People get ready! A new generation of Alzheimer's therapies may require new ways to deliver and pay for healthcare.

The development of disease-modifying therapies (DMTs) for Alzheimer's disease (AD) has progressed over the last decade, and the first-ever therapies with potential to slow the progression of disease are approved in the United States. AD DMTs could provide life-changing opportunities for people living with this disease, as well as for their caregivers. They could also ease some of the immense societal and economic burden of dementia. However, AD DMTs also come with major challenges due to the large unmet medical need, high prevalence of AD, new costs related to diagnosis, treatment and monitoring, and uncertainty in the therapies' actual clinical value. This perspective article discusses, from the broad perspective of various health systems and stakeholders, how we can overcome these challenges and improve society's readiness for AD DMTs. We propose that innovative payment models such as performance-based payments, in combination with learning healthcare systems, could be the way forward to enable timely patient access to treatments, improve accuracy of cost-effectiveness evaluations and overcome budgetary barriers. Other important considerations include the need for identification of key drivers of patient value, the relevance of different economic perspectives (i.e. healthcare vs. societal) and ethical questions in terms of treatment eligibility criteria.

Predicting sojourn times across dementia disease stages, institutionalization, and mortality.

INTRODUCTION: Inferring the timeline from mild cognitive impairment (MCI) to severe dementia is pivotal for patients, clinicians, and researchers. Literature is sparse and often contains few patients. We aim to determine the time spent in MCI, mild-, moderate-, severe dementia, and institutionalization until death. METHODS: Multistate modeling with Cox regression was used to obtain the sojourn time. Covariates were age at baseline, sex, amyloid status, and Alzheimer's disease (AD) or other dementia diagnosis. The sample included a register (SveDem) and memory clinics (Amsterdam Dementia Cohort and Memento). RESULTS: Using 80,543 patients, the sojourn time from clinically identified MCI to death across all patient groups ranged from 6.20 (95% confidence interval [CI]: 5.57-6.98) to 10.08 (8.94-12.18) years. DISCUSSION: Generally, sojourn time was inversely associated with older age at baseline, males, and AD diagnosis. The results provide key estimates for researchers and clinicians to estimate prognosis.

The 2022 symposium on dementia and brain aging in low- and middle-income countries: Highlights on research, diagnosis, care, and impact.

Two of every three persons living with dementia reside in low- and middle-income countries (LMICs). The projected increase in global dementia rates is expected to affect LMICs disproportionately. However, the majority of global dementia care costs occur in high-income countries (HICs), with dementia research predominantly focusing on HICs. This imbalance necessitates LMIC-focused research to ensure that characterization of dementia accurately reflects the involvement and specificities of diverse populations. Development of effective preventive, diagnostic, and therapeutic approaches for dementia in LMICs requires targeted, personalized, and harmonized efforts. Our article represents timely discussions at the 2022 Symposium on Dementia and Brain Aging in LMICs that identified the foremost opportunities to advance dementia research, differential diagnosis, use of neuropsychometric tools, awareness, and treatment options. We highlight key topics discussed at the meeting and provide future recommendations to foster a more equitable landscape for dementia prevention, diagnosis, care, policy, and management in LMICs. HIGHLIGHTS: Two-thirds of persons with dementia live in LMICs, yet research and costs are skewed toward HICs. LMICs expect dementia prevalence to more than double, accompanied by socioeconomic disparities. The 2022 Symposium on Dementia in LMICs addressed advances in research, diagnosis, prevention, and policy. The Nairobi Declaration urges global action to enhance dementia outcomes in LMICs.

Structural equation modeling for identifying the drivers of health-related quality of life improvement experienced by patients with migraine receiving eptinezumab.

BACKGROUND: As new migraine therapies emerge, it is crucial for measures to capture the complexities of health-related quality of life (HRQoL) improvement beyond improvements in monthly migraine day (MMD) reduction. Investigations into the correlations between MMD reduction, symptom management, and HRQoL are lacking, particularly those that focus on improvements in canonical symptoms and improvement in patient-identified most-bothersome symptoms (PI-MBS), in patients treated with eptinezumab. This exploratory analysis identified efficacy measures mediating the effect of eptinezumab on HRQoL improvements in patients with migraine. METHODS: Data from the DELIVER study of patients with 2-4 prior preventive migraine treatment failures (NCT04418765) were inputted to two structural equation models describing sources of HRQoL improvement via Migraine-Specific Quality-of-Life Questionnaire (MSQ) scores. A single latent variable was defined to represent HRQoL and describe the sources of HRQoL in DELIVER. One model included all migraine symptoms while the second model included the PI-MBS as the only migraine symptom. Mediating variables capturing different aspects of efficacy included MMDs, other canonical symptoms, and PI-MBS. RESULTS: In the first model, reductions in MMDs and other canonical symptoms accounted for 35% (standardized effect size [SES] - 0.11) and 25% (SES - 0.08) of HRQoL improvement, respectively, with 41% (SES - 0.13) of improvement comprising "direct treatment effect," i.e., unexplained by mediators. In the second model, substantial HRQoL improvement with eptinezumab (86%; SES - 0.26) is due to MMD reduction (17%; SES - 0.05) and change in PI-MBS (69%; SES - 0.21). CONCLUSIONS: Improvements in HRQoL experienced by patients treated with eptinezumab can be substantially explained by its effect on migraine frequency and PI-MBS. Therefore, in addition to MMD reduction, healthcare providers should discuss PI-MBS improvements, since this may impact HRQoL. Health technology policymakers should consider implications of these findings in economic evaluation, as they point to alternative measurement of quality-adjusted life years to capture fully treatment benefits in cost-utility analyses. TRIAL REGISTRATION: ClinicalTrials.gov (Identifier: NCT04418765 ; EudraCT (Identifier: 2019-004497-25; URL: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2019-004497-25 ).

