Grading disorder severity and averted burden by access to treatment within the GBD framework: a case study with anxiety disorders.

BACKGROUND: The Global Burden of Disease Study (GBD) estimates burden by cause with major relevance for resource allocators globally. Non-fatal burden estimates are influenced by disorder severity. However, for many disorders, global severity is sourced from a single high-income country survey. We aimed to estimate severity distributions that vary by Healthcare Access Quality Index (HAQI) using anxiety disorders as a case study and present the usefulness of this method in simulating averted and avoidable burden globally. METHODS: In this case study, we estimated treatment use among respondents with anxiety disorder in the 1997 Australian National Survey of Mental Health and Wellbeing (NSMHWB), the source used to estimate severity of anxiety disorders in GBD. Treatment effects were sourced from the Cochrane Database of Systematic Reviews and pooled via network meta-analysis. Severity distribution was established via a meta-regression of their disability weights, derived from 12-item short form survey scores. We simulated the shift in severity across scenarios without access to treatment and with full access to optimal treatment (cognitive behavioural therapy and antidepressants). We interpolated this shift linearly along the HAQI, extrapolated country-specific severity from HAQI scores, and calculated averted and avoidable burden. FINDINGS: The database review sourced 56 reviews, of which eight were eligible for inclusion. These eight reviews reported on 156 randomised controlled trials, with 194 treatment effects. Respondents to the 1997 NSMHWB consisted of 5936 women (55·8%) and 4705 (44·2%) men aged 18 years or older (mean age and ethnicity data not available). The survey-weighted treatment effect size was -0·28 (95% uncertainty interval -0·45 to -0·12). The pooled treatment effect for full coverage optimal treatment was -1·07 (-1·47 to -0·64). The sequela-weighted disability weight among people with anxiety disorder in the NSMHWB was 0·141 (0·042 to 0·275). The estimated disability weight was 0·188 (0·070 to 0·341) after removing the benefits of treatment and 0·056 (0·013 to 0·140) after providing all people with anxiety disorder access to optimal treatment. Globally, 12·5% (4·6 to 21·5) of anxiety disorder burden was averted because of available treatment. However, 71·1% (46·2 to 87·6) of global anxiety disorder burden could be averted if all people with anxiety disorders had access to optimal treatment. INTERPRETATION: Because it is based on guidance from a single survey done in one high-income country, the burden of anxiety disorders in low-income and middle-income countries is probably underestimated by GBD. Despite the availability of effective treatments, low use of these treatments means that most burden is still avoidable. Most of the burden could be averted if all people with anxiety disorders had access to optimal treatment, highlighting the importance of public promotion and referral pathways of treatment for anxiety disorders. Location-specific severity distributions in GBD would greatly increase precision in burden estimates and highlight avertable burden to clinicians, public health practitioners, and policy makers. FUNDING: Queensland Health and Bill & Melinda Gates Foundation.

Diagnostic accuracy of the Composite International Diagnostic Interview (CIDI 3.0) in an urban Indigenous Australian sample.

OBJECTIVE: The Composite International Diagnostic Interview 3.0 is a standardised diagnostic interview commonly used in population-based mental health surveys, but has not been used in community-residing Indigenous Australians. This paper seeks to determine whether the Composite International Diagnostic Interview 3.0 can produce valid diagnostic information when compared with a diagnostic interview in an urban Indigenous Australian sample. METHOD: This research was conducted over 10 weeks with adult Indigenous clients of two participating Aboriginal Medical Services in South-East Queensland. Using a cross-sectional, repeated-measures design, participants were administered the Composite International Diagnostic Interview 3.0 by an Indigenous interviewer and within 2 weeks attended a second appointment with an Indigenous clinical psychologist, who produced a diagnostic summary. The Composite International Diagnostic Interview 3.0 diagnoses were compared with the diagnostic summaries and clinical concordance between the two measures was calculated. RESULTS: The diagnostic accuracy of the Composite International Diagnostic Interview 3.0 differed by module. The Post-traumatic Stress Disorder and Major Depression modules had good utility in diagnosing post-traumatic stress disorder and major depressive episodes, respectively; however, the Mania module that provides diagnoses of bipolar disorder was found to be unsuitable for this population. Although there were no identified contraindications for the use of the Generalised Anxiety and Alcohol Use Disorder modules, further research on the diagnostic accuracy of these modules is warranted. CONCLUSIONS: The Composite International Diagnostic Interview 3.0 can accurately diagnose some common mental disorders in an Indigenous Australian population, but was found to be unsuitable for others. Given these findings, care should be taken when using the Composite International Diagnostic Interview 3.0 in epidemiological prevalence studies with Indigenous Australian populations.

