Weight-specific Mortality Research Articles

Associations of Blood Water Cleared during a Dialysis Session Scaled to Body Surface Area with Weight-Specific Mortality Risk

Associations of Blood Water Cleared during a Dialysis Session Scaled to Body Surface Area with Weight-Specific Mortality Risk

Patient Safety with Fluid Removal with In-Center Hemodialysis.

Fluid management, which is discussed in the article “Ultrafiltration Rate Levels in Hemodialysis Patients Associated with Weight-Specific Mortality Risks,”1 published in this issue of CJASN, has been an aspect of dialysis care that I believe should be the top priority for doctors to manage and has been getting much more attention this past decade. Failure to establish and maintain an appropriate dry weight can lead to serious complications. I would add that if the patient crashes because of dialysis fluid removal and they believe that the treatment itself is causing them pain, it can lead them to miss or shorten treatment or even discontinue vital care. The authors concluded that “ultrafiltration rates associated with various levels of higher mortality risk depend on body weight, but not in a 1:1 ratio, and are different in men versus women, in high–body weight older patients, and in high-vintage patients.”1 As a youth, I had both my kidneys removed as the doctors believed this could help my high BP. After my double nephrectomy, my BP remained very high, and I was hospitalized frequently for it. I was switched to peritoneal dialysis, and within weeks, my BP normalized to 100/70, and I no longer required BP medication. I found myself having to increase my fluid and sodium intake to help maintain my BP. Thankfully, because of either a working kidney transplant or effective fluid management on dialysis, I have not had high BP in decades. Ultrafiltration and fluid removal is a delicate balance, and the goal of hourly fluid ultrafiltration removal is dependent on changes in the intravascular volume. Using volume monitoring, I witnessed my body reacting differently every time I had a hemodialysis treatment, despite the fact that my ultrafiltration goal for my dry weight guestimate was consistent. I could see the difference in my tolerance level if I consumed more sodium in between treatments. It is not surprising to me that weight is a factor in ultrafiltration efficacy. People who maintain higher body weight most likely have a better appetite and may consume more salt, leading them to consume more fluids. Albumin levels would be good to study in comparison and to see if people who have normalized albumin levels tolerate ultrafiltration better. If diabetes is not properly managed, the patient's thirst affects fluid removal goals. In addition, the arbitrary dry weight number the physician sets as a guestimate for dialysis ultrafiltration could change because of hospitalization, changes in eating habits, or other health events. The use of ultrafiltration profiling, in which a predetermined rate of fluid is programmed to be removed per hour, lacks a timely feedback function showing how the patient is tolerating the volume shifts. The feedback is only apparent when the patient has symptoms either of fluid overload or crashing. The kidney community lacks education about crashing on dialysis. When you crash, it does not mean you are at a correct dry weight. The opposite is also true: If you do not have any crashing and have a smooth treatment, this does not mean you are at a correct dry weight. I have heard numerous stories of my peers losing 10–20 pounds of fluid with a functioning kidney transplant within days of surgery. I have experienced great anxiety when my ultrafiltration rate was increased, and I know my peers do as well. Again, the opposite is true: If we think it is too low, we worry about how it will limit our ability to drink fluid in between treatments. It is well documented that people on peritoneal dialysis keep their existing kidney function longer. Preserving existing kidney function plays a big role in our overall health. I was able to keep my existing kidney transplant function for a year during hemodialysis because of the fact that blood volume depletion was monitored and minimized to not dry out my kidney. Ultrafiltration rates can have serious consequences in our overall health. You cannot take too little, and you cannot take too much—you have to take the right amount. Fluid removal is a dynamic process. A sex-, weight-, and vintage patient–indexed ultrafiltration rate measure demonstrates the health disparities of patients on dialysis. However, without an understanding of albumin levels with blood volume changes, along with a patient's overall assessment, it is unclear how this measure will improve patient care or reduce mortality.

Ultrafiltration Rate Levels in Hemodialysis Patients Associated with Weight-Specific Mortality Risks.

