Using multiple-cause-of-death data as a complement of underlying-cause-of-death data in examining mortality differences in psychiatric disorders between countries

Causes of death in individuals with lifetime major depression: a comprehensive machine learning analysis from a community-based autopsy center

BACKGROUND

Depression can be associated with increased mortality and morbidity, but no studies have investigated the specific causes of death based on autopsy reports. Autopsy studies can yield valuable and detailed information on pathological ailments or underreported conditions. This study aimed to compare autopsy-confirmed causes of death (CoD) between individuals diagnosed with major depressive disorder (MDD) and matched controls. We also analyzed subgroups within our MDD sample, including late-life depression and recurrent depression. We further investigated whether machine learning (ML) algorithms could distinguish MDD and each subgroup from controls based on their CoD.

METHODS

We conducted a comprehensive analysis of CoD in individuals who died from nontraumatic causes. The diagnosis of lifetime MDD was ascertained based on the DSM-5 criteria using information from a structured interview with a knowledgeable informant. Eleven established ML algorithms were used to differentiate MDD individuals from controls by simultaneously analyzing different disease category groups to account for multiple tests. The McNemar test was further used to compare paired nominal data.

RESULTS

The initial dataset included records of 1,102 individuals, among whom 232 (21.1%) had a lifetime diagnosis of MDD. Each MDD individual was strictly paired with a control non-psychiatric counterpart. In the MDD group, the most common CoD were circulatory (67.2%), respiratory (13.4%), digestive (6.0%), and cancer (5.6%). Despite employing a range of ML models, we could not find distinctive CoD patterns that could reliably distinguish individuals with MDD from individuals in the control group (average accuracy: 50.6%; accuracy range: 39-59%). These findings were consistent even when considering factors within the MDD group, such as late-life or recurrent MDD. When comparing groups with paired nominal tests, no differences were found for circulatory (p=0.450), respiratory (p=0.790), digestive (p=1.000), or cancer (p=0.855) CoD.

CONCLUSIONS

Our analysis revealed that autopsy-confirmed CoD exhibited remarkable similarity between individuals with depression and their matched controls, underscoring the existing heterogeneity in the literature. Future research should prioritize more severe manifestations of depression and larger sample sizes, particularly in the context of CoD related to cancer.

Quantifying cause-related mortality in Australia, incorporating multiple causes: observed patterns, trends and practical considerations

BACKGROUND

Mortality statistics using a single underlying cause of death (UC) are key health indicators. Rising multimorbidity and chronic disease mean that deaths increasingly involve multiple conditions. However, additional causes reported on death certificates are rarely integrated into mortality indicators, partly due to complexities in data and methods. This study aimed to assess trends and patterns in cause-related mortality in Australia, integrating multiple causes (MC) of death.

METHODS

Deaths (n = 1 773 399) in Australia (2006-17) were mapped to 136 ICD-10-based groups and MC indicators applied. Age-standardized cause-related rates (deaths/100 000) based on the UC (ASRUC) were compared with rates based on any mention of the cause (ASRAM) using rate ratios (RR = ASRAM/ASRUC) and to rates based on weighting multiple contributing causes (ASRW).

RESULTS

Deaths involved on average 3.4 causes in 2017; the percentage with >4 causes increased from 20.9 (2006) to 24.4 (2017). Ischaemic heart disease (ASRUC = 73.3, ASRAM = 135.8, ASRW = 63.5), dementia (ASRUC = 51.1, ASRAM = 98.1, ASRW = 52.1) and cerebrovascular diseases (ASRUC = 39.9, ASRAM = 76.7, ASRW = 33.5) ranked as leading causes by all methods. Causes with high RR included hypertension (ASRUC = 2.2, RR = 35.5), atrial fibrillation (ASRUC = 8.0, RR = 6.5) and diabetes (ASRUC = 18.5, RR = 3.5); the corresponding ASRW were 12.5, 12.6 and 24.0, respectively. Renal failure, atrial fibrillation and hypertension ranked among the 10 leading causes by ASRAM and ASRW but not by ASRUC. Practical considerations in working with MC data are discussed.

