Defining a study population using enhanced reporting of Aboriginality and the effects on study outcomes.

INTRODUCTION: The under-reporting of Aboriginal and Torres Strait Islander people on routinely collected health datasets has important implications for understanding the health of this population. By pooling available information on individuals' Aboriginal or Torres Strait Islander status from probabilistically linked datasets, methods have been developed to adjust for this under-reporting. OBJECTIVES: To explore different algorithms that enhance reporting of Aboriginal status in birth data to define a cohort of Aboriginal women, examine any differences between women recorded as Aboriginal and those assigned enhanced Aboriginal status, and assess the effects of using different reported populations to estimate within-group comparisons for Aboriginal people. METHODS: Three algorithms, with different levels of inclusiveness, were used to establish different study populations all of which aimed to include all singleton babies born to Aboriginal or Torres Strait Islander women residing in New South Wales, Australia between 2010 and 2014 and their mothers. The demographics of the four study populations were described and compared using frequencies and percentages. In order to assess the impact on research outcomes and conclusions of using study populations derived from different algorithms, estimates of the associations between smoking during pregnancy and selected perinatal outcomes were compared using rates and relative risks. RESULTS: Women included in the study population through enhanced reporting were older, less disadvantaged and more commonly resided in urban areas than those recorded as Aboriginal in the birth data. Although rates of smoking and some perinatal outcomes differed between the different study populations, the relative risks of each outcome comparing smoking and non-smoking Aboriginal mothers were very similar when estimated from each of the study populations. CONCLUSIONS: This work provides evidence that estimates of within-group relative risks are reliable regardless of the assumptions made for establishing the study population through the enhanced reporting of indigenous peoples.

A composite neonatal adverse outcome indicator using population-based data: an update.

INTRODUCTION: Severe morbidity rates in neonates can be estimated using diagnosis and procedure coding in linked routinely collected retrospective data as a cost-effective way to monitor quality and safety of perinatal services. Coding changes necessitate an update to the previously published composite neonatal adverse outcome indicator for identifying infants with severe or medically significant morbidity. OBJECTIVES: To update the neonatal adverse outcome indicator for identifying neonates with severe or medically significant morbidity, and to investigate the validity of the updated indicator. METHODS: We audited diagnosis and procedure codes and used expert clinician input to update the components of the indicator. We used linked birth, hospital and death data for neonates born alive at 24 weeks or more in New South Wales, Australia (2002-2014) to describe the incidence of neonatal morbidity and assess the validity of the updated indicator. RESULTS: The updated indicator included 28 diagnostic and procedure components. In our population of 1,194,681 live births, 5.44% neonates had some form of morbidity. The rate of morbidity was greater for higher-risk pregnancies and was lowest for those born at 39-40 weeks' gestation. Incidence increased over the study period for overall neonatal morbidity, and for individual components: intravenous infusion, respiratory diagnoses, and non-invasive ventilation. Severe or medically significant neonatal morbidity was associated with double the risk of hospital readmission and 10 times the risk of death within the first year of life. CONCLUSION: The updated composite indicator has maintained concurrent and predictive validity and is a standardised, economic way to measure neonatal morbidity when using population-based data. Changes within individual components should be considered when examining longitudinal data.

Perinatal outcomes following bariatric surgery between a first and second pregnancy: a population data linkage study.

