A new data driven method for summarising multiple cause of death data.

BACKGROUND: National mortality statistics are based on a single underlying cause of death. This practice does not adequately represent the impact of the range of conditions experienced in an ageing population in which multimorbidity is common. METHODS: We propose a new method for weighting the percentages of deaths attributed to different causes that takes account of the patterns of associations among underlying and contributing causes of death. It is driven by the data and unlike previously proposed methods does not rely on arbitrary choices of weights which can over-emphasise the contribution of some causes of death. The method is illustrated using Australian mortality data for people aged 60 years or more. RESULTS: Compared to the usual method based only on the underlying cause of death the new method attributes higher percentages of deaths to conditions like diabetes and dementia that are frequently mentioned as contributing causes of death, rather than underlying causes, and lower percentages to conditions to which they are closely related such as ischaemic heart disease and cerebrovascular disease. For some causes, notably cancers, which are usually recorded as underlying causes with few if any contributing causes the new method produces similar percentages to the usual method. These different patterns among groups of related conditions are not apparent if arbitrary weights are used. CONCLUSION: The new method could be used by national statistical agencies to produce additional mortality tables to complement the current tables based only on underlying causes of death.

Accuracy of death certifications of diabetes, dementia and cancer in Australia: a population-based cohort study.

BACKGROUND: National mortality statistics are only based on the underlying cause of death, which may considerably underestimate the effects of some chronic conditions. METHODS: The sensitivity, specificity, and positive and negative predictive values for diabetes (a common precursor to multimorbidity), dementia (a potential accelerant of death) and cancer (expected to be well-recorded) were calculated from death certificates for 9 056 women from the 1921-26 cohort of the Australian Longitudinal Study on Women's Health. Log binomial regression models were fitted to examine factors associated with the sensitivity of death certificates with these conditions as underlying or contributing causes of death. RESULTS: Among women who had a record of each of these conditions in their lifetime, the sensitivity was 12.3% (95% confidence interval, 11.0%, 13.7%), 25.2% (23.7%, 26.7%) and 57.7% (55.9%, 59.5%) for diabetes, dementia and cancer, respectively, as the underlying cause of death, and 40.9% (38.8%, 42.9%), 52.3% (50.6%, 54.0%) and 67.1% (65.4%, 68.7%), respectively, if contributing causes of death were also taken into account. In all cases specificity (> 97%) and positive predictive value (> 91%) were high, and negative predictive value ranged from 69.6% to 84.6%. Sensitivity varied with age (in different directions for different conditions) but not consistently with the other sociodemographic factors. CONCLUSIONS: Death rates associated with common conditions that occur in multimorbidity clusters in the elderly are underestimated in national mortality statistics, but would be improved if the multiple causes of death listed on a death certificate were taken into account in the statistics.

What can death records tell us about multimorbidity?

BACKGROUND: Multimorbidity has been measured from many data sources which show that prevalence increases with age and is usually greater among women than men and in more recent periods. Analyses of multiple cause of death data have shown different patterns of multimorbidity associated with demographic and other characteristics. METHODS: Deaths in Australia among over 1.7 million decedents aged 55+ were stratified into three types: medically certified deaths, coroner-referred deaths with natural underlying causes and coroner-referred deaths with external underlying causes. Multimorbidity was measured by prevalence of ≥2 causes and analysed over three periods based on administrative changes: 2006-2012, 2013-2016 and 2017-2018. Poisson regression was used to examine the influence of gender, age and period. RESULTS: The prevalence of deaths with multimorbidity was 81.0% for medically certified deaths, 61.1% for coroner-referred deaths with natural underlying causes and 82.4% for coroner-referred deaths with external underlying causes. For medically certified deaths, multimorbidity increased with age: incidence rate ratio (IRR 1.070, 95% CI 1.068, 1.072) was lower for women than men (0.954, 95% CI 0.952, 0.956) and changed little over time. For coroner-referred deaths with natural underlying causes, multimorbidity showed the expected pattern increasing with age (1.066, 95% CI 1.062, 1.070) and being higher for women than men (1.025, 95% CI 1.015, 1.035) and in more recent periods. For coroner-referred deaths with external underlying causes, there were marked increases over time that differed by age group due to changes in coding processes. CONCLUSION: Death records can be used to examine multimorbidity in national populations but, like other data sources, how the data were collected and coded impacts the conclusions.

A Longitudinal Study Examining Changes in Street Connectivity, Land Use, and Density of Dwellings and Walking for Transport in Brisbane, Australia.

BACKGROUND: Societies face the challenge of keeping people active as they age. Walkable neighborhoods have been associated with physical activity, but more rigorous analytical approaches are needed. OBJECTIVES: We used longitudinal data from adult residents of Brisbane, Australia (40-65 years of age at baseline) to estimate effects of changes in neighborhood characteristics over a 6-y period on the likelihood of walking for transport. METHODS: Analyses included 2,789-9,747 How Areas Influence Health and Activity (HABITAT) cohort participants from 200 neighborhoods at baseline (2007) who completed up to three follow-up questionnaires (through 2013). Principal components analysis was used to derive a proxy measure of walkability preference. Environmental predictors were changes in street connectivity, residential density, and land use mix within a one-kilometer network buffer. Associations with any walking and minutes of walking were estimated using logistic and linear regression, including random effects models adjusted for time-varying confounders and a measure of walkability preference, and fixed effects models of changes in individuals to eliminate confounding by time-invariant characteristics. RESULTS: Any walking for transport (vs. none) was increased in association with an increase in street connectivity (+10 intersections, fixed effects OR=1.19; 95% confidence interval (CI): 1.07, 1.32), residential density (+5 dwellings/hectare, OR=1.10; 95% CI: 1.05, 1.15), and land-use mix (10% increase, OR=1.12; 95% CI: 1.00, 1.26). Associations with minutes of walking were positive based on random effects models, but null for fixed effects models. The association between land-use mix and any walking appeared to be limited to participants in the highest tertile of increased street connectivity (fixed effects OR=1.17; 95% CI: 0.99, 1.35 for a 1-unit increase in land-use mix; interaction p-value=0.05). CONCLUSIONS: Increases in street connectivity, residential density, and land-use heterogeneity were associated with walking for transport among middle-age residents of Brisbane, Australia. https://doi.org/10.1289/EHP2080.