The Burden of Proof studies: assessing the evidence of risk.

Exposure to risks throughout life results in a wide variety of outcomes. Objectively judging the relative impact of these risks on personal and population health is fundamental to individual survival and societal prosperity. Existing mechanisms to quantify and rank the magnitude of these myriad effects and the uncertainty in their estimation are largely subjective, leaving room for interpretation that can fuel academic controversy and add to confusion when communicating risk. We present a new suite of meta-analyses-termed the Burden of Proof studies-designed specifically to help evaluate these methodological issues objectively and quantitatively. Through this data-driven approach that complements existing systems, including GRADE and Cochrane Reviews, we aim to aggregate evidence across multiple studies and enable a quantitative comparison of risk-outcome pairs. We introduce the burden of proof risk function (BPRF), which estimates the level of risk closest to the null hypothesis that is consistent with available data. Here we illustrate the BPRF methodology for the evaluation of four exemplar risk-outcome pairs: smoking and lung cancer, systolic blood pressure and ischemic heart disease, vegetable consumption and ischemic heart disease, and unprocessed red meat consumption and ischemic heart disease. The strength of evidence for each relationship is assessed by computing and summarizing the BPRF, and then translating the summary to a simple star rating. The Burden of Proof methodology provides a consistent way to understand, evaluate and summarize evidence of risk across different risk-outcome pairs, and informs risk analysis conducted as part of the Global Burden of Diseases, Injuries, and Risk Factors Study.

The contribution of general medical conditions to the non-fatal burden of mental disorders: register-based cohort study in Denmark.

BACKGROUND: General medical conditions (GMCs) often co-occur with mental and substance use disorders (MSDs). AIMS: To explore the contribution of GMCs to the burden of disease in people with MSDs, and investigate how this varied by age. METHOD: A population-based cohort of 6 988 507 persons living in Denmark during 2000-2015 followed for up to 16 years. Danish health registers were used to identify people with MSDs and GMCs. For each MSD, years lived with disability and health loss proportion (HeLP) were estimated for comorbid MSDs and GMCs, using a multiplicative model for disability weights. RESULTS: Those with any MSD lost the equivalent of 43% of healthy life (HeLP = 0.43, 95% CI 0.40-0.44) after including information on GMCs, which was an increase from 25% before including GMCs (HeLP = 0.25, 95% CI 0.23-0.27). Schizophrenia was associated with the highest burden of disease (HeLP = 0.77, 95% CI 0.68-0.85). However, within each disorder, the relative contribution of MSDs and GMCs varied. For example, in those diagnosed with schizophrenia, MSDs and GMCs accounted for 86% and 14% of the total health loss; in contrast, in those with anxiety disorders, the same proportions were 59% and 41%. In general, HeLP increased with age, and was mainly associated with increasing rates of pulmonary, musculoskeletal and circulatory diseases. CONCLUSIONS: In those with mental disorders, the relative contribution of comorbid GMCs to the non-fatal burden of disease increases with age. GMCs contribute substantially to the non-fatal burden of disease in those with MSDs.

Register-based metrics of years lived with disability associated with mental and substance use disorders: a register-based cohort study in Denmark.

BACKGROUND: Mental disorders account for a substantial proportion of the years lived with disability (YLDs) globally. These estimates have generally been calculated top down based on summary statistics. The aim for this study was to calculate YLDs and a novel related measure, Health Loss Proportion (HeLP), for 18 mental and substance use disorders, based on person-level register data (bottom up). METHODS: A cohort of 6 989 627 Danish residents (5·9% had a diagnosis of a mental or substance use disorder registered in the Danish Psychiatric Central Research Register) was investigated. YLDs (the duration of disease multiplied by a disability weight) were calculated for the disorder of interest and for comorbid mental and substance use disorders. HeLPs were estimated as YLDs associated with an index disorder and comorbid mental and substance use disorders divided by person-years at risk in persons with the index disorder. All analyses were adjusted for mental and substance use comorbidity using a multiplicative model of disability weights. FINDINGS: Major depressive disorder was the most prevalent disorder, although schizophrenia was the leading cause of YLDs in both sexes combined (YLDs 273·3 [95 % CI 232·3-313·6] per 100 000 person-years). People diagnosed with schizophrenia lost the equivalent of 73% (63-83%) of healthy life per year due to mental and substance use disorders, the largest HeLP of all mental and substance use disorders. Comorbidity of mental and substance use disorders accounted for 69-83% of HeLPs in people with either cannabis use disorders, other drug use disorder and ADHD. By contrast, comorbidity explained 11-23% of the HeLPs in people with autism spectrum disorders, conduct disorder, and schizophrenia. INTERPRETATION: Substantial variation in disability was observed across age, sex, and disorders. The new HeLP metric provides novel details of the contribution of comorbidity to the disability associated with mental and substance use disorders. FUNDING: The Danish National Research Foundation, Queensland Government Department of Health, European Union's Horizon 2020, Lundbeck Foundation, Stanley Medical Research Institute. TRANSLATION: For the Danish translation of the abstract see Supplementary Materials section.