CONCLUSIONS

Despite the similarities in leading causes under the three methods, with integration of MC several preventable diseases emerged as leading causes. MC analyses offer a richer additional perspective for population health monitoring and policy development.

Changes in reporting for unintentional injury deaths, United States of America

Objective

To quantify how changes in reporting of specific causes of death and of selecting underlying cause from among multiple causes of death contribute to trends in mortality from unintentional injury in Americans aged 65 years or older.

Methods

We extracted age-standardized unintentional injury mortality data in the United States Centers for Disease Control and Prevention online databases from 1999 to 2016. We used an attribution method to calculate two indicators: the proportion of mortality with specific codes out of all mortality; and the proportion of mortality with underlying cause of death selected from multiple causes of death. We conducted a linear regression to examine the changes over time in these proportions and in reported and age-adjusted mortality.

Findings

From 1999 through 2016, the proportion of cause-specific unintentional injury mortality in this age group increased from 74% in 1999 (136.9 out of 185.0 per 100 000 population) to 85% in 2016 (143.0 out of 169.1 per 100 000 population) based on multiple causes of death codes. The proportions of mortality with underlying cause of death selected out of multiple causes of death rose in all specific causes of unintentional injury except motor vehicle crash. Age-standardized mortality attributed to reporting changes increased steadily between 1999 and 2016. The increases for overall unintentional injury, fall, motor vehicle crash, suffocation, poisoning and fire or hot object were 24.2, 13.5, 2.1, 2.3, 1.6 and 0.4 deaths per 100 000 persons, respectively.

Conclusion

Changes in data reporting affect trends in overall and specific unintentional injury mortality over time for older Americans.

Leading causes of death among decedents with mention of schizophrenia on the death certificates in the United States

BACKGROUND

Little is known about the changes in the ranking of leading cause of death (COD) among people died with schizophrenia across years in the United States (U.S.). This study aims to determine the ranking of leading COD among U.S. decedents with mention of schizophrenia by age from 2000 to 2015.

METHODS

The mortality multiple COD files maintained by the National Center for Health Statistics were used to identify decedents aged 15 years old and above with mention of schizophrenia anywhere on the death certificates to determine the number and proportion of deaths attributed to various underlying CODs.

RESULTS

Of 13,289, 13,655, 14,135, and 15,033 people who died in 2000-2003, 2004-2007, 2008-2011and 2012-2015 with mention of schizophrenia, similar to all decedents, heart disease and cancer was the first and the second leading COD throughout the study years. Schizophrenia ranked the third in most years except in 2004-2007. The first leading COD for decedents with mention of schizophrenia aged 15-24, 25-44, 45-64, 65-74, and 75+ years old in 2012-2015 was suicide, accidents, heart disease, heart disease, and Alzheimer's disease and related dementia, respectively. Nevertheless, it was accidents, accidents, cancer, cancer, and heart disease, respectively for all decedents.

CONCLUSION

The ranking of leading CODs among U.S. decedents with mention of schizophrenia changed across years and differed from all decedents by age, which suggest that different interventions should be designed accordingly.

Suicide deaths among patients with end-stage renal disease receiving dialysis: A population-based retrospective cohort study of 64,000 patients in Taiwan

BACKGROUND

Patients with end-stage renal disease (ESRD) who receive dialysis may experience increased distress and risk of suicide.

METHODS

This population-based retrospective cohort study linked Taiwan's national register of ESRD patients on dialysis and the cause-of-death mortality data file. A separate multiple-cause-of-death data file was used to investigate the detailed suicide methods used. Standardized mortality ratios (SMRs) were calculated for the overall patient group and by sex, age, year of initiating dialysis, method of suicide, and time since initiation of dialysis.

