Contribution of respiratory tract infections to child deaths: a data linkage study.

BACKGROUND: Respiratory tract infections (RTIs) are an important cause of death in children, and often contribute to the terminal decline in children with chronic conditions. RTIs are often underrecorded as the underlying cause of death; therefore the overall contribution of RTIs to child deaths and the potential preventability of RTI-related deaths have not been adequately quantified. METHODS: We analysed deaths in children resident in England who died of non-injury causes aged 28 days to 18 years between 2001 and 2010 using death certificates linked to a longitudinal hospital admission database. We defined deaths as RTI-related if RTIs or other respiratory conditions were recorded on death certificates or linked hospital records up to 30 days before death. We examined trends in mortality by age group, year and season (winter or summer) and determined the winter excess of RTI-related deaths using rate differencing techniques. We estimated the proportion of RTI-related deaths in children with chronic conditions. RESULTS: 22.4% (5039/22509) of child deaths were RTI-related. RTI-related deaths declined by 2.3% per year in infants aged 28 to 364 days between 2001 and 2010. No decline was observed for older children. On average there were 161 winter excess RTI-related deaths annually, accounting for 32% of all RTI-related deaths. 89.0% of children with RTI-related deaths had at least one chronic condition; neurological conditions were the most prevalent. CONCLUSIONS: RTI-related deaths have not declined in the last decade except in infants. Targeted strategies to prevent the winter excess of RTIs and to treat RTIs in children, particularly children with chronic conditions, may reduce RTI-related deaths.

Linking maternity data for England, 2005-06: methods and data quality.

INTRODUCTION: Maternity Hospital Episode Statistics (HES) data were linked to birth registration and NHS Numbers for Babies (NN4B) data to bring together some key demographic and clinical data items not otherwise available at a national level. This project added to earlier work involving linkage of birth registration records to NN4B records. METHODS: Birth registration and NN4B records were linked to Maternity HES delivery records and also Maternity HES baby records using the NHS Number or other indirect identifiers if NHS Number was missing.Data quality and completeness of Maternity HES were assessed in relation to birth registration data wherever possible. For information not collected at registration, NN4B data were used to validate quality of Maternity HES. RESULTS: Overall, 91 per cent of Maternity HES delivery records could be linked to the birth registration/NHS Numbers for Babies records and 84 per cent of Maternity HES baby records were linked.In 2005 only 3 per cent of Maternity HES records had mother's NHS number missing, compared with 30 per cent in the NN4B dataset. This did not reflect the extent to which Maternity HES data items were missing or discordant. Over a quarter of all linked Maternity HES records for singleton babies had one or more of the following data items missing: birthweight, gestational age, birth status, sex, and date of birth of the baby. On the other hand, for data items where information was stated such as birthweight, birth status, and sex for singleton babies, there was good agreement between Maternity HES and linked birth registration and NN4B data.Although NN4B records the ethnic category of the baby as defined by the mother, and Maternity HES records mother's ethnic category, 87 per cent of the linked records had the same ethnic group. CONCLUSION: Even though a good linkage rate was obtained, the method used will be simplified before data for 2007 are linked. To gain the maximum benefit from this linkage in future years, improvements are urgently needed in the quality and completeness of the data contained in Maternity HES.List of Tables, 55.

Estimating conception statistics using gestational age information from NHS Numbers for Babies data.

Conception statistics routinely published for England and Wales include pregnancies that result in one or more live- or stillbirths (a maternity) or an abortion. All live births are assumed to be 38 weeks gestation as information on gestation is not collected at birth registration. For the first time, gestational age information from the National Health Service (NHS) Numbers for Babies (NN4B) data has been used to re-estimate conception statistics for 2005. This shows that 72 per cent of conceptions leading to a maternity in fact have a gestati on period that differs from 38 weeks and most of these fall at either 37 or 39 weeks. The age-specific conception rates using this revised method are not significantly different to those produced using the current method.

Multivariate analysis of infant death in England and Wales in 2005-06, with focus on socio-economic status and deprivation.

Current health inequality targets include the goal of reducing the differential in infant mortality between social groups. This article reports on a multivariate analysis of risk factors for infant mortality, with specific focus on deprivation and socio-economic status. Data on all singleton live births in England and Wales in 2005-06 were used, and deprivation quintile (Carstairs index) was assigned to each birth using postcode at birth registration. Deprivation had a strong independent effect on infant mortality, risk of death tending to increase with increasing levels of deprivation. The strength of this relationship depended, however, on whether the babies were low birthweight, preterm or small-for-gestational-age. Trends of increasing mortality risk with increasing deprivation were strongest in the postneonatal period. Uniquely, this article reports the number and proportion of all infant deaths which would potentially be avoided if all levels of deprivation were reduced to that of the least deprived group. It estimates that one quarter of all infant deaths would potentially be avoided if deprivation levels were reduced in this way.