OBJECTIVES: To describe the population of women having bariatric surgery and compare the pregnancy outcomes for women having bariatric surgery with a non-bariatric surgery population having a first and second pregnancy. DESIGN: Population-based record linkage study. SETTING: New South Wales (NSW), Australia. POPULATION: All women aged 15-45 years with a hospital record in NSW (2002-2014) and all women giving birth in NSW (1994-2015; n = 1 606 737 women). METHODS: Pregnancy and birth outcomes were compared between first and second pregnancies using repeated-measures logistic regression and paired Student's t-tests. Bariatric and non-bariatric groups were also compared. MAIN OUTCOME MEASURES: Maternal diabetes, preterm birth (<37 weeks of gestation) and large for gestational age. RESULTS: There was a 13-fold increase in hospitalisations for primary bariatric surgery during 2002-2014. Compared with the general birthing population, women who had bariatric surgery experienced higher rates of hypertension, diabetes, and preterm birth. Among women who had bariatric surgery between a first and second pregnancy, there were reduced rates of hypertension (OR 0.39, 95% CI 0.29-0.53), spontaneous preterm birth (OR 0.37, 95% CI 0.16-0.86), infants that were large for gestational age (OR 0.63, 95% CI 0.44-0.88), and the admission of infants to a special care nursery or neonatal intensive care (OR 0.64, 95% CI 0.46-0.90) in the second pregnancy. Rates for small-for-gestational age and gestational diabetes following surgery were 8.3 and 11.4%, respectively CONCLUSIONS: Bariatric surgery between a first and second pregnancy was associated with reductions in obesity-related adverse pregnancy outcomes. Bariatric surgery performed for the management of obesity in accordance with current clinical criteria is associated with improved pregnancy outcomes in a subsequent pregnancy. TWEETABLE ABSTRACT: Bariatric surgery for obesity may improve pregnancy and birth outcomes in a subsequent pregnancy.

Stillbirth rates among Indigenous and non-Indigenous women in Queensland, Australia: is the gap closing?

OBJECTIVE: To determine whether the disparity gap is closing between stillbirth rates for Indigenous and non-Indigenous women and to identify focal areas for future prevention efforts according to gestational age and geographic location. DESIGN: Population-based retrospective cohort study. SETTING: Queensland, Australia. POPULATION: All singleton births of at least 20 weeks of gestation or at least 400 g birthweight. METHODS: Routinely collected data on births were obtained for the period 1995 to 2011. Indigenous and non-Indigenous stillbirth rates and percent reduction in the gap were compared over time and by geographic location and gestational age. MAIN OUTCOME MEASURES: All-cause and cause-specific stillbirth rates (per 1000 ongoing pregnancies). RESULTS: Over the study period there was a 57.3% reduction in the disparity gap. Although marked reductions in the gap were shown for women in regional (57.0%) and remote (56.1%) locations, these women remained at increased risk compared with those in urban regions. There was no reduction for term stillbirths. Major conditions contributing to the disparity were maternal conditions (diabetes) (relative risk [RR] 3.78, 95% confidence intervals [95% CI] 2.59-5.51), perinatal infection (RR 3.70, 95% CI 2.54-5.39), spontaneous preterm birth (RR 3.08, 95% CI 2.51-3.77), hypertension (RR 2.22, 95% CI 1.45-3.39), fetal growth restriction (RR 1.78, 95% CI 1.17-2.71) and antepartum haemorrhage (RR 1.58, 95% CI 1.13-2.22). CONCLUSIONS: The gap in stillbirth rates between Indigenous and non-Indigenous women is closing, but Indigenous women continue to be at increased risk due to a number of potentially preventable conditions. There is little change in the gap at term gestational ages.

Uptake of the Perinatal Society of Australia and New Zealand perinatal mortality audit guideline.

BACKGROUND: Deficiencies in investigation and audit of perinatal deaths result in loss of information thereby limiting strategies for future prevention. The Perinatal Society of Australia and New Zealand (PSANZ) developed a clinical practice guideline for perinatal mortality in 2004. AIMS: To determine the current use and views of the PSANZ guideline, focussing on the investigation and audit aspects of the guideline. METHODS: A telephone survey was conducted of lead midwives and doctors working in birth suites of maternity hospitals with over 1000 births per annum in Australia and New Zealand. RESULTS: Sixty-nine of the 78 eligible hospitals agreed to participate. A total of 133 clinicians were surveyed. Only 42% of clinicians surveyed were aware of the guideline; more midwives than doctors were aware (53 vs 28%). Of those, only 19% had received training in their use and 33% reported never having referred to them in practice. Implementation of even the key guideline recommendations varied. Seventy per cent of respondents reported regularly attending perinatal mortality audit meetings; midwives were less likely than doctors to attend (59 vs 81%). Almost half (45%) of those surveyed reported never receiving feedback from these meetings. The majority of clinicians surveyed agreed that all parents should be approached for consent to an autopsy examination of the baby; however, most (86%) reported the need for clinician training in counselling parents about autopsy. CONCLUSIONS: Effective implementation programmes are urgently required to address suboptimal uptake of best practice guidelines on perinatal mortality audit in Australia and New Zealand.