RESULTS

Among 63,854 ESRD patients on dialysis, 133 died by suicide in Taiwan in 2006-2012; the suicide rate was 76.3 per 100,000 patient-years. The SMR for suicide was 2.38 (95% confidence interval [CI] 1.99-2.82) in this patient group. Suicide risk was highest in the first year of dialysis (SMR = 3.15, 95% CI 2.39-4.08). The risk of suicide by cutting was nearly 20 times (SMR = 19.91, 95% CI 12.88-29.39) that of the general population. Detailed information on death certificates indicated that three quarters of patients who killed themselves by cutting cut vascular accesses used for hemodialysis.

LIMITATIONS

Information on risk factors such as socioeconomic position and mental disorders was unavailable.

CONCLUSION

In a country where the national health insurance program covers most expenses associated with dialysis treatment, the suicide risk in ESRD patients on dialysis still increased nearly 140%. Adequate support for ESRD patients initiating dialysis and the assessment of risk of cutting vascular access as a potential means of suicide could be important strategies for suicide prevention.

Accounting for multimorbidity can affect the estimation of the Burden of Disease: a comparison of approaches

Background

Various Burden of Disease (BoD) studies do not account for multimorbidity in their BoD estimates. Ignoring multimorbidity can lead to inaccuracies in BoD estimations, particularly in ageing populations that include large proportions of persons with two or more health conditions. The objective of this study is to improve BoD estimates for the Netherlands by accounting for multimorbidity. For this purpose, we analyzed different methods for 1) estimating the prevalence of multimorbidity and 2) deriving Disability Weights (DWs) for multimorbidity by using existing data on single health conditions.

Methods

We included 25 health conditions from the Dutch Burden of Disease study that have a high rate of prevalence and that make a large contribution to the total number of Years Lived with a Disability (YLD). First, we analyzed four methods for estimating the prevalence of multimorbid conditions (i.e. independent, independent age- and sex-specific, dependent, and dependent sex- and age-specific). Secondly, we analyzed three methods for calculating the Combined Disability Weights (CDWs) associated with multimorbid conditions (i.e. additive, multiplicative and maximum limit). A combination of these two approaches was used to recalculate the number of YLDs, which is a component of the Disability-Adjusted Life Years (DALY).

Results

This study shows that the YLD estimates for 25 health conditions calculated using the multiplicative method for Combined Disability Weights are 5 % lower, and 14 % lower when using the maximum limit method, than when calculated using the additive method. Adjusting for sex- and age-specific dependent co-occurrence of health conditions reduces the number of YLDs by 10 % for the multiplicative method and by 26 % for the maximum limit method. The adjustment is higher for health conditions with a higher prevalence in old age, like heart failure (up to 43 %) and coronary heart diseases (up to 33 %). Health conditions with a high prevalence in middle age, such as anxiety disorders, have a moderate adjustment (up to 13 %).

Conclusions

We conclude that BoD calculations that do not account for multimorbidity can result in an overestimation of the actual BoD. This may affect public health policy strategies that focus on single health conditions if the underlying cost-effectiveness analysis overestimates the intended effects. The methodology used in this study could be further refined to provide greater insight into co-occurrence and the possible consequences of multimorbid conditions in terms of disability for particular combinations of health conditions.

Trend in rates for deaths with mention of schizophrenia on death certificates of US residents, 1999-2010

BACKGROUND

Trends in mortality rates for schizophrenia using multiple causes of death (including contributory causes) coded on death certificates in the US resident population apparently have not been reported.

METHODS

Age-standardized rates for deaths per 100,000 in 1999-2010 at age 15+ years (and for 15-64 and 65+ years) with mention of schizophrenia were examined for the US resident population, including variation by age, gender, race (blacks/African Americans and whites) and region.