A pilot study using the internet to study patterns of party drug use: processes, findings and limitations.

Since the 1990s there has been a rise in both the prevalence of party drug use in Australia and the use of party drug-related websites. This study investigates whether it is feasible to recruit and survey party drug users via the internet. It took place in Victoria, Australia. Participants were directed to a website where they completed a brief, structured internet-based survey. A total of 460 responses were received over 31 days, 393 of which fitted all inclusion criteria. The sample consisted predominately of young, male polydrug users and is one of the largest samples of party drug users in Australia reported thus far. It was concluded that it is feasible to recruit and survey current party drug users via the internet and that this method is quicker and cheaper than traditional survey methods, although samples are not necessarily representative of the party drug-using population. Other limitations and advantages are discussed.

Identifying patterns of item missing survey data using latent groups: an observational study.

OBJECTIVES: To examine whether respondents to a survey of health and physical activity and potential determinants could be grouped according to the questions they missed, known as 'item missing'. DESIGN: Observational study of longitudinal data. SETTING: Residents of Brisbane, Australia. PARTICIPANTS: 6901 people aged 40-65 years in 2007. MATERIALS AND METHODS: We used a latent class model with a mixture of multinomial distributions and chose the number of classes using the Bayesian information criterion. We used logistic regression to examine if participants' characteristics were associated with their modal latent class. We used logistic regression to examine whether the amount of item missing in a survey predicted wave missing in the following survey. RESULTS: Four per cent of participants missed almost one-fifth of the questions, and this group missed more questions in the middle of the survey. Eighty-three per cent of participants completed almost every question, but had a relatively high missing probability for a question on sleep time, a question which had an inconsistent presentation compared with the rest of the survey. Participants who completed almost every question were generally younger and more educated. Participants who completed more questions were less likely to miss the next longitudinal wave. CONCLUSIONS: Examining patterns in item missing data has improved our understanding of how missing data were generated and has informed future survey design to help reduce missing data.

Trends in quetiapine use and non-fatal quetiapine-related ambulance attendances.

INTRODUCTION AND AIMS: Concern about the non-medical use of quetiapine and related acute harms is growing. Case series cite quetiapine as a potential drug of misuse, while recent research questions its relative safety in comparison with other atypical antipsychotic preparations. This paper explores population-level patterns of quetiapine-related ambulance attendances over time, identifying associated risk factors and potential subpopulations at-risk of acute harms. DESIGN AND METHODS: A retrospective analysis of quetiapine-, olanzapine- and risperidone-related ambulance attendances in metropolitan Melbourne and prescription data in Victoria, Australia. Trends in ambulance attendance and prescription rates, attendance characteristics, and associated risk factors were explored from 2001 to 2010. RESULTS: Quetiapine was consistently associated with substantially higher rates of ambulance attendances relative to prescription availability than olanzapine or risperidone. Quetiapine prescribing rates increased at a significantly greater magnitude than olanzapine or risperidone, leading to substantial increases in quetiapine attendances by population. Quetiapine-related attendances were associated with concurrent heroin and opioid replacement therapy toxicity, history of heroin and alcohol misuse, mood disorders, low Glasgow Coma Scale and women. DISCUSSION AND CONCLUSIONS: Trends in quetiapine-related ambulance attendances indicate rising community-level harms and greater harm relative to other atypical antipsychotics, while prescription patterns suggest increasing quetiapine availability. The association of quetiapine-related attendances with concurrent heroin and opioid replacement therapy toxicity as well as previous heroin and alcohol misuse suggest illicit and poly-drug users are a subpopulation at greater risk of quetiapine-related harms, consistent with emerging evidence of the use, misuse and diversion of quetiapine.

Trends over time in characteristics of pharmaceutical drug-related ambulance attendances in Melbourne.

INTRODUCTION AND AIMS: There is growing concern regarding pharmaceutical drug-related harms. Evidence suggests increasing non-medical use of pharmaceutical drugs, along with associated morbidity and mortality. This paper explores trends of pharmaceutical-related ambulance attendances over the past decade in order to identify populations experiencing acute harm, and levels of harms in the community. DESIGN AND METHODS: A retrospective analysis of pharmaceutical drug-related ambulance attendances in metropolitan Melbourne, Australia, is presented, with rates of attendances over the period 2000 to 2009 and change over time examined. Characteristics of attendances are explored to understand the nature of presentation and demographic characteristics. RESULTS: Benzodiazepines represented the drug group with the highest rates of attendances over the 10 year period. Rates of attendances increased significantly for opioid analgesics, while significant decreases were noted for benzodiazepines, antidepressant and anticonvulsants. While women represented the majority of patients for each drug category presented over the period examined, there was an increase in the proportion of men attended in relation to opioid analgesics. Alcohol involvement in presentations has increased significantly for all drug groups. DISCUSSION AND CONCLUSIONS: Increasing pharmaceutical-related ambulance attendances for opioid analgesics reflect increasing use, with the increase in other analgesic-related attendances also concerning. The overrepresentation of female patients reflects a population experiencing drug-related harm not reflected in illicit drug research. The rise of alcohol involvement represents heightened risk of adverse events including death, and suggests an area for public education to prevent alcohol and drug-related harms.