The hidden burden of eating disorders: an extension of estimates from the Global Burden of Disease Study 2019.

BACKGROUND: Anorexia nervosa and bulimia nervosa are the only eating disorders included in the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, yet binge-eating disorder and other specified feeding or eating disorder (OSFED) are more prevalent. This study sought to estimate the prevalence and burden of binge-eating disorder and OSFED globally and present a case for their inclusion in GBD. METHODS: We sourced studies from the GBD 2019 anorexia nervosa and bulimia nervosa epidemiological databases, two systematic reviews that included studies with epidemiological estimates of binge-eating disorder and OSFED, and experts in the field. Studies, published between Jan 1, 1998, and March 1, 2019, were included if they reported non-zero prevalence of two or more eating disorders (anorexia nervosa, bulimia nervosa, binge-eating disorder, or OSFED) and diagnosed cases according to DSM-IV or DSM-5. The proportions of total eating disorder cases that met diagnostic criteria for each individual eating disorder were estimated via network meta-regression and simulation using studies reporting eating disorder prevalence. The global cases unrepresented in GBD 2019 were estimated using the proportions from the simulation and the GBD 2019 eating disorder prevalence. Disability weights for binge-eating disorder and OSFED were then estimated along with disability-adjusted life-years (DALYs). Estimates are presented with 95% uncertainty intervals (UIs). FINDINGS: 54 studies, of which 36 were from high-income countries, were included in the analysis. The number of global eating disorder cases in 2019 that were unrepresented in GBD 2019 was 41·9 million (95% UI 27·9-59·0), and consisted of 17·3 million (11·3-24·9) people with binge-eating disorder and 24·6 million (14·7-39·7) people with OSFED (vs 13·6 million [10·2-17·5] people with eating disorders in GBD 2019). Together, binge-eating disorder and OSFED caused 3·7 million (95% UI 2·0-6·5) DALYs globally, bringing the total eating disorder DALYs to 6·6 million (3·8-10·6) in 2019. INTERPRETATION: Binge-eating disorder and OSFED accounted for the majority of eating disorder cases and DALYs globally. These findings warrant the inclusion of binge-eating disorder and OSFED in future iterations of GBD, which will bring the burden experienced by people living with these disorders to the attention of policy makers with the means to target this burden. FUNDING: Queensland Health, Australian National Health and Medical Research Council, and Bill & Melinda Gates Foundation.

Nature and prevalence of combinations of mental disorders and their association with excess mortality in a population-based cohort study.

The nature and prevalence of combinations of mental disorders and their associations with premature mortality have never been reported in a comprehensive way. We describe the most common combinations of mental disorders and estimate excess mortality associated with these combinations. We designed a population-based cohort study including all 7,505,576 persons living in Denmark at some point between January 1, 1995 and December 31, 2016. Information on mental disorders and mortality was obtained from national registers. A total of 546,090 individuals (10.5%) living in Denmark on January 1, 1995 were diagnosed with at least one mental disorder during the 22-year follow-up period. The overall crude rate of diagnosis of mental disorders was 9.28 (95% CI: 9.26-9.30) per 1,000 person-years. The rate of diagnosis of additional mental disorders was 70.01 (95% CI: 69.80-70.26) per 1,000 person-years for individuals with one disorder already diagnosed. At the end of follow-up, two out of five individuals with mental disorders were diagnosed with two or more disorder types. The most prevalent were neurotic/stress-related/somatoform disorders (ICD-10 F40-F48) and mood disorders (ICD-10 F30-F39), which - alone or in combination with other disorders - were present in 64.8% of individuals diagnosed with any mental disorder. Mortality rates were higher for people with mental disorders compared to those without mental disorders. The highest mortality rate ratio was 5.97 (95% CI: 5.52-6.45) for the combination of schizophrenia (ICD-10 F20-F29), neurotic/stress-related/somatoform disorders and substance use disorders (ICD-10 F10-F19). Any combination of mental disorders was associated with a shorter life expectancy compared to the general Danish population, with differences in remaining life expectancy ranging from 5.06 years (95% CI: 5.01-5.11) to 17.46 years (95% CI: 16.86-18.03). The largest excess mortality was observed for combinations that included substance use disorders. This study reports novel estimates related to the "force of comorbidity" and provides new insights into the contribution of substance use disorders to premature mortality in those with comorbid mental disorders.

