Incremental effectiveness of 23-valent pneumococcal polysaccharide vaccine against pneumonia hospitalisation among Australian Indigenous children: A record linkage study

BACKGROUND

The impact of pneumococcal conjugate vaccines (PCVs) on pneumonia in children is well-documented but data on 23-valent pneumococcal polysaccharide vaccine (PPV23) are lacking. Between 2001 and 2011, Indigenous children in Western Australia (WA) were recommended to receive PPV23 at 18-24 months of age following 3 doses of 7-valent PCV. We evaluated the incremental effectiveness of PPV23 against pneumonia hospitalisation.

METHODS

Indigenous children born in WA between 2001 and 2012 who received PCV dose 3 by 12 months of age were followed from 18 to 60 months of age for the first episode of pneumonia hospitalisation (all-cause and 3 subgroups: presumptive pneumococcal, other specified causes, and unspecified). We used Cox regression modelling to estimate hazard ratios (HRs) for pneumonia hospitalisation among children who had, versus had not, received PPV23 between 18 and 30 months of age after adjustment for confounders.

RESULTS

11,120 children had 327 first episodes of all-cause pneumonia hospitalisation, with 15 (4.6%) coded as presumptive pneumococcal, 46 (14.1%) as other specified causes and 266 (81.3%) unspecified. No statistically significant reduction in all-cause pneumonia was seen with PPV23 (HR 1.11; 95% CI: 0.87-1.43), but the direction of the association differed for presumptive pneumococcal (HR 0.47; 95% CI: 0.16-1.35) and specified (HR 0.89; 95% CI: 0.49-1.62) from unspecified causes (HR 1.13; 95% CI: 0.86-1.49). During the baseline period before PPV23 vaccination (12-18 months), all-cause pneumonia risk was higher among PPV23-vaccinated than unvaccinated children (RR: 1.73; 95% CI: 1.30-2.28).

CONCLUSION

In this high-risk population, no statistically significant incremental effect of a PPV23 booster at 18-30 months was observed against hospitalised all-cause pneumonia or the more specific outcome of presumptive pneumococcal pneumonia. Confounding by indication may explain the slight trend towards an increased risk against all-cause pneumonia. Larger studies with better control of confounding are needed to further inform PPV23 vaccination.

Estimating the excess burden of pertussis disease in Australia within the first year of life, that might have been prevented through timely vaccination

BACKGROUND

Previous Australian studies have shown that delayed vaccination with each of the three primary doses of diphtheria-tetanus-pertussis-containing vaccines (DTP) is up to 50 % in certain subpopulations. We estimated the excess burden of pertussis that might have been prevented if (i) all primary doses and (ii) each dose was given on time.

METHODS

Perinatal, immunization, pertussis notification and death data were probabilistically linked for 1 412 984 infants born in two Australian states in 2000-12. A DTP dose administered >15 days after the recommended age was considered delayed. We used Poisson regression models to compare pertussis notification rates to 1-year of age in infants with ≥1 dose delayed (Aim 1) or any individual dose delayed (Aim 2) versus a propensity weighted counterfactual on-time cohort.

RESULTS

Of all infants, 42% had ≥1 delayed DTP dose. We estimated that between 39 to 365 days of age, 85 (95% CI: 61-109) cases per 100 000 infants, could have been prevented if all infants with ≥1 delayed dose had received their three doses within the on-time window. Risk of pertussis was higher in the delayed versus the on-time cohort, so crude rates overestimated the excess burden (110 cases per 100 000 infants (95% CI: 95-125)). The estimated dose-specific excess burden per 100 000 infants was 132 for DTP1, 50 for DTP2 and 19 for DTP3.

CONCLUSIONS

We provide robust evidence that improved DTP vaccine timeliness, especially for the first dose, substantially reduces the burden of infant pertussis. Our methodology, using a potential outcomes framework, is applicable to other settings.

Effectiveness of 7-Valent Pneumococcal Conjugate Vaccine Against Invasive Pneumococcal Disease in Medically At-Risk Children in Australia: A Record Linkage Study

BACKGROUND

Children with chronic medical conditions are at higher risk of invasive pneumococcal disease (IPD), but little is known about the effectiveness of the primary course of pneumococcal conjugate vaccine (PCV) in these children.

METHODS

A cohort born in 2001-2004 from two Australian states and identified as medically at-risk (MAR) of IPD either using ICD-coded hospitalizations (with conditions of interest identified by 6 months of age) or linked perinatal data (for prematurity) were followed to age 5 years for notified IPD by serotype. We categorized fully vaccinated children as either receiving PCV dose 3 by <12 months of age or ≥1 PCV dose at ≥12 months of age. Cox proportional hazard modeling was used to estimate hazard ratios (HRs), adjusted for confounders, and vaccine effectiveness (VE) was estimated as (1-HR) × 100.

RESULTS

A total of 9220 children with MAR conditions had 53 episodes of IPD (43 vaccine-type); 4457 (48.3%) were unvaccinated and 4246 (46.1%) were fully vaccinated, with 1371 (32.3%) receiving dose 3 by 12 months and 2875 (67.7%) having ≥1 dose at ≥12 months. Estimated VE in fully vaccinated children was 85.9% (95% CI: 33.9-97.0) against vaccine-type IPD and 71.5% (95% CI: 26.6-88.9) against all-cause IPD.

CONCLUSION

This is the first population-based study evaluating the effectiveness of PCV in children with MAR conditions using record linkage. Our study provides evidence that the VE for vaccine-type and all-cause IPD in MAR children in Australia is high and not statistically different from previously reported estimates for the general population. This method can be replicated in other countries to evaluate VE in MAR children.

A134 UES MANOMETRIC PARAMETERS IN ESOPHAGEAL MOTILITY DISORDERS

Background

Upper esophageal sphincter (UES) function may be evaluated manometrically using a solid-state high-resolution manometry (HRM) system, which allows for the measurement of manometric parameters specific to the UES. While many of these parameters have yet to be validated for use in clinical practice, there is some suggestion that there may be an association between esophageal motility and UES function.

Aims

We aimed to identify the relationship between UES manometric variables and high-resolution esophageal manometry (HREM) diagnoses.

Methods

A retrospective analysis of HREM studies was performed between 2019 and 2021. Extraction of esophageal and UES manometric variables were performed. UES manometric values of interest included: mean basal pressure (mmHg), mean residual pressure (mmHg), relaxation time-to-nadir (ms), relaxation duration (ms), and recovery time (ms). Relationships between manometric diagnosis (Chicago Classification version 3) and UES manometric variables were explored. All values are expressed a medians and group means were compared with the non-parametric Mann-Whitney U test.

Results

2119 symptomatic patients underwent HREM over the study period. Manometric diagnoses were achalasia (72 patients), esophagogastric junction outflow obstruction (286), absent contractility (108), distal esophageal spasm (53), jackhammer esophagus (32), and ineffective esophageal motility (694). 886 patients had no specific motility disorder; 643 of whom had ≤ 20% ineffective swallows and were considered symptomatic controls.

Patients with achalasia had significantly higher mean basal pressures (63.2 vs. 54.4, p = .001), mean residual pressure (3.8 vs. -1.9, p < .001), relaxation-time-to-nadir (182.0 vs. 142.0, p = .005), relaxation duration (820.5 vs. 708.0, p < .001) and recovery time (623.0 vs. 562, p < .001) compared to control patients. Among patients with achalasia, the presence of panesophageal pressurization correlated weakly with recovery time (R² .3, p = .03). Patients with ineffective esophageal motility had significantly higher mean basal pressures (61.7 vs. 54.0, p < .001).

Among all patients, patients with incomplete bolus clearance (≥ 30%) had significantly higher UES mean basal pressure (58.9 vs. 54.6, p = .004), mean residual pressure (-.62 vs. -2, p < .001), relaxation duration (724.0 vs. 707.0, p = .014) and recovery time (580 vs. 558.0, p < .001).