We hypothesized that the association of ultrafiltration rate with mortality in hemodialysis patients was differentially affected by weight and sex and sought to derive a sex- and weight-indexed ultrafiltration rate measure that captures the differential effects of these parameters on the association of ultrafiltration rate with mortality. Data were analyzed from the US Fresenius Kidney Care (FKC) database for 1 year after patient entry into a FKC dialysis unit (baseline) and over 2 years of follow-up for patients receiving thrice-weekly in-center hemodialysis. To investigate the joint effect of baseline-year ultrafiltration rate and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions and constructed contour plots of weight-specific mortality hazard ratios over the entire range of ultrafiltration rate values and postdialysis weights (W). In the studied 396,358 patients, the average ultrafiltration rate in ml/h was related to postdialysis weight (W) in kg: 3W+330. Ultrafiltration rates associated with 20% or 40% higher weight-specific mortality risk were 3W+500 and 3W+630 ml/h, respectively, and were 70 ml/h higher in men than in women. Nineteen percent or 7.5% of patients exceeded ultrafiltration rates associated with a 20% or 40% higher mortality risk, respectively. Low ultrafiltration rates were associated with subsequent weight loss. Ultrafiltration rates associated with a given mortality risk were lower in high-body weight older patients and higher in patients on dialysis for more than 3 years. Ultrafiltration rates associated with various levels of higher mortality risk depend on body weight, but not in a 1:1 ratio, and are different in men versus women, in high-body weight older patients, and in high-vintage patients.

Inferring fetal growth restriction as rare, severe, and stable over time.

Reduced birthweight is a marker of pathologies that impair growth and also decrease survival. However, "fetal growth restriction" remains poorly defined. Assuming that birthweight itself has no causal effect on neonatal mortality, we can estimate the features of pathological fetal growth that would be required to produce the observed pattern of weight-specific mortality. Under the simplest possible scenario, we find that at 39-41 weeks, pathological fetal growth restriction affects only about 0.5% of U.S. births, with a neonatal mortality risk up to 220-fold. This surprising concentration of pathology among a tiny subset of babies would account for roughly half of neonatal deaths at term. Moreover, the prevalence of these pathological births appears to have remained relatively stable over recent decades, even as neonatal mortality in the U.S. has declined by 90%. In our model, the decline has been driven by the reduction in baseline mortality (i.e., mortality among babies unaffected by growth pathologies), while the relative risk of death among pathologically grown infants has apparently remained stable. Fetal growth restriction is conventionally regarded as common and preventable. In contrast, our observations suggest that pathological fetal growth is rare and constant over time, perhaps the result of unpreventable stochastic errors in embryonic development. Public health strategies may be more effective by setting aside attempts to increase birthweight, and focusing instead on the discovery and support of factors (unrelated to birthweight) that have produced the striking reductions in neonatal mortality over time.

Clinical outcome of preterm babies managed for respiratory distress syndrome using nasal continuous positive airway pressure and surfactant: An experience from Ile-Ife, South-Western Nigeria

Background: Respiratory distress syndrome (RDS) is a common cause of morbidity and mortality among preterm babies. It is caused by a deficiency of surfactant; hence, there is reduced lung compliance and increased work of breathing. The use of continuous positive airway pressure (CPAP) ventilation, a noninvasive form of ventilation, as well as the administration of exogenous surfactant, has proven to be very useful in the management of RDS. The use of less invasive techniques in ventilation and administration of surfactant have also been shown to reduce the risk of bronchopulmonary dysplasia and adverse effect of intubation. Objective: The objective is to determine mean oxygen saturation at 1 h, 6 h, and 12 h after commencement of CPAP, the mean values of FiO2 and positive end-expiratory pressure before and after administration of surfactant, and the overall case-fatality rate and birth weight-specific mortality rates. Methods: Study design was a prospective observational study and subjects were inborn babies between 26 and 34 weeks gestation who were managed for RDS with CPAP alone or with additional surfactant. Results: All 104 recruited preterm babies were managed with CPAP. Fifty-six (53.8%) babies also had surfactant administered. The mean weight of the babies was 1.35 (±0.322) kg, and the mean gestational age was 30.95 (±2.24) weeks. Extremely low birth weight (ELBW), very low birth weight (VLBW), and LBW constituted 11.5%, 55.8%, and 32.7% of the study population, respectively. The mean SPO2 before CPAP and 12 h after were 90.93 (±5.39) % and 96.5 (±3.30) %, respectively. The overall case-fatality rate was 18.2%, and birth-weight-specific mortality rates for ELBW, VLBW, and LBW were 58.3%, 15.5%, and 9.7%, respectively. Conclusion: From this study, it is clear that the prompt use of a cost-effective CPAP devices and the administration of surfactant are very effective in reducing morbidity and mortality among VLBW babies. While most local studies focused on the experience with the use of CPAP alone, this study goes further to demonstrate that the use of CPAP and surfactant is more effective in the management of RDS.