Chlorination disinfection by-products and risk of congenital anomalies in England and Wales.

BACKGROUND: Increased risk of various congenital anomalies has been reported to be associated with trihalomethane (THM) exposure in the water supply. OBJECTIVES: We conducted a registry-based study to determine the relationship between THM concentrations and the risk of congenital anomalies in England and Wales. METHODS: We obtained congenital anomaly data from the National Congenital Anomalies System, regional registries, and the national terminations registry; THM data were obtained from water companies. Total THM (< 30, 30 to < 60, > or =60 microg/L), total brominated exposure (< 10, 10 to < 20, > or =20 microg/L), and bromoform exposure (< 2, 2 to < 4, > or =4 microg/L) were modeled at the place of residence for the first trimester of pregnancy. We included 2,605,226 live births, stillbirths, and terminations with 22,828 cases of congenital anomalies. Analyses using fixed- and random-effects models were performed for broadly defined groups of anomalies (cleft palate/lip, abdominal wall, major cardiac, neural tube, urinary and respiratory defects), a more restricted set of anomalies with better ascertainment, and for isolated and multiple anomalies. Data were adjusted for sex, maternal age, and socioeconomic status. RESULTS: We found no statistically significant trends across exposure categories for either the broadly defined or more restricted sets of anomalies. For the restricted set of anomalies with isolated defects, there were significant (p < 0.05) excess risks in the high-exposure categories of total THMs for ventricular septal defects [odds ratio (OR) = 1.43; 95% confidence interval (CI), 1.00-2.04] and of bromoform for major cardiovascular defects and gastroschisis (OR = 1.18; 95% CI, 1.00-1.39; and OR = 1.38; 95% CI, 1.00-1.92, respectively). CONCLUSION: In this large national study we found little evidence for a relationship between THM concentrations in drinking water and risk of congenital anomalies.

Linkage of Maternity Hospital Episode Statistics data to birth registration and notification records for births in England 2005-2014: methods. A population-based birth cohort study.

INTRODUCTION: Maternity Hospital Episode Statistics (HES) data for 2005-2014 were linked to birth registration and birth notification data (previously known as NHS Numbers for Babies or NN4B) to bring together some key demographic and clinical data items not otherwise available at a national level. The linkage algorithm that was previously used to link 2005-2007 data was revised to improve the linkage rate and reduce the number of duplicate HES records. METHODS: Birth registration and notification linked records from the Office for National Statistics ('ONS birth records') were further linked to Maternity HES delivery and birth records using the NHS Number and other direct identifiers if the NHS Number was missing. RESULTS: For the period 2005-2014, over 94% of birth registration and notification records were correctly linked to HES delivery records. Two per cent of the ONS birth records were incorrectly linked to the HES delivery record and 5% of ONS birth records were linked to more than one HES delivery record. Therefore, a considerable amount of time was spent in quality assuring these files. CONCLUSION: The linkage rate for birth registration and notification records to HES delivery records steadily improved from 2005 to 2014 due to improvement in the quality and completeness of patient identifiers in both HES and birth notification data.

Ethnic variation in unexplained deaths in infancy, including sudden infant death syndrome (SIDS), England and Wales 2006-2012: national birth cohort study using routine data.

BACKGROUND: Unexplained deaths in infancy comprise 'sudden infant death syndrome' (SIDS) and deaths without ascertained cause. They are typically sleep-related, perhaps triggered by unsafe sleep environments. Preterm birth may increase risk, and varies with ethnicity. We aimed to compare ethnic-specific rates of unexplained infant death, explore sociodemographic explanations for ethnic variation, and examine the role of preterm birth. METHODS: We analysed routine data for 4.6 million live singleton births in England and Wales 2006-2012, including seven non-White ethnic groups ranging in size from 29 313 (Mixed Black-African-White) to 180 265 (Pakistani). We calculated rates, birth-year-adjusted ORs, and effects of further adjustments on the χ2 for ethnic variation. RESULTS: There were 1559 unexplained infant deaths. Crude rates per 1000 live singleton births were as follows: 0.1-0.2 for Indian, Bangladeshi, Pakistani, White Non-British, Black African; 0.4 for White British; 0.6-0.7 for Mixed Black-African-White, Mixed Black-Caribbean-White, Black Caribbean. Birth-year-adjusted ORs relative to White British ranged from 0.38 (95% CI 0.24 to 0.60) for Indian babies to 1.73 (1.21 to 2.47) for Black Caribbean (χ2(10 df)=113.6, p<0.0005). Combined adjustment for parents' marital/registration status and mother's country of birth (UK/non-UK) attenuated the ethnic variation. Adjustments for gestational age at birth, maternal age and area deprivation made little difference. CONCLUSION: Substantial ethnic disparity in risk of unexplained infant death exists in England and Wales. Apparently not attributable to preterm birth or area deprivation, this may reflect cultural differences in infant care. Further research into infant-care practices in low-risk ethnic groups might enable more effective prevention of such deaths in the general population.