Conclusions

Patients with achalasia may have higher basal and residual UES pressures, and slower relaxation compared to patients with normal esophageal motility. This may reflect dynamic changes of the UES in response to obstruction at the esophagogastric junction. Elevated UES pressures are also seen in patients with ineffective esophageal motility, potentially reflecting a response to poor bolus clearance. More work needs to be done to validate these parameters in clinical practice.

Funding Agencies

None

Place of birth and outcomes associated with large volume transfusion: an observational study

BACKGROUND

Guidelines recommend that women at high risk of postpartum haemorrhage deliver at facilities able to handle heavy bleeding. However postpartum haemorrhage is often unexpected. This study aims to compare outcomes and health service use related to transfusion of ≥4 units of red blood cells between women delivering in tertiary and lower level hospitals.

METHODS

The study population was women giving birth in public hospitals in New South Wales, Australia, between July 2006 and December 2010. Data were obtained from linked hospital, birth and blood bank databases. The exposure of interest was transfusion of four or more units of red cells during admission for delivery. Outcomes included maternal morbidity, length of stay, neonatal morbidity and need for other blood products or transfer to higher care. Multivariable regression models were developed to predict need of transfusion of ≥4 units of red cells using variables known early in pregnancy and those known by the birth admission.

RESULTS

Data were available for 231,603 births, of which 4309 involved a blood transfusion, with 1011 (0.4%) receiving 4 or more units. Women giving birth in lower level and/or smaller hospitals were more likely to receive ≥4 units of red cells. Women receiving ≥4 units in tertiary settings were more likely to receive other blood products and have longer hospital stays, but morbidity, readmission and hysterectomy rates were similar. Although 46% of women had no identifiable risk factors early in pregnancy, 20% of transfusions of ≥4 units occurred within this group. By the birth admission 70% of women had at least one risk factor for requiring ≥4 units of red cells.

CONCLUSIONS

Overall outcomes for women receiving ≥4 units of red cells were comparable between tertiary and non-tertiary facilities. This is important given the inability of known risk factors to predict many instances of postpartum haemorrhage.

631Benefits of not smoking during pregnancy for Aboriginal women and their babies

Background

To provide evidence for targeted smoking cessation policy, the aim of this study was to compare pregnancy outcomes of Aboriginal mothers who reported not smoking during pregnancy with those who reported smoking.

Methods

This population-based retrospective cohort study used linked data from routinely collected datasets. Not smoking during pregnancy was the exposure of interest among all New South Wales Aboriginal women who became mothers of singleton babies in 2010–2014. Unadjusted and adjusted relative risks (aRR) and 95%CIs from modified Poisson regression were used to examine associations between not smoking during pregnancy and maternal and perinatal outcomes including severe morbidity, inter-hospital transfer, perinatal death, preterm birth and small-for-gestational age. Population attributable fractions (PAFs) were calculated using adjusted relative risks.

Results

Compared with babies born to mothers who smoked during pregnancy, babies born to non-smoking mothers had a lower risk of all adverse perinatal outcomes including perinatal death (aRR=0.58, 95%CI 0.44–0.76), preterm birth (aRR=0.58, 95%CI 0.53–0.64) and small-for-gestational age (aRR=0.35, 95%CI 0.32–0.39). PAFs(%) were 27% for perinatal death, 26% for preterm birth and 48% for small-for-gestational-age. Compared with women who smoked during pregnancy (n = 8,919), those who did not smoke (n = 9,235) had a lower risk of being transferred to another hospital (aRR=0.76, 95%CI 0.66–0.89).

Conclusions

Babies born to women who did not smoke had much lower risks of all adverse perinatal outcomes.

Key messages

Between a quarter and a half of adverse perinatal outcomes in this population could potentially be prevented by an effective smoking cessation program.

1377Did patient blood management guidelines reduce the rate of blood transfusion in pregnancy?

Background

Concern about increasing transfusion rates, adverse effects and increased costs have led to international efforts to reduce transfusion rates. Australian patient blood management guidelines were first introduced for critical bleeding in 2011, followed by obstetric guidelines in 2015. This study examines obstetric transfusion rates before and after the introduction of the critical bleeding and obstetric guidelines, accounting for pregnancy characteristics and prior trajectories.

Methods

Data were obtained from linked birth and hospital records from NSW between January 2002 and December 2017. Changes in raw and risk adjusted transfusion rates over time were investigated using interrupted time series analysis to assess changes in the trend in rate of transfusion among pregnant women with the introduction of each set of guidelines. Sensitivity analysis was performed to identify patterns in the data independently from the interventions.

Results

Data for 1,477,001 births in NSW from 2002 to 2017 were available for analysis. Preliminary analysis suggests the increasing rate of transfusion from 2002 was flattened after the introduction of the 2011 guidelines, with a significantly decreasing trend observed after the 2015 obstetric guidelines were introduced.

Conclusions

Patient blood management guidelines were associated with a reduction in the rate of obstetric transfusion in NSW.

Key messages

A focus on patient blood management was associated with an approximately 30% reduction in the transfusion rate, compared to the predicted rate, by the end of the study period. Future work will investigate whether this change in transfusion rates is associated with a change in rates of adverse outcomes.

472Long-term effectiveness of 3-dose primary course and 4-year booster dose of pertussis vaccine in Australia

Background

Australia’s National Immunisation Program recommended a 3-dose primary Diphtheria-Tetanus-Pertussis (DTP) vaccination course at 2, 4 and 6 months and a booster dose at 4 years during 2003-2015. We examined vaccine effectiveness by time since doses 3 and 4, as studies to date have shown conflicting results.

Methods

Perinatal, immunisation, pertussis notification and death data were linked for 1,086,319 infants born in two Australian states in 2003-2012. Administration of DTP doses 3 and 4 from 5.5-7 months and 47-53 months respectively, was considered age-appropriate. Adjusted Cox proportional hazards models with time-varying vaccination status were used to estimate vaccine effectiveness (VE = 1–hazard ratio) against notified pertussis post age-appropriate doses 3 and 4 compared to unvaccinated children, with additional benefit of dose 4 compared to receipt of primary course alone.

Results

Dose 3 VE declined from 79% (CI 75%-83%) from 0-6 months to 64% (CI 60%-67%) at 6-36 months and 45% (CI 31%-56%) at 36-42 months post-vaccination. Compared to unvaccinated children, VE after dose 4 declined from 83% (CI 80%-86%) at 0-12 months to 67% (CI 60%-72%) and 55% (CI 46%-63%) in the following two 12-month periods post-vaccination. When compared to dose 3, the relative VE for dose 4 was 58% (CI 51%-64%) in 0-18 months post-vaccination.

Conclusion and Key messages

Our study adds to previous Australian evidence for substantial waning of vaccine induced immunity against pertussis over a 3-year period following dose 3. VE was significantly higher in the 18 months following dose 4 compared to receipt of primary course alone.

473Preventable pertussis burden in Australia within the first year of life by improving vaccination timeliness

Background

Previous Australian studies have shown that on-time Diphtheria-Tetanus-Pertussis (DTP) vaccination coverage is 50-60% in certain subpopulations. We estimated the potentially preventable burden of pertussis if, 1) the full primary course and, 2) each dose was given on-time.

Methods

Perinatal, immunisation, pertussis notification, and death data were linked for 1,412,984 infants born in two Australian states in 2000-2012. A DTP dose administered &gt;15 days after the recommended age was categorised as delayed. For aim 1, pertussis rates up to 1-year of age were compared in infants with ≥1 dose delayed versus all doses on-time, using Poisson regression methods. For aim 2, the expected number of cases preventable by each dose was calculated as the product of the number of cases observed during the period of delay and (1 – dose-specific vaccine effectiveness).

Results

58% of infants had all primary DTP doses on time. We estimated that 85 (95% CI: 61-109) cases per 100,000 infants, aged 39-days to 1-year, could have been prevented if all infants had been vaccinated on time; 77% of these infants had received ≥1 DTP dose within the first year of life. Estimated preventable burden attributable to delayed DTP1 (58/100,000) was higher than for DTP2 (26/100,000) and DTP3 (15/100,000).