The value of maintaining cognition in patients with mild cognitive impairment: The innovation headroom and potential cost-effectiveness of roflumilast.

INTRODUCTION: Early health-technology assessment can support discussing scarce resource allocation among stakeholders. We explored the value of maintaining cognition in patients with mild cognitive impairment (MCI) by estimating: (1) the innovation headroom and (2) the potential cost effectiveness of roflumilast treatment in this population. METHODS: The innovation headroom was operationalized by a fictive 100% efficacious treatment effect, and the roflumilast effect on memory word learning test was assumed to be associated with 7% relative risk reduction of dementia onset. Both were compared to Dutch setting usual care using the adapted International Pharmaco-Economic Collaboration on Alzheimer's Disease (IPECAD) open-source model. RESULTS: The total innovation headroom expressed as net health benefit was 4.2 (95% bootstrap interval: 2.9-5.7) quality-adjusted life years (QALYs). The potential cost effectiveness of roflumilast was k€34 per QALY. DISCUSSION: The innovation headroom in MCI is substantial. Although the potential cost effectiveness of roflumilast treatment is uncertain, further research on its effect on dementia onset is likely valuable.

A glycan epitope correlates with tau in serum and predicts progression to Alzheimer's disease in combination with APOE4 allele status.

INTRODUCTION: There is an urgent need for novel blood biomarkers for the detection of Alzheimer's disease (AD). We previously showed that levels of the bisecting N-acetylglucosamine glycan epitope was elevated in cerebrospinal fluid in AD. However, its diagnostic value in blood is unknown. METHODS: We analyzed blood levels of bisecting N-acetylglucosamine and total tau in a retrospective cohort of 233 individuals. Progression to AD was compared between the groups using Cox regression. The predictive value of the biomarkers was determined by logistic regression. RESULTS: Bisecting N-acetylglucosamine correlated with tau levels (p < 0.0001). Individuals with an intermediate tau/bisecting N-acetylglucosamine ratio had elevated AD risk (hazard ratio = 2.06, 95% confidence interval [CI]: 1.18-3.6). Moreover, a combined model including tau/bisecting N-acetylglucosamine ratio, apolipoprotein E (APOE) ε4 status, and Mini-Mental State Examination score predicted future AD (area under the curve = 0.81, 95% CI: 0.68-0.93). DISCUSSION: Bisecting N-acetylglucosamine in combination with tau is a valuable blood biomarker for predicting AD.

The worldwide costs of dementia in 2019.

INTRODUCTION: Dementia is a leading cause of death and disability globally. Estimating total societal costs demonstrates the wide impact of dementia and its main direct and indirect economic components. METHODS: We constructed a global cost model for dementia, presenting costs as cumulated global and regional costs. RESULTS: In 2019, the annual global societal costs of dementia were estimated at US $1313.4 billion for 55.2 million people with dementia, corresponding to US $23,796 per person with dementia. Of the total, US $213.2 billion (16%) were direct medical costs, US $448.7 billion (34%) direct social sector costs (including long-term care), and US $651.4 billion (50%) costs of informal care. DISCUSSION: The huge costs of dementia worldwide place enormous strains on care systems and families alike. Although most people with dementia live in low- and middle-income countries, highest total and per-person costs are seen in high-income countries. HIGHLIGHTS: Global economic costs of dementia were estimated to reach US $1313.4 in 2019. Sixty-one percent of people with dementia live in low-and middle-income countries, whereas 74% of the costs occur in high-income countries. The impact of informal care accounts for about 50% of the global costs. The development of a long-term care infrastructure is a great challenge for low-and middle-income countries. There is a great need for more cost studies, particularly in low- and middle-income countries. Discussions of a framework for global cost comparisons are needed.

Cost-effectiveness models for Alzheimer's disease and related dementias: IPECAD modeling workshop cross-comparison challenge.