RESULTS

Deaths at age 15+ years coded with schizophrenia as underlying cause were only 12 % of all deaths with mention of schizophrenia, for which the rate declined from 1.58 in 1999 (3,407 deaths) to 1.32 in 2010 (3,422 deaths) (percentage change or PC = -16 %). Declines were larger in females than males, in whites than blacks, and occurred in the Northeast, Midwest and South but not the West. The rate increased for age 15-64 years (PC = +28 %) (mainly in males), however, while declining for age 65+ years (PC = -35 %). For deaths at age 15-64 years with schizophrenia coded as other than the underlying cause, the largest continuous increase was for endocrine-metabolic diseases (predominantly diabetes mellitus) as underlying cause, with smaller increases in males for cardiovascular diseases, external causes and neoplasms.

CONCLUSION

Trends in the US rate for deaths with mention of schizophrenia varied among the sociodemographic groups examined. The lack of decline for age 15-64 years requires further study especially with regard to mediators (e.g., obesity) of excess mortality in schizophrenia identified from cohort studies.

Trends in bipolar disorder or depression as a cause of death on death certificates of US residents, 1999-2009

BACKGROUND

Temporal trends in mortality from bipolar disorder (BD) or depression in the US population, based on multiple causes (MC) rather than underlying cause (UC) alone on death certificates, apparently have not been examined.

METHOD

The annual US age-standardized rate (ASR) for deaths per 100,000 US residents age 15+ years, and age-specific rates, for BD or depression using MC versus UC alone was examined for 1999-2009; percentage change (PC) from 1999 to 2009 was calculated.

RESULTS

The ASRs at age 15+ years were much higher using MC than UC alone. For BD using MC, the ASR increased from 1999 to 2009 (PC +69.2 %) with larger increases in age groups within 15-64 years (PCs about 200 %). For depression using MC, the ASR rose from 1999 to 2003 and then declined, but the decline was restricted to age 65+ years; the ASR at age 15-64 years increased from 1999 to 2009 (PC +55.5 %). For deaths at age 15-64 years with BD or depression as other than UC, the ASRs increased for external causes, cardiovascular diseases, external causes, and neoplasms as UC.

CONCLUSION

The large increases in mortality from BD using MC are consistent with reported increases in BD prevalence rates in the US population. The temporal increases in death rates related to mood disorders at age 15-64 years may provide further support for the need for interventions to address the mediators of excess mortality identified from cohort studies.

US regional differences in death rates from depression

BACKGROUND

Studies in a few countries (including the US) have reported that mortality rates in the population from psychiatric disorders are much higher when they are based on all causes of death ("multiple causes" or "mentions") coded on death certificates versus only the underlying cause. Studies appear to be lacking on geographic variation within the US in mortality rates from psychiatric disorders based on multiple causes of death.

METHOD

The present study examined the US age-standardized rate (ASR) for death with depression using multiple causes versus underlying cause alone in each of the Census Bureau's four regions and nine divisions. ASRs for schizophrenia were also examined for comparison.

RESULTS

For the entire US, the ratio of the ASR based on multiple causes to the ASR based on underlying cause was 20.9 for depression and 9.2 for schizophrenia; in analyses by region and division, these ratios showed limited variation. The most consistent finding for both depression and schizophrenia was that ASRs, whether based on multiple causes or only on underlying cause, were highest in the Midwest region (especially the East North Central division) and lowest in the South (and in each of its three divisions). For ASRs (using multiple causes of death) from depression, these regional differences were evident within each of several levels of urbanization. For deaths with depression coded as other than the underlying cause, ASRs for each of the three most common underlying causes (cardiovascular diseases, intentional injuries, and neoplasms) were highest in the Midwest and lowest in the South.

CONCLUSION

Studies are needed to determine if these regional differences in mortality from depression are due to regional differences in: certifier practices (i.e., in assigning causes of death among persons with psychiatric conditions); the prevalence (among persons with psychiatric disorders) of lifestyle-related factors (e.g., tobacco use and obesity) that mediate mortality risks; and/or in unmet need for psychiatric treatment and medical care for other chronic diseases in persons with psychiatric conditions. Similar studies are needed of regional variation within other countries.