Conclusions and Key messages

Poor vaccine timeliness, especially delayed DTP1, is a key contributor to the residual burden of pertussis. These findings can inform cost-benefit analyses of targeted programs and public health messaging to reduce delays.

1467Interaction effects of multimorbidity and frailty on adverse health outcomes in elderly hospitalised patients

Background

Multimorbidity and frailty are each known to be drivers of adverse outcomes, but their joint effects are less well known.

Methods

We used state-wide hospital and mortality data for persons aged ≥75 years, admitted during 2010-2012 in New South Wales, Australia, to ascertain multimorbidity, frailty risk and outcomes: prolonged length of stay (LOS), 30-day mortality and 30-day emergency readmission. We estimated the relative risk (RR) of each outcome using Poisson models with random intercept for hospital. Interactions on both additive and multiplicative scales were examined.

Results

Among 257,535 elderly inpatients, 33.6% had multimorbidity and elevated frailty risk, 14.7% had multimorbidity only, 19.9% had elevated frailty risk only and 31.8% had neither. Additive interactions were present for all outcomes, with a further multiplicative interaction for mortality and LOS. Mortality risk was 4.2 (95% CI 4.1 – 4.4), prolonged LOS 3.3 (95% CI 3.3 – 3.4) and readmission 1.8 (95% CI 1.7 – 1.9) times higher in patients with both factors present compared with patients with neither.

Conclusions

Multimorbidity and frailty coexist in older hospitalized patients and interact to increase the risk of adverse outcomes beyond the sum of their individual effects. Their joint effect should be considered in health outcomes research and when administering hospital resources.

Key messages

Multimorbidity and frailty coexist and interact to increase the risk of adverse outcomes in hospitalised patients. Research and health planners should consider their joint effects to ensure patients at the highest risk of adverse outcomes are identified.

1013How has change in gestational diabetes diagnosis affected pregnancy outcomes?

Background

Gestational diabetes mellitus (GDM) incidence is increasing in Australia, influenced by new diagnostic criteria gradually implemented from 2011. We aimed to identify whether the change was associated with increased obstetric intervention and/or improved outcomes.

Methods

Linked perinatal, hospital and deaths data from New South Wales identified singleton births, 33-41 weeks, 2006-2015. Adjusted Poisson modelling predicted the GDM incidence trajectory post-2011 without the diagnostic change and estimated the post-2011 “additional GDM” cases. Actual rates of interventions and outcomes for GDM-diagnosed pregnancies were compared with predicted scenarios where the “additional GDM” group was assumed to have the same rate as (ie clinically same as): (A) the “previous GDM” group &lt;2011; (B) the “non-GDM” group &lt;2011; or (C) the “non-GDM” group ≥2011.

Results

GDM incidence more than doubled over the study period. Actual planned birth, Caesarean and macrosomia rates were consistent with Scenario A, ie higher intervention rates, but lower macrosomia than B and C. Neonatal hypoglycaemia was lower than Scenario A, closer to B and C. Actual perinatal deaths were lower than predicted by all scenarios, showing improvement for all with GDM, not only “additional” cases. Maternal and neonatal morbidity rates were within the confidence bounds for all three predicted scenarios.

Conclusions

Our study suggests that the widely adopted new diagnostic criteria for GDM are associated with increased obstetric intervention rates and lower macrosomia rates but with no clear impacts on maternal or neonatal morbidity.

Key messages

A diagnostic criteria change has identified more GDM pregnancies without clear benefit for outcomes.

The Comparative Effectiveness of Varenicline and Nicotine Patches for Smoking Abstinence During Pregnancy: Evidence From a Population-based Cohort Study

INTRODUCTION

In the general population, varenicline is consistently shown to be more efficacious for smoking cessation than nicotine replacement therapy (NRT). Current clinical guidelines for the management of smoking during pregnancy recommend against the use of varenicline, whilst supporting the use of NRT. However, little is known about the comparative effectiveness of these smoking cessation therapies among pregnant women.

AIMS AND METHODS

Routinely-collected records of all births in two Australian States during 2011 and 2012 were used to create a population-based cohort of women who smoked during the first half of pregnancy. Pharmaceutical dispensing data were used to identify varenicline and nicotine patch dispensings in the first half of pregnancy. Propensity score matching was used to account for the potentially different distribution of confounding factors between the treatment groups. The outcome was defined as smoking abstinence during the second half of pregnancy.

RESULTS

After propensity score-matching, our cohort comprised 60 women who used varenicline and 60 who used nicotine patches during the first half of pregnancy. More varenicline users (33.3%, 95% CI: 21.7%-46.7%) quit smoking than nicotine patch users (13.3%, 95% CI: 5.9%-24.6%). The adjusted rate difference was 24.2% (95% CI: 10.2%-38.2%) and the adjusted relative risk was 2.8 (95% CI: 1.4-5.7).

CONCLUSIONS

Varenicline was almost three times more effective than nicotine patches in assisting pregnant women to quit smoking. Further studies are needed to corroborate our results. Together with data on the safety of varenicline during pregnancy, evidence regarding the relative benefit of varenicline and NRT during pregnancy important for informing clinical decisions for pregnant smokers.

IMPLICATIONS

This study is the first to measure the comparative effectiveness of varenicline and nicotine patches during pregnancy - women using varenicline were almost three times as likely to quit smoking than those using nicotine patches. This study addressed a clinically important question using an observational study, noting that there is an absence of evidence from randomized controlled trials because of the ethical issues associated with including pregnant women in clinical trials of medicines of unknown safety.

Estimating pneumococcal vaccine coverage among Australian Indigenous children and children with medically at-risk conditions using record linkage

BACKGROUND

Risk-based recommendations are common for pneumococcal vaccines but little is known about their uptake. In Australia, pneumococcal conjugate vaccine (PCV) was funded only for Aboriginal or Torres Strait Islander (Indigenous) children and those with underlying medical conditions in 2001, and then there were different booster dose recommendations depending on risk after the introduction of universal PCV vaccination in 2005.

METHODS

We measured coverage of PCV dose 3 and additional PCV and 23-valent pneumococcal polysaccharide vaccine (PPV23) doses by risk group among children born in July 2001-December 2012 in two Australian states using linked immunisation and hospitalisation data (available until December 2013). We ascertained medical risk conditions using hospitalisation diagnosis codes and Indigenous status using an established algorithm, comparing coverage for children born pre (2001-2004) and post (2005-2012) universal PCV funding.

RESULTS

Among 1.3 million children, 63,897 (4.9%) were Indigenous and 32,934 (2.5%) had at least one medically at-risk condition identified by age 6 months. For births in 2001-2004, coverage for PCV dose 3 by 1 year of age was 37% for Indigenous, 15% for medically at-risk and 11% in other children, increasing to 83%, 91% and 92%, respectively for births in 2005-2012. In children with medically at-risk conditions, PCV dose 4 coverage by 2 years was 1% for 2001-2004 births, increasing to 9% for 2005-2012 births, with PPV23 coverage by 6 years 3% in both cohorts. Among eligible Indigenous children, PPV23 coverage by 3 years was 45% for 2001-2004 births and 51% for 2005-2012 births.

CONCLUSIONS

Coverage with additional recommended booster doses was very low among children with medical conditions, and only modest among Indigenous children. If additional PCV doses are recommended for some risk groups, especially in the context of routine schedules with reduced doses (e.g. 2 + 1 and 1 + 1), measures to improve implementation will be required.

Rates of neonatal morbidity by maternal region of birth and gestational age in New South Wales, Australia 2003-2016

INTRODUCTION

Research suggests that neonatal morbidity differs by maternal region of birth at different gestational ages. This study aimed to determine the overall and gestation-specific risk of neonatal morbidity by maternal region of birth, after adjustment for maternal, infant and birth characteristics, for women giving birth in New South Wales, Australia, from 2003 to 2016.