INTRODUCTION: The credibility of model-based economic evaluations of Alzheimer's disease (AD) interventions is central to appropriate decision-making in a policy context. We report on the International PharmacoEconomic Collaboration on Alzheimer's Disease (IPECAD) Modeling Workshop Challenge. METHODS: Two common benchmark scenarios, for the hypothetical treatment of AD mild cognitive impairment (MCI) and mild dementia, were developed jointly by 29 participants. Model outcomes were summarized, and cross-comparisons were discussed during a structured workshop. RESULTS: A broad concordance was established among participants. Mean 10-year restricted survival and time in MCI in the control group ranged across 10 MCI models from 6.7 to 9.5 years and 3.4 to 5.6 years, respectively; and across 4 mild dementia models from 5.4 to 7.9 years (survival) and 1.5 to 4.2 years (mild dementia). DISCUSSION: The model comparison increased our understanding of methods, data used, and disease progression. We established a collaboration framework to assess cost-effectiveness outcomes, an important step toward transparent and credible AD models.

Sensitivity to Change and Patient-Centricity of the Unified Multiple System Atrophy Rating Scale Items: A Data-Driven Analysis.

BACKGROUND: The Unified Multiple System Atrophy Rating Scale (UMSARS) is a commonly used semiquantitative rating scale to assess symptoms and measure disease progression in multiple system atrophy (MSA). However, it is currently incompletely understood which UMSARS items are the most sensitive to change and most relevant to the patient. OBJECTIVE: The objective of this study was to assess sensitivity to change and patient-centricity of single UMSARS items. METHODS: Data were taken from the European Multiple System Atrophy Study Group Natural History Study and the Rasagiline for Multiple System Atrophy trial. Sensitivity of change of an item of the UMSARS was assessed by calculation of a sensitivity-to-change ratio using its mean slope of progression divided by the standard deviation of the slope when modeling its progression over time. Patient-centricity was assessed through correlation of UMSARS items with quality-of-life measures. RESULTS: Progression rates above the mean in at least one of the two studies examined here were seen for seven items of UMSARS I and 11 items of UMSARS II. These items related to key motor functions such as swallowing, speech, handwriting, cutting food, hygiene, and dressing or walking, whereas items related to autonomic dysfunction were generally less sensitive to change in either data set. More UMSARS I items were identified as patient-centric compared with UMSARS II items, and items most strongly impacting patients' quality of life were those affecting verbal communication skills, personal hygiene, and walking. CONCLUSION: The present results illustrate the potential to optimize the UMSARS to enhance sensitivity to change and patient centricity. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Dementia prevention: The potential long-term cost-effectiveness of the FINGER prevention program.

INTRODUCTION: The aim of this study was to estimate the potential cost-effectiveness of the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER) program. METHODS: A life-time Markov model with societal perspective, simulating a cohort of people at risk of dementia reflecting usual care and the FINGER program. RESULTS: Costs were 1,653,275 and 1,635,346 SEK and quality-adjusted life years (QALYs) were 8.636 and 8.679 for usual care and the FINGER program, respectively, resulting in savings of 16,928 SEK (2023 US$) and 0.043 QALY gains per person, supporting extended dominance for the FINGER program. A total of 1623 dementia cases were avoided with 0.17 fewer person-years living with dementia. The sensitivity analysis confirmed the conclusions in most scenarios. DISCUSSION: The model provides support that programs like FINGER have the potential to be cost-effective in preventing dementia. Results at the individual level are rather modest, but the societal benefits can be substantial because of the large potential target population.

Predicting time to relapse in patients with schizophrenia according to patients' relapse history: a historical cohort study using real-world data in Sweden.

BACKGROUND: For patients with schizophrenia, relapse is a recurring feature of disease progression, often resulting in substantial negative impacts for the individual. Although a patient's relapse history (specifically the number of prior relapses) has been identified as a strong risk factor for future relapse, this relationship has not yet been meticulously quantified. The objective of this study was to use real-world data from Sweden to quantify the relationship of time to relapse in schizophrenia with a patient's history of prior relapses. METHODS: Data from the Swedish National Patient Register and Swedish Prescribed Drug Register were used to study relapse in patients with schizophrenia with a first diagnosis recorded from 2006-2015, using proxy definitions of relapse. The primary proxy defined relapse as a psychiatric hospitalisation of ≥7 days' duration. Hazard ratios (HRs) were calculated for risk of each subsequent relapse, and Aalen-Johansen estimators were used to estimate time to next relapse. RESULTS: 2,994 patients were included, and 5,820 relapse episodes were identified using the primary proxy. As the number of previous relapses increased, there was a general trend of decreasing estimated time between relapses. Within 1.52 years of follow-up, 50% of patients with no history of relapse were estimated to have suffered their first relapse episode. 50% of patients with one prior relapse were estimated to have a second relapse within 1.23 years (HR: 1.84 [1.71-1.99]) and time to next relapse further decreased to 0.89 years (HR: 2.77 [2.53-3.03]) and 0.22 years (HR: 18.65 [15.42-22.56]) for 50% of patients with two or ten prior relapses, respectively. Supplementary analyses using different inclusion/exclusion criteria for the study population and redefined proxies of relapse reflected the pattern observed with the primary analyses of a higher number of prior relapses linked with increased risk of/reduced estimated time to the next relapse. CONCLUSIONS: The results suggested a trend of accelerating disease progression in schizophrenia, each relapse episode predisposing an individual to the next within a shorter time period. These results emphasise the importance of providing early, effective, and tolerable treatments that better meet a patient's individual needs.