Cross-State Differences in the Processes Generating Black-White Disparities in Neonatal Mortality.

The U.S. Black neonatal mortality rate is more than twice the White rate. This dramatic disparity can be decomposed into two components: (1) disparities due to differences in the distribution of birth weights, and (2) disparities due to differences in birth weight-specific mortality. I utilize this distinction to explore how the social context into which infants are born contributes to gaps in mortality between Black and White neonates. I analyze variation in Black-White differences in neonatal mortality across 33 states using 1995-2010 data. For each state, I calculate the contribution of differences in birth weight distribution versus differences in birth weight-specific mortality to the total disparity in mortality between White and Black neonates. Disparities are largely a product of different birth weight distributions between Black and White newborns (mirroring the pattern for the United States as a whole). However, in at least nine states, differences in birth weight-specific mortality make a notable contribution. This pattern is observed even among those from advantaged sociodemographic backgrounds and is driven by differences in mortality among very low birth weight neonates. This calls attention to inequality in medical care at birth as an importantcontributor to racial disparities in neonatal mortality.

High birth weight and perinatal mortality among siblings: A register based study in Norway, 1967-2011.

BackgroundPerinatal mortality according to birth weight has an inverse J-pattern. Our aim was to estimate the influence of familial factors on this pattern, applying a cohort sibling design. We focused on excess mortality among macrosomic infants (>2 SD above the mean) and hypothesized that the birth weight-mortality association could be explained by confounding shared family factors. We also estimated how the participant’s deviation from mean sibling birth weight influenced the association.Methods and findingsWe included 1 925 929 singletons, born term or post-term to mothers with more than one delivery 1967–2011 registered in the Medical Birth Registry of Norway. We examined z-score birth weight and perinatal mortality in random-effects and sibling fixed-effects logistic regression models including measured confounders (e.g. maternal diabetes) as well as unmeasured shared family confounders (through fixed effects models). Birth weight-specific mortality showed an inverse J-pattern, being lowest (2.0 per 1000) at reference weight (z-score +1 to +2) and increasing for higher weights. Mortality in the highest weight category was 15-fold higher than reference. This pattern changed little in multivariable models. Deviance from mean sibling birth weight modified the mortality pattern across the birth weight spectrum: small and medium-sized infants had increased mortality when being smaller than their siblings, and large-sized infants had an increased risk when outweighing their siblings. Maternal diabetes and birth weight acted in a synergistic fashion with mortality among macrosomic infants in diabetic pregnancies in excess of what would be expected for additive effects.ConclusionsThe inverse J-pattern between birth weight and mortality is not explained by measured confounders or unmeasured shared family factors. Infants are at particularly high mortality risk when their birth weight deviates substantially from their siblings. Sensitivity analysis suggests that characteristics related to maternal diabetes could be important in explaining the increased mortality among macrosomic infants.

Neonatal and Infant Mortality in Korea, Japan, and the U.S.: Effect of Birth Weight Distribution and Birth Weight-Specific Mortality Rates.