MATERIAL AND METHODS

The study utilized a retrospective cohort study design using linked births, hospital and deaths data. Modified Poisson regression was used to determine risk with 95% confidence intervals (95% CI) of neonatal morbidity by maternal region of birth, overall and at each gestational age, compared with Australian or New Zealand-born women giving birth at 39 weeks.

RESULTS

There were 1 074 930 live singleton births ≥32 weeks' gestation that met the study inclusion criteria, and 44 394 of these were classified as morbid, giving a neonatal morbidity rate of 4.13 per 100 live births. The gestational age-specific neonatal morbidity rate declined from 32 weeks' gestation, reaching a minimum at 39 weeks in all maternal regions of birth. The unadjusted neonatal morbidity rate was highest in South Asian-born women at most gestations. Adjusted rates of neonatal morbidity between 32 and 44 weeks were significantly lower for babies born to East (adjusted relative risk [aRR] 0.65, 95% CI 0.62-0.68), South-east (aRR 0.76, 95% CI 0.73-0.79) and West Asian-born (aRR 0.93, 95% CI 0.88-0.98) mothers, and higher for babies of Oceanian-born (aRR 1.11, 95% CI 1.04-1.18) mothers, compared with Australian or New Zealand-born mothers. Babies of African, Oceanian, South Asian and West Asian-born women had a lower adjusted risk of neonatal morbidity than Australian or New Zealand-born women until 37 or 38 weeks' gestation, and thereafter an equal or higher risk in the term and post-term periods.

CONCLUSIONS

Maternal region of birth is an independent risk factor for neonatal morbidity in New South Wales.

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.

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.

Use of smoking cessation pharmacotherapies during pregnancy is not associated with increased risk of adverse pregnancy outcomes: a population-based cohort study

BACKGROUND

Varenicline, bupropion and nicotine replacement therapy (NRT) are three effective pharmacotherapies for smoking cessation, but data about their safety in pregnancy are limited. We assessed the risk of adverse perinatal outcomes and major congenital anomalies associated with the use of these therapies in pregnancy in Australia.

METHODS

Perinatal data for 1,017,731 deliveries (2004 to 2012) in New South Wales and Western Australia were linked to pharmaceutical dispensing, hospital admission and death records. We identified 97,875 women who smoked during pregnancy; of those, 233, 330 and 1057 were exposed to bupropion, NRT and varenicline in pregnancy, respectively. Propensity scores were used to match exposed women to those who were unexposed to any smoking therapy (1:10 ratio). Propensity scores and gestational age at exposure were used to match varenicline-exposed to NRT-exposed women (1:1 ratio). Time-dependent Cox proportional hazards models estimated hazard ratios (HR) with 95% confidence intervals (95% CI) for any adverse perinatal event (a composite of 10 unfavourable maternal and neonatal outcomes) and any major congenital anomaly.

RESULTS

The risk of any adverse perinatal event was not significantly different between bupropion-exposed and unexposed women (39.2% versus 39.3%, HR 0.93, 95% CI 0.73-1.19) and between NRT-exposed and unexposed women (44.8% vs 46.3%, HR 1.02, 95% CI 0.84-1.23), but it was significantly lower in women exposed to varenicline (36.9% vs 40.1%, HR 0.86, 95% CI 0.77-0.97). Varenicline-exposed infants were less likely than unexposed infants to be born premature (6.5% vs 8.9%, HR 0.72, 95% CI 0.56-0.92), be small for gestational age (11.4% vs 15.4%, HR 0.68, 95% CI 0.56-0.83) and have severe neonatal complications (6.6% vs 8.2%, HR 0.74, 95% CI 0.57-0.96). Among infants exposed to varenicline in the first trimester, 2.9% had a major congenital anomaly (3.5% in unexposed infants, HR 0.91, 95% CI 0.72-1.15). Varenicline-exposed women were less likely than NRT-exposed women to have an adverse perinatal event (38.7% vs 51.4%, HR 0.58, 95% CI 0.33-1.05).

CONCLUSIONS

Pregnancy exposure to smoking cessation pharmacotherapies does not appear to be associated with an increased risk of adverse birth outcomes. Lower risk of adverse birth outcomes in varenicline-exposed pregnancies is inconsistent with recommendations that NRT be used in preference to varenicline.

Benefits of not smoking during pregnancy for Australian Aboriginal and Torres Strait Islander women and their babies: a retrospective cohort study using linked data

OBJECTIVES

To provide evidence for targeted smoking cessation policy, the aim of this study was to compare pregnancy outcomes of Aboriginal mothers who reported not smoking during pregnancy with Aboriginal mothers who reported smoking during pregnancy.

DESIGN

Population based retrospective cohort study using linked data.

SETTING

New South Wales, the most populous Australian state.

POPULATION

18 154 singleton babies born to 13 477 Aboriginal mothers between 2010 and 2014 were identified from routinely collected New South Wales datasets. Aboriginality was determined from birth records and from four linked datasets through an Enhanced Reporting of Aboriginality algorithm.

EXPOSURE

Not smoking at any time during pregnancy.

MAIN OUTCOME MEASURES

Unadjusted and adjusted relative risks (aRR) and 95% CIs from modified Poisson regression were used to examine associations between not smoking during pregnancy and maternal and perinatal outcomes including severe morbidity, inter-hospital transfer, perinatal death, preterm birth and small-for-gestational age. Population attributable fractions (PAFs) were calculated using adjusted relative risks.

RESULTS

Compared with babies born to mothers who smoked during pregnancy, babies born to non-smoking mothers had a lower risk of all adverse perinatal outcomes including perinatal death (aRR=0.58, 95% CI 0.44 to 0.76), preterm birth (aRR=0.58, 95% CI 0.53 to 0.64) and small-for-gestational age (aRR=0.35, 95% CI 0.32 to 0.39). PAFs (%) were 27% for perinatal death, 26% for preterm birth and 48% for small-for-gestational-age. Compared with women who smoked during pregnancy (n=8919), those who did not smoke (n=9235) had a lower risk of being transferred to another hospital (aRR=0.76, 95% CI 0.66 to 0.89).

CONCLUSIONS

Babies born to women who did not smoke during pregnancy had a lower risk of adverse perinatal outcomes. Rates of adverse outcomes among Aboriginal non-smokers were similar to those among the general population. These results quantify the proportion of adverse perinatal outcomes due to smoking and highlight why effective smoking cessation programme are urgently required for this population.

Assessing the effect of risk factors on rates of obstetric transfusion over time using two methodological approaches

Background

While red blood cell transfusion rates have declined in most Australian medical specialties, obstetric transfusion rates have instead been increasing. Obstetric transfusions are mostly linked to postpartum haemorrhage, the rates of which have also increased over time. This study used two methodological approaches to investigate recent trends in obstetric transfusion in New South Wales (NSW) and the extent to which this was influenced by changing maternal and pregnancy characteristics.

Methods

Linked birth and hospital records were used to examine rates of red blood cell transfusion in the postpartum period for mothers giving birth in NSW hospitals from 2005 to 2015. Logistic regression models were run to examine the contribution of maternal and pregnancy risk factors to changing rates of transfusion. Risk factors were divided into “pre-pregnancy” and “pregnancy related”. Crude and adjusted estimates of the effect of year of birth on obstetric transfusion rates were compared to assess the effect of risk factors on rates over time using two approaches. The first compared actual and predicted odds ratios of transfusion for each year. The second compared the observed increase in transfusion rate with that predicted after controlling for the risk factors.

Results

Among 935,659 births, the rate of obstetric transfusion rose from 13 per 1000 births in 2005 to 17 in 2011, and remained stable until 2015. From 2005 to 2015, postpartum haemorrhage increased from 74 to 114 per 1000 births. Compared with the rate in 2005, the available maternal and pregnancy characteristics only partially explained the change in rate of transfusion by 2015 (Method 1, crude odds ratio 1.39 (95% CI 1.25, 1.56); adjusted odds ratio 1.29 (95% CI 1.15, 1.45)). After adjustment for maternal and pregnancy characteristics, obstetric transfusion incidence was predicted to increase by 10.3%, but a 38.7% increase was observed (Method 2).