Timing of singleton births by onset of labour and mode of birth in NHS maternity units in England, 2005-2014: A study of linked birth registration, birth notification, and hospital episode data.

BACKGROUND: Maternity care has to be available 24 hours a day, seven days a week. It is known that obstetric intervention can influence the time of birth, but no previous analysis at a national level in England has yet investigated in detail the ways in which the day and time of birth varies by onset of labour and mode of giving birth. METHOD: We linked data from birth registration, birth notification, and Maternity Hospital Episode Statistics and analysed 5,093,615 singleton births in NHS maternity units in England from 2005 to 2014. We used descriptive statistics and negative binomial regression models with harmonic terms to establish how patterns of timing of birth vary by onset of labour, mode of giving birth and gestational age. RESULTS: The timing of birth by time of day and day of the week varies considerably by onset of labour and mode of birth. Spontaneous births after spontaneous onset are more likely to occur between midnight and 6am than at other times of day, and are also slightly more likely on weekdays than at weekends and on public holidays. Elective caesarean births are concentrated onto weekday mornings. Births after induced labours are more likely to occur at hours around midnight on Tuesdays to Saturdays and on days before a public holiday period, than on Sundays, Mondays and during or just after a public holiday. CONCLUSION: The timing of births varies by onset of labour and mode of birth and these patterns have implications for midwifery and medical staffing. Further research is needed to understand the processes behind these findings.

The contribution of gestational age, area deprivation and mother's country of birth to ethnic variations in infant mortality in England and Wales: A national cohort study using routinely collected data.

OBJECTIVES: We aimed to describe ethnic variations in infant mortality and explore the contribution of area deprivation, mother's country of birth, and prematurity to these variations. METHODS: We analyzed routine birth and death data on singleton live births (gestational age≥22 weeks) in England and Wales, 2006-2012. Infant mortality by ethnic group was analyzed using logistic regression with adjustment for sociodemographic characteristics and gestational age. RESULTS: In the 4,634,932 births analyzed, crude infant mortality rates were higher in Pakistani, Black Caribbean, Black African, and Bangladeshi infants (6.92, 6.00, 5.17 and 4.40 per 1,000 live births, respectively vs. 2.87 in White British infants). Adjustment for maternal sociodemographic characteristics changed the results little. Further adjustment for gestational age strongly attenuated the risk in Black Caribbean (OR 1.02, 95% CI 0.89-1.17) and Black African infants (1.17, 1.06-1.29) but not in Pakistani (2.32, 2.15-2.50), Bangladeshi (1.47, 1.28-1.69), and Indian infants (1.24, 1.11-1.38). Ethnic variations in infant mortality differed significantly between term and preterm infants. At term, South Asian groups had higher risks which cannot be explained by sociodemographic characteristics. In preterm infants, adjustment for degree of prematurity (<28, 28-31, 32-33, 34-36 weeks) fully explained increased risks in Black but not Pakistani and Bangladeshi infants. Sensitivity analyses with further adjustment for small for gestational age, or excluding deaths due to congenital anomalies did not fully explain the excess risk in South Asian groups. CONCLUSIONS: Higher infant mortality in South Asian and Black infants does not appear to be explained by sociodemographic characteristics. Higher proportions of very premature infants appear to explain increased risks in Black infants but not in South Asian groups. Strategies targeting the prevention and management of preterm birth in Black groups and suboptimal birthweight and modifiable risk factors for congenital anomalies in South Asian groups might help reduce ethnic inequalities in infant mortality.

Teenage conceptions by small area deprivation in England and Wales, 2001-2002.

This article examines the relationship between teenage conceptions and deprivation in England and Wales in 2001-2002 using data at census ward level. Teenage conceptions are defined as births and abortions to women conceiving under the age of 18. Deprivation has been measured using Carstairs scores rebased using the 2001 Census. For the first time at ward level, analysis has differentiated between births and abortions resulting from teenage conceptions. Findings confirm the strong association between teenage conceptions and deprivation and also that deprivation has a strong influence on the likelihood of conceptions leading to either birth or abortion, although regional variations were observed for this relationship.