Difference in crude neonatal and infant mortality rates (NMR and IMR) among different countries is due to the differences in its two determinants: birth weight distribution (BWD) and birth weight-specific mortality rates (BW-SMRs). We aimed to determine impact of BWD and BW-SMRs on differences in crude NMR and IMR among Korea, Japan, and the U.S. Our study used the live birth data of the period 2009 through 2010. Crude NMR/IMR are the lowest in Japan, 1.1/2.1, compared to 1.8/3.2, in Korea, and 4.1/6.2, in the U.S., respectively. Japanese had the best BW-SMRs of all birth weight groups compared to the Koreans and the U.S. The U.S. BWD was unfavorable with very low birth weight (< 1,500 g) rate of 1.4%, compared to 0.6% in Korea, and 0.8% in Japan. If Koreans and Japanese had the same BWD as in the U.S., their crude NMR/IMR would be 3.9/6.1 for the Koreans and 1.5/2.5 for the Japanese. If both Koreans and Japanese had the same BW-SMRs as in the U.S., the crude NMR/IMR would be 2.0/3.8 for the Koreans and 2.7/5.0 for the Japanese. In conclusion, compared to the U.S., lower crude NMR or IMR in Japan is mainly attributable to its better BW-SMRs. Koreans had lower crude NMR and IMR, primarily from its favorable BWD. Comparing crude NMR or IMR among different countries should include further exploration of its two determinants, BW-SMRs reflecting medical care, and BWD reflecting socio-demographic conditions.

Developing a standard approach to examine infant mortality: findings from the State Infant Mortality Collaborative (SIMC).

States can improve pregnancy outcomes by using a standard approach to assess infant mortality. The State Infant Mortality Collaborative (SIMC) developed a series of analyses to describe infant mortality in states, identify contributing factors to infant death, and develop the evidence base for implementing new or modifying existing programs and policies addressing infant mortality. The SIMC was conducted between 2004 and 2006 among five states: Delaware, Hawaii, Louisiana, Missouri, and North Carolina. States used analytic strategies in an iterative process to investigate contributors to infant mortality. Analyses were conducted within three domains: data reporting (quality, reporting, definitional criteria, and timeliness), cause and timing of infant death (classification of cause and fetal, neonatal, and postneonatal timing), and maturity and weight at birth/maturity and birth weight-specific mortality. All states identified the SIMC analyses as useful for examining infant mortality trends. In each of the three domains, SIMC results were used to identify important direct contributors to infant mortality including disparities, design or implement interventions to reduce infant death, and identify foci for additional analyses. While each state has unique structural, political, and programmatic circumstances, the SIMC model provides a systematic approach to investigating increasing or static infant mortality rates that can be easily replicated in all other states and allows for cross-state comparison of results.

Improvements in birth weight-specific neonatal mortality rates in the state of Qatar between 2003 &amp; 2010 and a comparative analysis with the Vermont Oxford Network database report of 2007: A pearl study review

Objective:The study aimed to develop a national reference on birth weight-specific neonatal survival in the State of Qatar to facilitate parental counseling.Study Design:This was a retrospective, analytic, and comparative study.Materials and Methods:The birth weight-specific neonatal mortality data for the years 2003 and 2010, collected from the admission and discharge registers of the neonatal intensive care unit, were stratified using the stratifications given in Vermont Oxford Network (VON) 2007 annual report. Category-wise birth weight-specific mortality and relative risk (RR) of death were compared between Qatar data (2003 and 2010) and VON 2007 report.Results:Qatar's neonatal mortality rate (NMR) dropped from 5 of 1000 in 2003 to 4.4 of 1000 in 2010 (P=0.443) which was significant for birth weight categories 501–750 g and 751–1000 g (P=0.026 and P=0.05, respectively). Qatar's NMR in 2010 was significantly lower than VON's NMR during 2007 (P<0.001) though VON's NMR was significantly lower among birth weight categories 751–1000 g and 1001–1500 g (P=0.001 and P=0.003, respectively). The RR of mortality decreased with increasing birth weight. The decline was very sharp for birth weight categories between 500 and 1500g. The RR was 25 times higher in babies with birth weight less than 750 g as compared to babies with birth weight ≥ 2550 g, both in Qatar and VON data. For birth weight categories 751–1000 g and 1001–1500 g, the RR was twice in Qatar as compared to the VON report (16.8 versus 7.8, and 5.5 versus 2.7, respectively).Conclusions:Qatar's current overall and birth weight-specific NMRs are comparable with the VON report except in birth weight categories 751–1000 g and 1001–1500 g which were higher in Qatar. This needs further in-depth qualitative analysis.