Conclusion

Rates of obstetric transfusion have stabilised after a period of increase. The trend could not be fully explained by measured maternal and pregnancy characteristics with either of the two approaches. Further investigation of rates and maternal and clinical risk factors will help to inform and improve obstetric blood product use.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0595-6) contains supplementary material, which is available to authorized users.

Varenicline is More Effective than Nicotine Replacement Therapy During Pregnancy: Findings from the Smoking MUMS (Maternal Use of Medications and Safety) Study

IntroductionStudies in the general population suggest that varenicline is more effective than nicotine replacement therapy (NRT) for smoking cessation. However, clinical guidelines recommend against the use of varenicline during pregnancy and suggest NRT be used when the expected benefits outweigh the potential risks. Objectives and ApproachWe evaluated whether varenicline was more effective than NRT for smoking cessation when used during pregnancy. Routinely-collected records of all births (01/01/2011-12/31/2012) in New South Wales and Western Australia were used to identify a cohort of women who smoked during the first 20 weeks of pregnancy. Pharmaceutical dispensing data were then linked to identify varenicline or NRT dispensing in the first 20 weeks of pregnancy. Smoking cessation was defined as women reported not smoking after the first 20 weeks of pregnancy. Inverse probability of treatment weighting with propensity scores were used to account for differences between the two treatment groups. ResultsOverall, 117 women used varenicline and 135 NRT in the first 20 weeks of pregnancy. In the unweighted sample, more women who used varenicline quit smoking after the first 20 weeks than women using NRT (28.2% vs. 11.1%, crude rate difference:17.1%, 95% confidence intervals[CI]:7.4-26.8%). In the weighted sample, quitting rate was 12.7% (95%CI:0.8-24.6%) higher in pregnant smokers who used varenicline (27.4% vs. 14.7%) when compared to those who used NRT. Conclusion/ImplicationsPregnant smokers using varenicline were more likely to quit smoking than those using NRT. This information will assist healthcare providers to make informed recommendations, but data regarding safety of varenicline in pregnancy are also urgently needed. Future studies with greater statistical power are required to confirm our results.

Compliance with telephone triage advice among adults aged 45 years and older: an Australian data linkage study

Background

Middle-aged and older patients are prominent users of telephone triage services for timely access to health information and appropriate referrals. Non-compliance with advice to seek appropriate care could potentially lead to poorer health outcomes among those patients. It is imperative to assess the extent to which middle-aged and older patients follow triage advice and how this varies according to their socio-demographic, lifestyle and health characteristics as well as features of the call.

Methods

Records of calls to the Australian healthdirect helpline (July 2008–December 2011) were linked to baseline questionnaire data from the 45 and Up Study (participants age ≥ 45 years), records of emergency department (ED) presentations, hospital admissions, and medical consultation claims. Outcomes of the call included compliance with the advice “Attend ED immediately”; “See a doctor (immediately, within 4 hours, or within 24 hours)”; “Self-care”; and self-referral to ED or hospital within 24 h when given a self-care or low-urgency care advice. Multivariable logistic regression was used to investigate associations between call outcomes and patient and call characteristics.

Results

This study included 8406 adults (age ≥ 45 years) who were subjects of 11,088 calls to the healthdirect helpline. Rates of compliance with the advices “Attend ED immediately”, “See a doctor” and “Self-care” were 68.6%, 64.6% and 77.5% respectively, while self-referral to ED within 24 h followed 7.0% of calls. Compliance with the advice “Attend ED immediately” was higher among patients who had three or more positive lifestyle behaviours, called after-hours, or stated that their original intention was to attend ED, while it was lower among those who lived in rural and remote areas or reported high or very high levels of psychological distress. Compliance with the advice “See a doctor” was higher in patients who were aged ≥65 years, worked full-time, or lived in socio-economically advantaged areas, when another person made the call on the patient’s behalf, and when the original intention was to seek care from an ED or a doctor. It was lower among patients in rural and remote areas and those taking five medications or more. Patients aged ≥65 years were less likely to comply with the advice “Self-care”. The rates of self-referral to ED within 24 h were greater in patients from disadvantaged areas, among calls made after-hours or by another person, and when the original intention was to attend ED. Patients who were given a self-care or low-urgency care advice, whose calls concerned bleeding, cardiac, gastrointestinal, head and facial injury symptoms, were more likely to self-refer to ED.

Conclusions

Compliance with telephone triage advice among middle-age and older patients varied substantially according to both patient- and call-related factors. Knowledge about the patients who are less likely to comply with telephone triage advice, and about characteristics of calls that may influence compliance, will assist in refining patient triage protocols and referral pathways, training staff and tailoring service design and delivery to achieve optimal patient compliance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-017-2458-y) contains supplementary material, which is available to authorized users.

Emergency Department Attendance after Telephone Triage: A Population-Based Data Linkage Study

OBJECTIVE

To investigate compliance with telephone helpline advice to attend an emergency department (ED) and the acuity of patients who presented to ED following a call.

DATA SOURCES/COLLECTION METHODS

In New South Wales (NSW), Australia, 2009-2012, all (1.04 million) calls to a telephone triage service, ED presentations, hospital admissions and death registrations, linked using probabilistic data linkage.

STUDY DESIGN

Population-based, observational cohort study measuring ED presentations within 24 hours of a call in patients (1) with dispositions to attend ED (compliance) and (2) low-urgency dispositions (self-referral), triage categories on ED presentation.

PRINCIPAL FINDINGS

A total of 66.5 percent of patients were compliant with dispositions to attend an ED. A total of 6.2 percent of patients with low-urgency dispositions self-referred to the ED within 24 hours. After age adjustment, healthdirect compliant patients were significantly less likely (7.8 percent) to receive the least urgent ED triage category compared to the general NSW ED population (16.9 percent).

CONCLUSIONS

This large population-based data linkage study provides precise estimates of ED attendance following calls to a telephone triage service and details the predictors of ED attendance. Patients who attend an ED compliant with a healthdirect helpline disposition are significantly less likely than the general ED population to receive the lowest urgency triage category on arrival.

Polyurethane-Based Aerogels for Use as Environmentally Acceptable Super Insulants in the Future Appliance Market

ICI Polyurethanes has talked extensively about the introduction of VACPAC* panels (polyurethane-based vacuum insulation panels) into the appliance market. Details have been presented at previous SPI and Utech meetings. In the meantime, extensive field tests have been carried out and, recently, several commercial models have been launched based on "VACPAC" panel technology.

Researchers all over the world are now working on a next generation super-insulation material called aerogels. Aerogels are lightweight, air-filled materials with a low thermal conductivity. The microporosity of these materials greatly reduces the air conductivity. Most of these materials are silica based and rather brittle in nature. Some work has been reported on organic polymeric aerogels.

We have now completed the laboratory development work of polyurethane- and polyisocyanurate-based organic aerogels. These materials offer a thermal conductivity of 7 mW/mK at a modest vacuum of 10 mbar. When no vacuum is applied, and the aerogel is completely filled with air, the thermal conductivity is 22 mW/Mk.

This paper describes the factors that have been optimized to develop an aerogel material which, in the long term, it is believed, will be a viable filler material in moderate vacuum technology. The project has been focused towards the appliance industry where energy requirements are becoming more and more stringent.

The Effect of Blowing Agent Solubility on the Long Term Dimensional Stability of Rigid Polyurethane Foams

More environmentally acceptable blowing agents, such as hydrochlorofluoro-carbons (HCFCs), hydrofluorocarbons (HFCs), hydrocarbons, and carbon dioxide have now replaced chlorofluorocarbon (CFC) blowing agents in many rigid polyurethane (PUR) and polyisocyanurate-modified polyurethane (PIR) foam applications. However, these new blowing agents were not simply "drop-in" replacements for CFCs. In most cases, the structural matrix of the foam had to be adapted in order to accommodate the new blowing agent. Concerns about the long term performance of these new technologies have led to extensive programs of research, not only to address thermal performance, but also to understand the effects of these blowing agent changes on mechanical properties. While a great deal of progress has been made, the polyurethane industry is still in need of a means to fully assess long term mechanical and dimensional stability performance.