Association of Specific Mental Disorders With Premature Mortality in the Danish Population Using Alternative Measurement Methods.

Importance: The association of mental disorders with premature mortality published in the Global Burden of Disease (GBD) studies has been underestimated because these analyses have recommended using only a small number of mental disorders as causes of death to estimate years of life lost (YLL). Alternative methods have been introduced, such as estimating life-years lost (LYL), to compare individuals with mental disorders with the general population. Objectives: To generate register-based YLL and LYL estimates and to use these measurement methods to assess the association of specific mental disorders with premature mortality. Design, Setting, and Participants: This population-based cohort study included all persons with and without mental disorders aged 0 to 94 years who were living in Denmark between January 1, 2000, and December 31, 2015. Data were analyzed from January to December 2019. Main Outcomes and Measures: Danish health registers were used to identify mental disorder diagnoses, dates of death, and causes of death. The YLLs were estimated for the set of mental health-associated causes of death, and all-cause and cause-specific LYLs were estimated for 18 specific mental disorders and 3 broad categories of mental disorders that were recommended for use in the GBD studies. The association between the number of comorbid mental disorders (divided into categories of persons with ≥1 type of disorder, ≥2 types of disorders, ≥3 types of disorders, and ≥4 types of disorders) and LYL estimates was also examined. Results: A total of 6 989 627 individuals (3 481 219 male persons [49.8%] and 3 508 408 female persons [50.2%]; mean [SD] age at study enrollment, 32.2 [24.4] years) were followed up for a total of 85 911 461 person-years. The YLL rates per 100 000 person-years were highest for alcohol use disorder (for male individuals, 568.7 [95% CI, 564.4-572.7]; for female individuals, 155.5 [95% CI, 153.5-157.9]) and suicide (for male individuals, 590.1 [95% CI, 583.8-596.5]; for female individuals, 202.3 [95% CI, 198.5-206.4]). Although only 3 of 18 mental and substance use disorders could be associated with YLL, all mental disorders were associated with shorter life expectancies when LYL was used for measurement. Male and female individuals diagnosed with any mental disorder had life expectancies that were shorter by 11.2 years (95% CI, 11.1-11.3 years) and 7.9 years (95% CI, 7.8-8.0 years), respectively, and remaining life expectancy decreased further among those with comorbid mental disorders. Drug use disorders were associated with the highest excess LYL estimates; however, common mental disorders, such as depressive and anxiety disorders, were also associated with substantial premature mortality. Conclusions and Relevance: Mental disorders were observed to be associated with reductions in life expectancy. This finding provides a foundation for future intervention programs designed to reduce the differential mortality gap associated with mental disorders. Register-based studies allow the calculation of precise individual-level YLLs and LYLs, and both measurement methods are informative for health care planning. Compared with YLL, the novel LYL measurement approach may more precisely capture the association of mental disorders with premature mortality and facilitates the exploration of comorbidity and specific causes of death in individuals with mental disorders.

A comprehensive analysis of mortality-related health metrics associated with mental disorders: a nationwide, register-based cohort study.