The effects of birth weight and gender on neonatal mortality in north central Nigeria

BackgroundWorldwide 15.5% of neonates are born with low birth weight, 95.6% of them in the developing countries. Prematurity accounts for 10% of neonatal mortality globally. The purpose of this study was to evaluate the effects of birth weight and gender on neonatal outcome.FindingsThe data of 278 neonates managed in the Special Care Baby Unit (SCBU) of Jos University Teaching Hospital (JUTH) over a 2 year period from July 2006 to June 2008 were analyzed.One hundred and fifty nine (57.2%) were males and 119(42.8%) females. There were 87(31.3%) preterm and 191 (68.7%) term babies. Twelve of the babies died. Seven (2.52%) and 5 (1.80%) being males and females respectively. The neonatal mortality rate by gender was not significant (p > 0.05). The neonatal mortality was 25.2 deaths per 1000 live births for boys and 18.0 for girls. The mean birth weights of the preterm and term babies were 1.88 ± 0.47 kg and 3.02 ± 0.50 kg respectively, with a mean gestational age of 30.62 ± 3.65 weeks and 38.29 ± 0.99 weeks respectively.Eighty seven (31.3%) of the babies were of low birth weight, 188(67.6%) were of normal birth weight and 3(1.1%) high birth weight. Of the low birth weight babies, 6(2.2%) were term small for gestational age. Six (2.2%) of the preterm infants had normal birth weight.Eleven of the babies that died were preterm low birth weight. The overall mortality rate was 4.32%. The birth weight specific mortality rate was 126 per 1000 for the preterm low birth weight and 5 per 1000 for the term babies. Birth weight unlike gender is a significant predictor of mortality, mortality being higher in neonates of <2.5 kg (OR = 0.04; 95% Cl 0.005-0.310, p = 0.002) (p = 0.453). Seven (58.3%) and 4(33.3%) of the pre-terms that died were appropriate and large for gestational age respectively. Gestational age is not a significant predictor of neonatal mortality (p = 0.595). Babies delivered at less than 37 weeks of gestation recorded a higher rate of mortality than those of 37 weeks and above (p = 0.000).The subjects showed one or more major clinical indications for admission. The major clinical indications for the preterm and term babies were respectively as follows: neonatal sepsis 63(22.7%) and 124(44.6%); neonatal jaundice 32(11.1%) and 71(24.7%); malaria 9(3.1%) and 13(4.5%); birth asphyxia 3(1.0%) and 7(2.4%). Neonatal sepsis was a common denominator among the babies that died.ConclusionBirth weight unlike gender is a significant predictor of neonatal outcome

Birthweight, preterm birth and perinatal mortality: a comparison of black babies in Tanzania and the USA

Adverse conditions in Africa produce some of the highest rates of infant mortality in the world. Fetal growth restriction and preterm delivery are commonly regarded as major pathways through which conditions in the developing world affect infant survival. The aim of this article was to compare patterns of birthweight, preterm delivery, and perinatal mortality between black people in Tanzania and the USA. Registry-based study. Referral hospital data from North Eastern Tanzania and US Vital Statistics. 14 444 singleton babies from a hospital-based registry (1999-2006) and 3 530 335 black singletons from US vital statistics (1995-2000). Birthweight, gestational age and perinatal mortality. Restricting our study to babies born at least 500g, we compared birthweight, gestational age, and perinatal mortality (stillbirths and deaths in the first week) in the two study populations. Perinatal mortality in the Tanzanian sample was 41/1 000, compared with 10/1 000 among USA blacks. Tanzanian babies were slightly smaller on average (43g), but fewer were preterm (<37 weeks) (10.0 vs. 16.2%). Applying the USA weight-specific mortality rates to Tanzanian babies born at term suggested that birthweight does not play a role in their increased mortality relative to USA blacks. Higher mortality independent of birthweight and preterm delivery for Tanzanian babies suggests the need to address the contribution of other pathways to further reduce the excess perinatal mortality.