One particular problem related to the long term dimensional stability of rigid polyurethane foams is the effect of blowing agent dissolution into the polymer matrix. Such dissolution may cause a softening of the matrix known as a "plasticization effect." In order to reduce the risk of mechanical failure, foam density may be increased, in order to strengthen the foam. However, this raises foam cost, and makes polyurethanes less competitive against other insulation materials. Clearly, the rigid polyurethane foam industry is in need of an accurate means of predicting lowest reasonable density which provides acceptable long term performance.

This paper describes the results of a new test designed to quantify the plasticization effect, which provides a fast and accurate means of assessing long term dimensional stability. The new methodology was successfully applied to a number of PUR and PIR foams, expanded with several blowing agents. The degree of blowing agent uptake into the matrix was quantified, and its effects on mechanical properties of the foam was established. In addition, a few correlations were drawn between the new test and real life long term performance data.

The results indicate that the methodology presented in this paper allows for effective prediction and quantification of possible plasticizing effects associated with any blowing agent in a PUR or PIR matrix.

Inequalities in Hospitalized Unintentional Injury Between Aboriginal and Non-Aboriginal Children in New South Wales, Australia

OBJECTIVES

To quantify inequalities in rates of unintentional injury-related hospitalizations between Australian Aboriginal and non-Aboriginal children.

METHODS

We used linked hospital and mortality data to construct a retrospective whole-of-population birth cohort including 1,124,717 children born in the state of New South Wales, Australia, between July 1, 2000 and December 31, 2012. We adjusted hazard ratios (HRs) of first injury hospitalization for geographic clustering and individual- and area-level factors.

RESULTS

Aboriginal children were 1.6 times more likely than were non-Aboriginal children to be hospitalized for an unintentional injury. The largest inequalities were for poisoning (HR = 2.7; 95% CI = 2.4, 3.0) and injuries stemming from exposure to fire, flames, heat, and hot substances (HR = 2.4; 95% CI = 2.1, 2.7). Adjustment reduced the inequality for all unintentional injury overall (HR = 1.4; 95% CI = 1.3, 1.4) and within leading injury mechanisms.

CONCLUSIONS

Australian Aboriginal children suffer a disproportionately high burden of unintentional injury.

Mortality risk of opioid substitution therapy with methadone versus buprenorphine: a retrospective cohort study

BACKGROUND

Opioid dependence increases risk of premature mortality. Opioid substitution therapy with methadone or buprenorphine reduces mortality risk, especially for drug-related overdose. Clinical guidelines recommend methadone as the first line of opioid substitution therapy. We aimed to test whether buprenorphine treatment has a lower mortality risk than does methadone treatment by comparing all-cause mortality and drug-related overdose mortality at treatment induction, after in-treatment medication switches, and following treatment cessation.

METHODS

We did a retrospective cohort study of all patients with opioid dependency (n=32,033) in New South Wales, Australia, who started a methadone or buprenorphine treatment episode from Aug 1, 2001, to Dec 31, 2010, including 190,232·6 person-years of follow-up. We compared crude mortality rates (CMRs) for all-cause and drug-related overdose mortality, and mortality rate ratios (MRRs) according to age, sex, period in or out of treatment, medication type, and in-treatment switching.

FINDINGS

Patients who initiated with buprenorphine had reduced all-cause and drug-related mortality during the first 4 weeks of treatment compared with those who initiated with methadone (adjusted all-cause MRR 2·17, 95% CI 1·29-3·67; adjusted drug-related MRR 4·88, 1·73-13·69). For the remaining time on treatment, drug-related mortality risk did not differ (adjusted MRR 1·18, 95% CI 0·89-1·56), but weak evidence suggested that all-cause mortality was lower for buprenorphine than methadone (1·66, 1·40-1·96). In the 4 weeks after treatment cessation, all-cause mortality did not differ, but drug-related mortality was lower for methadone (adjusted all-cause MRR 1·12, 0·79-1·59; adjusted drug-related MRR 0·50, 0·29-0·86). Patients who switched from buprenorphine to methadone during treatment had lower mortality in the first 4 weeks of methadone treatment than matched controls who received methadone only (CMR difference 7·1 per 1000 person-years, 95% CI 0·1-14·0); no mortality difference was noted for switches from buprenorphine to methadone or for switches to either medication beyond the first 4 weeks of treatment.

INTERPRETATION

In a setting with high risk of death in the first 4 weeks of opioid substitution therapy, buprenorphine seemed to reduce mortality in this period, but little difference between buprenorphine and methadone was noted thereafter or for in-treatment switching of medications. Cross-cohort corroboration of our findings and further assessment of the stepped treatment model is warranted.

FUNDING

Australian National Health & Medical Research Council.

What factors contribute to positive early childhood health and development in Australian Aboriginal children? Protocol for a population-based cohort study using linked administrative data (The Seeding Success Study)

INTRODUCTION

Australian Aboriginal children are more likely than non-Aboriginal children to have developmental vulnerability at school entry that tracks through to poorer literacy and numeracy outcomes and multiple social and health disadvantages in later life. Empirical evidence identifying the key drivers of positive early childhood development in Aboriginal children, and supportive features of local communities and early childhood service provision, are lacking.

METHODS AND ANALYSIS

The study population will be identified via linkage of Australian Early Development Census data to perinatal and birth registration data sets. It will include an almost complete population of children who started their first year of full-time school in New South Wales (NSW), Australia, in 2009 and 2012. Early childhood health and development trajectories for these children will be constructed via linkage to a range of administrative data sets relating to birth outcomes, congenital conditions, hospital admissions, emergency department presentations, receipt of ambulatory mental healthcare services, use of general practitioner services, contact with child protection and out-of-home care services, receipt of income assistance and fact of death. Using multilevel modelling techniques, we will quantify the contributions of individual-level and area-level factors to variation in early childhood development outcomes in Aboriginal and non-Aboriginal children. Additionally, we will evaluate the impact of two government programmes that aim to address early childhood disadvantage, the NSW Aboriginal Maternal and Infant Health Service and the Brighter Futures Program. These evaluations will use propensity score matching methods and multilevel modelling.

ETHICS AND DISSEMINATION

Ethical approval has been obtained for this study. Dissemination mechanisms include engagement of stakeholders (including representatives from Aboriginal community controlled organisations, policy agencies, service providers) through a reference group, and writing of summary reports for policy and community audiences in parallel with scientific papers.

Causes of death in a cohort treated for opioid dependence between 1985 and 2005

AIMS

To examine changes in causes of death in a cohort treated for opioid dependence, across time and age; quantify years of potential life lost (YPLL); and identify avoidable causes of death.

DESIGN

People in New South Wales (NSW) who registered for opioid substitution therapy (OST), 1985-2005, were linked to a register of all deaths in Australia.

SETTING

NSW, Australia.

MEASUREMENTS

Crude mortality rates (CMRs), age-sex-standardized mortality rates (ASSRs) and standardized mortality ratios (SMRs) across time, sex and age. Years of potential life lost (YPLL) were calculated with reference to Australian life tables and by calculating years lost before the age of 65 years.

FINDINGS

There were 43 789 people in the cohort, with 412 216 person-years of follow-up. The proportion of the cohort aged 40+ years increased from 1% in 1985 to 39% in 2005. Accidental opioid overdoses, suicides, transport accidents and violent deaths declined with age; deaths from cardiovascular disease, liver disease and cancer increased. Among men, 89% of deaths were potentially avoidable; among women, 86% of deaths were avoidable. There were an estimated 160 555 YPLL in the cohort, an average of 44 YPLL per decedent and an average of 29 YPLL before age 65 years.

CONCLUSIONS

Among a cohort of opioid-dependent people in New South Wales, 1985-2005, almost nine in 10 deaths in the cohort were avoidable. There is huge scope to improve mortality among opioid-dependent people.