BACKGROUND: Systematic reviews have consistently shown that individuals with mental disorders have an increased risk of premature mortality. Traditionally, this evidence has been based on relative risks or crude estimates of reduced life expectancy. The aim of this study was to compile a comprehensive analysis of mortality-related health metrics associated with mental disorders, including sex-specific and age-specific mortality rate ratios (MRRs) and life-years lost (LYLs), a measure that takes into account age of onset of the disorder. METHODS: In this population-based cohort study, we included all people younger than 95 years of age who lived in Denmark at some point between Jan 1, 1995, and Dec 31, 2015. Information on mental disorders was obtained from the Danish Psychiatric Central Research Register and the date and cause of death was obtained from the Danish Register of Causes of Death. We classified mental disorders into ten groups and causes of death into 11 groups, which were further categorised into natural causes (deaths from diseases and medical conditions) and external causes (suicide, homicide, and accidents). For each specific mental disorder, we estimated MRRs using Poisson regression models, adjusting for sex, age, and calendar time, and excess LYLs (ie, difference in LYLs between people with a mental disorder and the general population) for all-cause mortality and for each specific cause of death. FINDINGS: 7 369 926 people were included in our analysis. We found that mortality rates were higher for people with a diagnosis of a mental disorder than for the general Danish population (28·70 deaths [95% CI 28·57-28·82] vs 12·95 deaths [12·93-12·98] per 1000 person-years). Additionally, all types of disorders were associated with higher mortality rates, with MRRs ranging from 1·92 (95% CI 1·91-1·94) for mood disorders to 3·91 (3·87-3·94) for substance use disorders. All types of mental disorders were associated with shorter life expectancies, with excess LYLs ranging from 5·42 years (95% CI 5·36-5·48) for organic disorders in females to 14·84 years (14·70-14·99) for substance use disorders in males. When we examined specific causes of death, we found that males with any type of mental disorder lost fewer years due to neoplasm-related deaths compared with the general population, although their cancer mortality rates were higher. INTERPRETATION: Mental disorders are associated with premature mortality. We provide a comprehensive analysis of mortality by different types of disorders, presenting both MRRs and premature mortality based on LYLs, displayed by age, sex, and cause of death. By providing accurate estimates of premature mortality, we reveal previously underappreciated features related to competing risks and specific causes of death. FUNDING: Danish National Research Foundation.

Global Epidemiology and Burden of Schizophrenia: Findings From the Global Burden of Disease Study 2016.

Introduction: The global burden of disease (GBD) studies have derived detailed and comparable epidemiological and burden of disease estimates for schizophrenia. We report GBD 2016 estimates of schizophrenia prevalence and burden of disease with disaggregation by age, sex, year, and for all countries. Method: We conducted a systematic review to identify studies reporting the prevalence, incidence, remission, and/or excess mortality associated with schizophrenia. Reported estimates which met our inclusion criteria were entered into a Bayesian meta-regression tool used in GBD 2016 to derive prevalence for 20 age groups, 7 super-regions, 21 regions, and 195 countries and territories. Burden of disease estimates were derived for acute and residual states of schizophrenia by multiplying the age-, sex-, year-, and location-specific prevalence by 2 disability weights representative of the disability experienced during these states. Findings: The systematic review found a total of 129 individual data sources. The global age-standardized point prevalence of schizophrenia in 2016 was estimated to be 0.28% (95% uncertainty interval [UI]: 0.24-0.31). No sex differences were observed in prevalence. Age-standardized point prevalence rates did not vary widely across countries or regions. Globally, prevalent cases rose from 13.1 (95% UI: 11.6-14.8) million in 1990 to 20.9 (95% UI: 18.5-23.4) million cases in 2016. Schizophrenia contributes 13.4 (95% UI: 9.9-16.7) million years of life lived with disability to burden of disease globally. Conclusion: Although schizophrenia is a low prevalence disorder, the burden of disease is substantial. Our modeling suggests that significant population growth and aging has led to a large and increasing disease burden attributable to schizophrenia, particularly for middle income countries.

The prevalence and burden of mental and substance use disorders in Australia: Findings from the Global Burden of Disease Study 2015.

OBJECTIVES: Timely and accurate assessments of disease burden are essential for developing effective national health policies. We used the Global Burden of Disease Study 2015 to examine burden due to mental and substance use disorders in Australia. METHODS: For each of the 20 mental and substance use disorders included in Global Burden of Disease Study 2015, systematic reviews of epidemiological data were conducted, and data modelled using a Bayesian meta-regression tool to produce prevalence estimates by age, sex, geography and year. Prevalence for each disorder was then combined with a disorder-specific disability weight to give years lived with disability, as a measure of non-fatal burden. Fatal burden was measured as years of life lost due to premature mortality which were calculated by combining the number of deaths due to a disorder with the life expectancy remaining at the time of death. Disability-adjusted life years were calculated by summing years lived with disability and years of life lost to give a measure of total burden. Uncertainty was calculated around all burden estimates. RESULTS: Mental and substance use disorders were the leading cause of non-fatal burden in Australia in 2015, explaining 24.3% of total years lived with disability, and were the second leading cause of total burden, accounting for 14.6% of total disability-adjusted life years. There was no significant change in the age-standardised disability-adjusted life year rates for mental and substance use disorders from 1990 to 2015. CONCLUSION: Global Burden of Disease Study 2015 found that mental and substance use disorders were leading contributors to disease burden in Australia. Despite several decades of national reform, the burden of mental and substance use disorders remained largely unchanged between 1990 and 2015. To reduce this burden, effective population-level preventions strategies are required in addition to effective interventions of sufficient duration and coverage.