Outcome of Low Birth Weight Infants in Diyala Province of Iraq

To measure birth weight-specific mortality rates in the Diyala Province of Iraq and to determine if the causes of neonatal death could identify interventions needed to reduce neonatal mortality rates. We retrospectively compared the outcome of 196 neonates with birth weight 500-2499 g admitted in 2003 with 252 such neonates admitted in 2009. The mortality rate in very low birth weight infant (VLBWI) increased from 12/80 (15%) in 2003 to 51/152 (33.6%) in 2009, (p = 0.003). In LBWI, 10/116 (8.6%) died in 2003 compared to 33/152 (13%) in 2009 (p = 0.29). Sepsis accounted for 35.2% of deaths in VLBWI and 39% in LBWI, Perinatal depression explained 39.2% of deaths in VLBWI and 24.2% in LBWI. The VLBWI mortality in the Diyala province of Iraq doubled in the last 6 years reaching 33.6% in 2009, LBWI mortality increased by 50% reaching 13%. Sepsis and perinatal depression accounted for at least two-third of the deaths.

Intersecting Birth Weight-specific Mortality Curves: Solving the Riddle

Small babies from a population with higher infant mortality often have better survival than small babies from a lower-risk population. This phenomenon can in principle be explained entirely by the presence of unmeasured confounding factors that increase mortality and decrease birth weight. Using a previously developed model for birth weight-specific mortality, the authors demonstrate specifically how strong unmeasured confounders can cause mortality curves stratified by known risk factors to intersect. In this model, the addition of a simple exposure (one that reduces birth weight and independently increases mortality) will produce the familiar reversal of risk among small babies. Furthermore, the model explicitly shows how the mix of high- and low-risk babies within a given stratum of birth weight produces lower mortality for high-risk babies at low birth weights. If unmeasured confounders are, in fact, responsible for the intersection of weight-specific mortality curves, then they must also (by virtue of being confounders) contribute to the strength of the observed gradient of mortality by birth weight. It follows that the true gradient of mortality with birth weight would be weaker than what is observed, if indeed there is any true gradient at all.

Invited Commentary: Crossing Curves--It's Time to Focus on Gestational Age-specific Mortality

For decades, epidemiologists have observed that, among lower birth weight infants, higher risk infants have lower mortality rates than do lower risk infants. However, among higher birth weight infants, the pattern reverses, leading to a riddle of crossing birth weight-specific mortality curves. The riddle has been considered from different perspectives, including relative z scores, directed acyclic graphs, and, most recently, simulated mathematical models of underlying causal factors that produce the observed curves; similarly paradoxical gestational age-specific mortality curves uncross when calculations include all fetuses-at-risk rather than just infants delivered at a particular gestational age. However, researchers have generally focused on birth weight rather than gestational age, likely because birth weight is accurately measured and, if one assumes that birth weight is an intermediate variable between the underlying causal factors and mortality, is easier to model. Within the framework of existing analytical approaches, adding the complexity of a direct relation between gestational age and mortality, and possibly more complex relations among the casual factors, may be difficult. Nevertheless, duration of pregnancy seems a better proxy for the true construct of interest, whether the baby is mature enough to survive, so shifting attention to understanding the riddle of gestational age-specific mortality is encouraged.

Características biológicas e evitabilidade de óbitos perinatais em uma localidade na cidade do Rio de Janeiro, 1999 a 2003

OBJETIVOS: analisar os óbitos perinatais de uma maternidade pública do município do Rio de Janeiro, Brasil, quanto à características biológicas, critérios de evitabilidade, causas básicas e mortalidade por faixas de peso. MÉTODOS: o estudo de coorte foi realizado de 1999 a 2003, na Maternidade Leila Diniz do Hospital Municipal Raphael de Paula Souza, que é responsável por 50% dos partos de uma área programática 4 (Jacarepaguá e Barra da Tijuca). Foram incluídos óbitos perinatais com peso igual ou superior a 500 g. O instrumento principal de coleta de dados foi a Ficha de Investigação de Óbito Perinatal. Foi aplicada a Classificação de Wigglesworth para avaliar evitabilidade. RESULTADOS: houve 512 óbitos perinatais (377 fetais e 135 neonatais precoces). Os óbitos neonatais se concentraram nos primeiros três dias de vida. Vinte e quatro por cento dos óbitos cursaram com retardo de crescimento intra-uterino. As principais causas foram afecções maternas (hipertensão e sífilis) e complicações de membrana, placenta e cordão. Foram considerados evitáveis cerca de 50% dos óbitos. CONCLUSÕES: o percentual de óbitos evitáveis foi elevado, mais concentrado nos óbitos fetais ocorridos antes do parto, sugerindo inadequação do pré-natal.