Inequalities in ventilation tube insertion procedures between Aboriginal and non-Aboriginal children in New South Wales, Australia: a data linkage study

OBJECTIVES

Australian Aboriginal children experience earlier, more frequent and more severe otitis media, particularly in remote communities, than non-Aboriginal children. Insertion of ventilation tubes is the main surgical procedure for otitis media. Our aim was to quantify inequalities in ventilation tube insertion (VTI) procedures between Australian Aboriginal and non-Aboriginal children, and to explore the influence of birth characteristics, socioeconomic background and geographical remoteness on this inequality.

DESIGN

Retrospective cohort study using linked hospital and mortality data from July 2000 to December 2008.

SETTING AND PARTICIPANTS

A whole-of-population cohort of 653 550 children (16 831 Aboriginal and 636 719 non-Aboriginal) born in a New South Wales hospital between 1 July 2000 and 31 December 2007 was included in the analysis.

OUTCOME MEASURE

First VTI procedure.

RESULTS

VTI rates were lower in Aboriginal compared with non-Aboriginal children (incidence rate (IR), 4.3/1000 person-years; 95% CI 3.8 to 4.8 vs IR 5.8/1000 person-years; 95% CI 5.7 to 5.8). Overall, Aboriginal children were 28% less likely than non-Aboriginal children to have ventilation tubes inserted (age-adjusted and sex-adjusted rate ratios (RRs) 0.72; 95% CI 0.64 to 0.80). After adjusting additionally for geographical remoteness, Aboriginal children were 19% less likely to have ventilation tubes inserted (age-adjusted and sex-adjusted RR 0.81; 95% CI 0.73 to 0.91). After adjusting separately for private patient/health insurance status and area socioeconomic status, there was no significant difference (age-adjusted and sex-adjusted RR 0.96; 95% CI 0.86 to 1.08 and RR 0.93; 95% CI 0.83 to 1.04, respectively). In the fully adjusted model, there were no significant differences in VTI rates between Aboriginal and non-Aboriginal children (RR 1.06; 95% CI 0.94 to 1.19).

CONCLUSIONS

Despite a much higher prevalence of otitis media, Aboriginal children were less likely to receive VTI procedures than their non-Aboriginal counterparts; this inequality was largely explained by differences in socioeconomic status and geographical remoteness.

The Smoking MUMS (Maternal Use of Medications and Safety) Study: protocol for a population-based cohort study using linked administrative data

INTRODUCTION

Approximately 14% of Australian women smoke during pregnancy. Although the risk of adverse outcomes is reduced by smoking cessation, less than 35% of Australian women quit smoking spontaneously during pregnancy. Evidence for the efficacy of bupropion, varenicline or nicotine replacement therapy as smoking cessation aids in the non-pregnant population suggest that pharmacotherapy for smoking cessation is worth exploring in women of childbearing age. Currently, little is known about the utilisation, effectiveness and safety of pharmacotherapies for smoking cessation during pregnancy; neither the extent to which they are used prior to pregnancy nor whether their use has changed in response to related policy reforms. The Smoking MUMS (Maternal Use of Medications and Safety) Study will explore these issues using linked person-level data for a population-based cohort of Australian mothers.

METHODS AND ANALYSIS

The cohort will be assembled by linking administrative health records for all women who gave birth in New South Wales or Western Australia since 2003 and their children, including records relating to childbirth, use of pharmaceuticals, hospital admissions, emergency department presentations and deaths. These longitudinal linked data will be used to identify utilisation of smoking cessation pharmacotherapies during and between pregnancies and to explore the associated smoking cessation rates and maternal and child health outcomes. Subgroup and temporal analyses will identify potential differences between population groups including indigenous mothers and social security recipients and track changes associated with policy reforms that have made alternative smoking cessation pharmacotherapies available.

ETHICS AND DISSEMINATION

Ethical approval has been obtained for this study. To enhance the translation of the project's findings into policy and practice, policy and clinical stakeholders will be engaged through a reference group and a policy forum will be held. Outputs from the project will include scientific papers and summary reports designed for policy audiences.

The contributions of viral hepatitis and alcohol to liver-related deaths in opioid-dependent people

BACKGROUND

Mortality rates are elevated among heroin-dependent populations compared to the general population. Liver disease is emerging as an important contributor to mortality as the heroin-dependent population ages. Two major risk factors for liver disease are hepatitis C virus infection and chronic heavy alcohol use. Both of these are highly prevalent among heroin dependent people, but their relative contribution to liver-related mortality is poorly understood.

METHODS

Data recording all prescriptions of opioid substitution treatment in New South Wales, Australia, 1997-2005, were linked to the National Death Index. Crude and standardised mortality rates and standardised mortality ratios were calculated for liver-related and other major causes of death. Frequency counts were obtained for viral hepatitis and alcohol mentions in underlying liver deaths.

RESULTS

There were 208 underlying liver deaths for a CMR of 72.4 per 100,000 py (95% CI 62.9, 82.9), and liver deaths occurred at 9.8 times the general population rate (95% CI 8.5, 11.2). There were increases in liver-related mortality over time. Viral hepatitis was mentioned in three-quarters (n=156, 76%), and alcohol in 43% (n=90) of underlying liver deaths.

CONCLUSIONS

Liver-related deaths were shown to be increasing in this heroin-dependent population, and the majority of these deaths involved chronic viral hepatitis infection. Increased uptake of treatment for hepatitis C virus infection is crucial to reducing the burden of liver-related mortality in this population. Hepatitis B vaccination, and screening of OST patients for alcohol use disorders and delivery of brief interventions as clinically indicated may also be of benefit.

The increasing mortality burden of liver disease among opioid-dependent people: cohort study

AIMS

Hepatitis C (HCV) infection is highly prevalent among injection drug users (IDUs) and likely to cause significant mortality over time, but little research attention has focused upon the magnitude of this risk, particularly among ageing users. This study examined trends over time in mortality attributed to liver disease, and in particular contrasting this with other more commonly studied causes of death [acquired immune deficiency syndrome (AIDS), suicide and overdose] among an ageing cohort of heroin-dependent people in Australia.

DESIGN

Data linkage study of methadone treatment entrants with the National Deaths Index.

SETTING

 A cohort entering methadone treatment for heroin dependence in New South Wales, Australia, 1980-85.

PARTICIPANTS

  A total of 2489 people entering methadone treatment for heroin dependence and 54,847 person-years (PY) of follow-up.

MEASUREMENTS

  Linkage of data on all methadone entrants between 1980 and 1985 with data from the Australian National Deaths Index, linked using probabilistic record linkage software.

FINDINGS

There were 8.2 deaths per 1000 PY [95% confidence interval (CI) 7.5-9.0], with standardized mortality ratios (SMRs) of 4.6 (95% CI 4.2-5.0). Almost one in five (17%) of deaths were from underlying liver-related causes, most commonly viral hepatitis. The overall mortality rate for any liver cause was 1.4 deaths per 1000 PY (95% CI 1.1-1.7), 17 times higher than to the general population (95% CI 13.4-21.3), with relative elevations more marked for females (SMR 27.9; 95% CI 17.7-41.9) than males (SMR 14.5; 95% CI 10.8-19.0). Liver mortality increased over time, becoming the most common cause of death by the end of follow-up.

CONCLUSIONS

  Liver disease has become the most common cause of mortality among ageing opioid-dependent people in an ageing Australian cohort. There is an imperative to reduce the long-term risks of HCV and other risks to the liver, including alcohol consumption, which are typically not the major clinical focus for this group.

Mortality among clients of a state-wide opioid pharmacotherapy program over 20 years: risk factors and lives saved

BACKGROUND

The small size of previous studies of mortality in opioid dependent people has prevented an assessment of the extent to which elevated mortality risks are consistent across time, clinical and/or patient groups. The current study examines reductions in mortality related to treatment in an entire treatment population.