Pilot linkage of NHS Numbers for Babies data with birth registrations.

Information about gestational age is important but is not available for live births from registration data. It is, however, collected in NHS Numbers for Babies (NN4B) records. This project investigates the feasibility of linking NN4B data for births in the First quarter of 2005 with birth registration records. Overall 99.8 per cent of NN4B records linked with a registration record. Accuracy of linkage was questioned in 0.9 per cent. Live/stillbirth and multiple birth status were each differently classified in approximately 1 per 1,000 records. Discordance rates for other individual data items ranged from 0.3 per cent for date of birth to 12.9 per cent for postcode. Although needing further investigation, these results justify extending the linkage to the remainder of births in 2005. Linkage would be improved by retaining NHS numbers on stillbirth registration records and avoiding manual transfer of NHS numbers.

Introducing new data on gestation-specific infant mortality among babies born in 2005 in England and Wales.

Gestational age is highly correlated with birth outcomes including birthweight and infant mortality. Since gestational age is not recorded at the registration of live births in England and Wales, it has not been possible to produce routine statistics on gestation-specific infant mortality rates. A new system, introduced in 2002, for allocating NHS numbers at birth (NN4B) provided the opportunity to obtain gestational age information. NN4B records have been linked with birth registration data for all births occurring in 2005, and further linked with registration records for deaths in the first year of life. Thus, for the first time, we produce gestation-specific infant mortality rates for England and Wales as a whole, including in relation to birthweight, multiplicity, age of mother, marital status/registration type, and the National Statistics Socio-Economic Classification.

Identifying Possible False Matches in Anonymized Hospital Administrative Data without Patient Identifiers.

OBJECTIVE: To identify data linkage errors in the form of possible false matches, where two patients appear to share the same unique identification number. DATA SOURCE: Hospital Episode Statistics (HES) in England, United Kingdom. STUDY DESIGN: Data on births and re-admissions for infants (April 1, 2011 to March 31, 2012; age 0-1 year) and adolescents (April 1, 2004 to March 31, 2011; age 10-19 years). DATA COLLECTION/EXTRACTION METHODS: Hospital records pseudo-anonymized using an algorithm designed to link multiple records belonging to the same person. Six implausible clinical scenarios were considered possible false matches: multiple births sharing HESID, re-admission after death, two birth episodes sharing HESID, simultaneous admission at different hospitals, infant episodes coded as deliveries, and adolescent episodes coded as births. PRINCIPAL FINDINGS: Among 507,778 infants, possible false matches were relatively rare (n = 433, 0.1 percent). The most common scenario (simultaneous admission at two hospitals, n = 324) was more likely for infants with missing data, those born preterm, and for Asian infants. Among adolescents, this scenario (n = 320) was more common for males, younger patients, the Mixed ethnic group, and those re-admitted more frequently. CONCLUSIONS: Researchers can identify clinically implausible scenarios and patients affected, at the data cleaning stage, to mitigate the impact of possible linkage errors.

Estimating the prevalence of chronic conditions in children who die in England, Scotland and Wales: a data linkage cohort study.

OBJECTIVES: To estimate the proportion of children who die with chronic conditions and examine time trends in childhood deaths involving chronic conditions. DESIGN: Retrospective population-based death cohort study using linked death certificates and hospital discharge records. SETTING: England, Scotland and Wales. PARTICIPANTS: All resident children who died aged 1-18 years between 2001 and 2010. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the proportion of children who died with chronic conditions according to age group and type of chronic condition. The secondary outcome was trends over time in mortality rates involving chronic conditions per 100,000 children and trends in the proportion of children who died with chronic conditions. RESULTS: 65.4% of 23,438 children (95% CI 64.8%, 66.0%) died with chronic conditions, using information from death certificates. This increased to 70.7% (95% CI 70.1% to 71.3%) if hospital records up to 1 year before death were also included and was highest (74.8-79.9% depending on age group) among children aged less than 15 years. Using data from death certificates only led to underascertainment of all types of chronic conditions apart from cancer/blood conditions. Neurological/sensory conditions were most common (present in 38.5%). The rate of children dying with a chronic condition has declined since 2001, whereas the proportion of deaths affected by chronic conditions remained stable. CONCLUSIONS: The majority of children who died had a chronic condition. Neurological/sensory conditions were the most prevalent. Linkage between death certificate and hospital discharge data avoids some of the under-recording of non-cancer conditions on death certificates, and provides a low-cost, population-based method for monitoring chronic conditions in children who die.