From causal diagrams to birth weight-specific curves of infant mortality

This report explores the low birth weight paradox using two graphical approaches: causal directed acyclic graphs (DAGs), and the empirical curves of the birth weight distribution and birth weight-specific mortality. The birth weight curves are able to represent the associations quantitatively, while the corresponding causal DAGs provide a set of plausible explanations for the findings. Taken together, these two approaches can facilitate discussion of underlying biological mechanisms.

Assessing fetal growth impairments based on family data as a tool for identifying high-risk babies. An example with neonatal mortality

BackgroundLow birth weight is associated with an increased risk of neonatal and infant mortality and morbidity, as well as with other adverse conditions later in life. Since the birth weight-specific mortality of a second child depends on the birth weight of an older sibling, a failure to achieve the biologically intended size appears to increase the risk of adverse outcome even in babies who are not classified as small for gestation. In this study, we aimed at quantifying the risk of neonatal death as a function of a baby's failure to fulfil its biologic growth potential across the whole distribution of birth weight.MethodsWe predicted the birth weight of 411,957 second babies born in Denmark (1979–2002), given the birth weight of the first, and examined how the ratio of achieved birth weight to predicted birth weight performed in predicting neonatal mortality.ResultsFor any achieved birth weight category, the risk of neonatal death increased with decreasing birth weight ratio. However, the risk of neonatal death increased with decreasing birth weight, even among babies who achieved their predicted birth weight.ConclusionWhile a low achieved birth weight was a stronger predictor of mortality, a failure to achieve the predicted birth weight was associated with increased mortality at virtually all birth weights. Use of family data may allow identification of children at risk of adverse health outcomes, especially among babies with apparently "normal" growth.

Guest Editorial: Biomarkers of Perfluorinated Chemicals and Birth Weight

Guest Editorial: Biomarkers of Perfluorinated Chemicals and Birth Weight

Perinatal Periods of Risk (PPOR): Analysis of Feto-Infant Mortality in Louisville Metro During 2001–2003

Purpose The objective of the present study was to analyze feto-infant mortality rates in Louisville Metro during 2001–2003 to understand specific causes and to interpret disparities using the Perinatal Periods of Risk (PPOR) as a surveillance tool. The study question was: which areas in perinatal health have the highest feto-infant mortality rates in Louisville Metro during the period 2001–2003? Methods The PPOR approach divides feto-infant mortality into four strategic prevention areas: Maternal Health / Prematurity (MHP), Maternal Care (MC), Neonatal care (NC) and Infant Health (IH) based on birth weight and age at death. Category specific infant mortality rates were calculated using linked birth-death files and fetal death records. Excess mortality in Louisville was determined with respect to a national reference population. Kitagawa analysis was used to differentiate between excess mortality due to birthweight distribution and birth weight specific mortality. Determinants for very low birthweight (VLBW) were further analyzed using logistic regression. Results In 2001–2003, feto-infant mortality rate in Louisville Metro was 10.6 per 1000 live births: 9.3 among whites and 14.8 among African Americans. Mortality rates (per 1000) among PPOR categories were: MHP (4.7) > MC (2.4) > IH (2.3) > NC (1.2). Two categories, MHP and IH, accounted for 78 % of excess deaths. Birthweight distribution accounted for 39% of excess mortality in the MHP category; however, there was a 10 % survival advantage due to birthweight specific mortality in MHP category. A two fold excess mortality among African Americans versus whites in the MHP category was due to birthweight distribution. Multiple births followed by medical risk, alcohol consumption and late onset prenatal care were found to be significant risk factors for VLBW. Conclusion More efforts should be targeted to reduce the prevalence of VLBW and to prevent post-neonatal mortality in the Louisville Metro.