METHODS

Data from the New South Wales (NSW) Pharmaceutical Drugs of Addiction System, recording every "authority to dispense" methadone or buprenorphine as opioid replacement therapy, 1985-2006, was linked with data from the National Deaths Index, a record of all deaths in Australia. Crude mortality rates and standardized mortality ratios were calculated according to age, sex, calendar year, period in- or out-of-treatment, medication type, previous treatment exposure and cause of death.

RESULTS

Mortality among 42,676 people entering opioid pharmacotherapy was elevated compared to age and sex peers. Drug overdose and trauma were the major contributors. Mortality was higher out of treatment, particularly during the first weeks, and it was elevated during induction onto methadone but not buprenorphine. Mortality during these risky periods changed across time and treatment episodes. Overall, mortality was similarly reduced (compared to out-of-treatment) whether patients were receiving methadone or buprenorphine. It was estimated that the program produced a 29% reduction in mortality across the entire cohort.

CONCLUSIONS

Mortality among treatment-seeking opioid-dependent persons is dynamic across time, patient and treatment variables. The comparative reduction in mortality during buprenorphine induction may be offset by the increased risk of longer out-of-treatment time periods. Despite periods of elevated risk, this large-scale provision of pharmacotherapy is estimated to have resulted in significant reductions in mortality.

Opioid agonist pharmacotherapy in New South Wales from 1985 to 2006: patient characteristics and patterns and predictors of treatment retention

AIMS

The aims of this study were to: examine the number and characteristics of patients entering and re-entering opioid replacement treatment between 1985 and 2006, to examine select demographic and treatment correlates of leaving treatment between 1985 and 2000, and to compare retention rates in methadone and buprenorphine maintenance treatment from 2001 to 2006.

DESIGN

A retrospective cohort study using register data from the Pharmaceutical Drugs of Addiction System.

SETTING

Opioid substitution treatment in New South Wales (NSW), Australia.

PARTICIPANTS

A total of n = 42 690 individuals prescribed opioid replacement treatment between 1985 and 2006 in NSW.

MEASUREMENTS

Client characteristics over time, retention in days in first treatment episode, number of episodes of treatment and proportion switching medication.

FINDINGS

Overall, younger individuals were significantly more likely to leave their first treatment episode than older individuals. In 2001-06, after controlling for age, sex and first administration point, the hazard of leaving treatment was 1.9 times for those on buprenorphine relative to those on methadone. Retention in treatment varied somewhat across historical time, with those entering during 1995-2000 more likely to leave at an earlier stage than those who entered before that time.

CONCLUSIONS

Retention in treatment appears to fluctuate in inverse proportion to the availability of heroin. Individuals in contemporary treatment are older users with a lengthy treatment history. This study has provided population-level evidence to suggest that retention in methadone and buprenorphine differ in routine clinical practice. Future work might investigate ways in which patient adherence and retention may be improved.

Comparing retention in treatment and mortality in people after initial entry to methadone and buprenorphine treatment

AIM To compare retention in treatment and mortality among people entering methadone and buprenorphine treatment for opioid dependence.

DATA SOURCES

The Pharmaceutical Drugs of Abuse System (PHDAS) database records start- and end-dates of all episodes of methadone and buprenorphine treatment in New South Wales, and the National Death Index (NDI) records all reported deaths.

METHODS

Data linkage study. First entrants to treatment between June 2002 and June 2006 were identified from the PHDAS database. Retention in treatment was compared between methadone and buprenorphine. Names were linked to the NDI database, and 'good matches' were identified. Deaths were classified as occurring during induction, maintenance and either post-methadone or post-buprenorphine, depending on the latest episode of treatment prior to death. The numbers of inductions into treatment, of total person-years spent in each treatment, and person-years post-methadone or buprenorphine, were calculated. Risk of death in different periods, and different treatments, was analysed using Poisson regression.

RESULTS

A total of 5992 people entered their first episode of treatment-3349 (56%) on buprenorphine, 2643 on methadone. Median retention was significantly longer in methadone (271 days) than buprenorphine (40 days). During induction, the risk of death was lower for buprenorphine (relative risk = 0.114, 95% confidence interval = 0.002-0.938, P = 0.02, Fisher's exact test). Risk of death was lowest during treatment, significantly higher in the first 12 months after leaving both methadone and buprenorphine. Beyond 12 months after leaving treatment, risk of death was non-significantly higher than during treatment.

CONCLUSIONS

Buprenorphine was safer during induction. Despite shorter retention in treatment, buprenorphine maintenance was not associated with higher risk of death.

Annual or biennial mammography screening for women at a higher risk with a family history of breast cancer: prognostic indicators of screen-detected cancers in New South Wales, Australia

OBJECTIVE

This study examined whether offering annual mammography screening for women with the risk factor of a family history of breast cancer resulted in more favorable prognostic indicators of diagnosed cancers than the usual approach of biennial screening.

METHODS

The study involved women aged 50-69 years with a family history of breast cancer, defined as having > or = 1 first-degree relative diagnosed with breast cancer, who were diagnosed with a screen-detected invasive breast cancer between 1998 and 2004 in BreastScreen New South Wales (n = 590). The women were grouped according to whether they screened in an area offering annual screening to women with a family history, or were offered the standard biennial screening. The odds of having favorable tumor size, grade, and nodal status prognosis were compared between these screening groups using logistic regression. A comparison group of women without a family history, all offered biennial screening, was also evaluated based on the same area groupings to examine whether any differences were due to the area, rather than the screening interval policy.

RESULTS

Women with a family history who were offered annual screening at BreastScreen NSW were significantly more likely than those who were offered biennial screening to be diagnosed with a tumor < or = 20 mm in size (adjusted odds ratio (AOR) = 1.91, 95% CI: 1.21-3.02), and to have a node-negative tumor (AOR = 1.61, 95% CI: 1.03-2.50). There were also significantly higher odds of being diagnosed with tumors < or = 15 mm (p < 0.001) and < or = 10 mm in size (p = 0.011) in women offered annual screening. There was no significant difference in the odds of a Grade 1 tumor being detected (AOR = 1.26, 95% CI: 0.87-1.81), although the direction of the effect was consistent with that seen for size and nodal status. No significant differences were found in the comparison group of women without a family history.

CONCLUSIONS

Offering annual screening for women aged 50-69 years with a family history of breast cancer significantly increased the odds of being diagnosed with a smaller, node-negative tumors. Further investigation is required to assess whether the improved prognostic indicators translate into significantly better mortality outcomes for women with a family history offered annually screening.

Consumption of ‘extra’ foods by Australian children: types, quantities and contribution to energy and nutrient intakes

OBJECTIVE

To measure the types and quantities of energy-dense, nutrient-poor 'extra' foods consumed by Australian children and adolescents and their contribution to total energy and nutrient intakes.

DESIGN, SETTING AND SUBJECTS

We used data from 3007 children, aged 2-18 years, who participated in the nationally representative 1995 National Nutrition Survey. Intake was determined by 24-h recall and 'extra' foods were defined using principles outlined in the Australian Guide to Healthy Eating (AGHE) and by applying cut points for maximum amounts of fat and sugar within each food category.

RESULTS

All children (99.8%) consumed at least one 'extra' food and the most commonly consumed were margarine, sugar-sweetened soft drinks, cordials and sugar. 'Extra' foods contributed 41% of daily energy intake. Those foods contributing most to energy intake were fried potatoes (4.2%), sugar-sweetened soft drinks (3.3%), ice cream/ice confection (3.1%) and cordials (2.7%). Age and sex were important determinants of 'extra' food intake, with males and older children generally consuming more and different types of, 'extra' foods than females and younger children. 'Extra' foods contributed 19% protein, 47% total fat, 47% saturated fat, 54% sugar, and approximately 20-25% of selected micronutrients to the diet. Calcium and zinc intakes from core foods were below 70% of the recommended dietary intakes for adolescent girls.

CONCLUSIONS

'Extra' foods are over-consumed at two to four times the recommended limits and contribute excessively to the energy, fat and sugar intakes of Australian children, while providing relatively few micronutrients. This is of concern in terms of children's weight and nutrient status.