Child deaths due to injury in the four UK countries: a time trends study from 1980 to 2010.

BACKGROUND: Injuries are an increasingly important cause of death in children worldwide, yet injury mortality is highly preventable. Determining patterns and trends in child injury mortality can identify groups at particularly high risk. We compare trends in child deaths due to injury in four UK countries, between 1980 and 2010. METHODS: We obtained information from death certificates on all deaths occurring between 1980 and 2010 in children aged 28 days to 18 years and resident in England, Scotland, Wales or Northern Ireland. Injury deaths were defined by an external cause code recorded as the underlying cause of death. Injury mortality rates were analysed by type of injury, country of residence, age group, sex and time period. RESULTS: Child mortality due to injury has declined in all countries of the UK. England consistently experienced the lowest mortality rate throughout the study period. For children aged 10 to 18 years, differences between countries in mortality rates increased during the study period. Inter-country differences were largest for boys aged 10 to 18 years with mortality rate ratios of 1.38 (95% confidence interval 1.16, 1.64) for Wales, 1.68 (1.48, 1.91) for Scotland and 1.81 (1.50, 2.18) for Northern Ireland compared with England (the baseline) in 2006-10. The decline in mortality due to injury was accounted for by a decline in unintentional injuries. For older children, no declines were observed for deaths caused by self-harm, by assault or from undetermined intent in any UK country. CONCLUSION: Whilst child deaths from injury have declined in all four UK countries, substantial differences in mortality rates remain between countries, particularly for older boys. This group stands to gain most from policy interventions to reduce deaths from injury in children.

Birth outcomes for African and Caribbean babies in England and Wales: retrospective analysis of routinely collected data.

OBJECTIVES: To compare mean birth weights, gestational ages and odds of preterm birth and low birth weight of live singleton babies of black African or Caribbean ethnicity born in 2005 or 2006 by mother's country of birth. DESIGN: Secondary analysis of data from linked birth registration and NHS Numbers for Babies data set. SETTING: Births to women in England and Wales in 2005 and 2006. PARTICIPANTS: Babies of African and Caribbean ethnicity born in England and Wales in 2005-2006, whose mothers were born in African and Caribbean countries or the UK. Birth outcomes for 51 599 singleton births were analysed. MAIN OUTCOME MEASURES: Gestational age and birth weight. RESULTS: Mothers born in Eastern or Northern Africa had babies at higher mean gestational ages (39.38 and 39.41 weeks, respectively) and lower odds of preterm birth (OR=0.80 and 0.65, respectively) compared with 39.00 weeks for babies with mothers born in the UK. Babies of African ethnicity whose mothers were born in Middle or Western Africa had mean birth weights of 3327 and 3311 g, respectively. These were significantly higher than the mean birth weight of 3257 g for babies of the UK-born mothers. Their odds of low birth weight (OR=0.75 and 0.72, respectively) were significantly lower. Babies of Caribbean ethnicity whose mothers were born in the Caribbean had higher mean birth weight and lower odds of low birth weight than those whose mothers were born in the UK. CONCLUSIONS: The study shows that in babies of African and Caribbean ethnicity, rates of low birth weight and preterm birth varied by mothers' countries of birth. Ethnicity and country of birth are important factors associated with perinatal health, but assessing them singly can mask important heterogeneity in birth outcomes within categories particularly in relation to African ethnicity. These differences should be explored further.

Trends of selected malformations in relation to folic acid recommendations and fortification: an international assessment.

BACKGROUND: Two crucial issues relative to the benefits and impact of folic acid in the prevention of birth defects are whether supplementation recommendations alone, without fortification, are effective in reducing the population-wide rates of neural tube defects (NTDs), and whether such policies can reduce the occurrence of other birth defects. Using data from 15 registries, we assessed rates and trends of 14 major defects, including NTDs, in areas with official recommendations or fortification to assess the effectiveness of recommendations and fortification on a wide range of major birth defects. METHODS: We evaluated surveillance data through 2003 on major birth defects from population-based registries from Europe, North America, and Australia. All included ascertainment of pregnancy terminations (where legal). Trends before and after policies or fortification were assessed via Poisson regression and were compared via rate ratios. RESULTS: Significant changes in trends were seen for NTDs in areas with fortification but not in areas with supplementation recommendations alone. For other major birth defects, there was an overall lack of major trend changes after recommendations or fortification. However, some significant declines were observed for select birth defects in individual areas. CONCLUSIONS: Recommendations alone remain an ineffective approach in translating the known protective effect of folic acid in population-wide decline in NTD rates. Fortification appears to be effective in reducing NTDs. The effect on other birth defects remains unclear.