths in the general population. This study, from a rural population, describes the causes of death in HIV-positive people and their HIV-negative controls. METHODS: A natural history cohort comprising HIV-1 infected participants and HIV-negative controls was established in rural Uganda in 1990. Causes of death were determined by reviewing the premorbid clinical and laboratory findings and from information obtained from relatives. Blindness to the deceased's HIV serostatus was maintained throughout. RESULTS: In all, 78 deaths occurred over a 6-year period: 63 deaths occurred in the HIV-positive cases (53 prevalent and 10 incident cases) and 15 deaths in the HIV-negative controls. Of the prevalent cases, 56%, and 9% the incident cases enrolled died, compared with 7% of the HIV-negative controls. Of the 55 HIV-positive cases with sufficient data to establish cause of death, 52 (95%) were assessed as having HIV-associated deaths and 48 (87%) died in WHO stage 4 (AIDS). The main causes of death were wasting syndrome (31%), chronic diarrhoea (22%), cryptococcal meningitis (13%) and chest infection (11%). CONCLUSIONS: Our results represent an unbiased selection of deaths in a rural area. The HIV-positive cases have high death rates and die of HIV-related pathologies. The main causes of death reflect the WHO clinical case definition of AIDS. Cryptococcal meningitis is also a common cause of death in this population.     

Implantable hearing devices for sensorineural hearing loss: a review of the audiometric data

BACKGROUND: Child fatality review (CFR) by interagency teams can contribute to the prevention of childhood deaths. We investigated the potential usefulness of Georgia's CFR, legislated in 1990 primarily to prevent death from child maltreatment, for identifying preventable deaths from injury and sudden infant death syndrome (SIDS). METHODS: Using CFR report data and death certificate data, we examined reviewed and nonreviewed childhood deaths in Georgia in 1991 and examined data by etiology, county, risk factors, and preventability. RESULTS: Injury or SIDS caused 33.2% of childhood deaths in Georgia in 1991; CFR reviewed 29.4% of these. Child fatality review was most sensitive for investigating death from intentional injury (40.5%) and SIDS (35.3%). Review teams reassigned the cause of five deaths (2.0%) to child abuse or neglect. County participation was low (31.4%). Overall, 29.0% of deaths were judged preventable. CONCLUSIONS: Georgia's CFR has potential for identifying preventable childhood deaths. Refinements in the system can increase the number and accuracy of death investigations. By participating in the system, physicians may make meaningful contributions to preventing childhood death in their own communities.     

Epidemiological studies on 321 children with congenital diaphragmatic hernia in China]

Perinatal babies delivered in hospitals with gestation of 28 weeks to seven days after birth were monitored by National Birth Defects Monitoring Network from September 1986 to December 1993 to study the prevalence of congenital diaphragmatic hernia in China and the risk factors contributing to their prognosis. Results showed that 321 cases of congenital diaphragmatic hernia in 4,777,220 perinatal babies were detected with an incidence of 0.7 per ten thousand, a case-fatality ratio of 84.1 percent and, fetal death and stillbirth accounting for 28.1 percent of the total perinatal deaths. There was significant difference in birth weight between perinatal deaths and survival perinatal. And, 54.4 percent of the cases complicated with other congenital deformities and severe deformities in heart, lung and central nervous system accounted for the most proportion of them, which were the most important factors contributing to death. A case-fatality ratio of cases with single malformation was 74.7 percent and that of those with multiple malformation 92 percent, with a statistically significant difference. The cases diagnosed antenatally accounted for 11.3 percent of the total, and multiple malformation accounted for a large proportion of them. It indicated that proportion of antenatal diagnosis for congenital diaphragmatic hernia deformity was lower, and their perinatal case-fatality ratio was higher and their prognosis worse.