Controlling for selective dropout in longitudinal dementia data: Application to the SveDem registry.

INTRODUCTION: Loss to follow-up in dementia studies is common and related to cognition, which worsens over time. We aimed to (1) describe dropout and missing cognitive data in the Swedish dementia registry, SveDem; (2) identify factors associated with dropout; and (3) estimate propensity scores and use them to adjust for dropout. METHODS: Longitudinal cognitive data were obtained from 53,880 persons from the SveDem national quality dementia registry. Inverse probability of censoring weights (IPCWs) were estimated using a logistic regression model on dropout. RESULTS: The mean annualized rate of change in Mini-Mental State Examination (MMSE) in those with a low MMSE (0 to 10) was likely underestimated in the complete case analysis (+1.5 points/year) versus the IPCW analysis (-0.3 points/year). DISCUSSION: Handling dropout by IPCWs resulted in plausible estimates of cognitive decline. This method is likely of value to adjust for biased dropout in longitudinal cohorts of dementia.

The effect of self-assessed fatigue and subjective cognitive impairment on work capacity: The case of multiple sclerosis.

OBJECTIVES: The impact of physical disability in multiple sclerosis on employment is well documented but the effect of neurological symptoms has been less well studied. We investigated the independent effect of self-reported fatigue and cognitive difficulties on work. METHODS: In a large European cost of illness survey, self-reported fatigue, subjective cognitive impairment (SCI), and productivity at work were assessed with visual analogue scales (VAS 0-10). The analysis controlled for country, age, age at diagnosis, gender, education, and physical disability. RESULTS: A total of 13,796 patients were of working age and 6,598 were working. Physical disability had a powerful impact on the probability of working, as did education. The probability of working was reduced by 8.7% and 4.4% for each point increase on the VAS for SCI and fatigue, respectively ( p < 0.0001). Regular work hours decreased linearly with increasing severity of fatigue and cognitive problems, while sick leave during the 3 months preceding the assessment increased. Finally, the severity of both symptoms was associated with the level at which productivity at work was affected ( p < 0.0001). CONCLUSION: Our results confirm the independent contribution of self-reported fatigue and SCI on work capacity and highlight the importance of assessment in clinical practice.

Health-related quality of life experiences in children and adolescents born with esophageal atresia: A Swedish-German focus group study.

BACKGROUND: Esophageal atresia (EA) is a rare malformation of the esophagus, which needs surgical treatment. Survival rates have reached 95%, but esophageal and respiratory morbidity during childhood is frequent. Child and parent perspectives and cultural and age-specific approaches are fundamental in understanding children's health-related quality of life (HRQoL) and when developing a pediatric HRQoL questionnaire. We aimed to increase the conceptual and cross-cultural understanding of condition-specific HRQoL experiences among EA children from Sweden and Germany and investigate content validity for an EA-specific HRQoL questionnaire. METHODS: Eighteen standardized focus groups (FGs) with 51 families of EA children aged 2-17 years in Sweden (n = 30 families) and Germany (n = 21 families) were used to explore HRQoL experiences, which were content analyzed into HRQoL domains. The Swedish HRQoL domains were analyzed first and used as framework to evaluate HRQoL content reported in the German FGs. HRQoL experiences were then categorized as physical, social, and emotional HRQoL burden or resource. RESULTS: One thousand nine hundred eight HRQoL statements were recorded. All nine EA-specific HRQoL domains identified in the Swedish FGs (eating, social relationships, general life issues, communication, body issues, bothersome symptoms, confidence, impact of medical treatment, and additional difficulties due to concomitant anomalies) were recognized in the FGs held in Germany, and no additional EA-specific HRQoL domain was found. The HRQoL dimensions referenced physical burden (n = 655, 34.5%), social burden (n = 497, 26.0%), social resources (n = 303, 15.9%), emotional burden (n = 210, 11.0%), physical resources (n = 158, 8.3%), and emotional resources (n = 85, 4.5%). CONCLUSION: This first international FG study to obtain the EA child and his or her parents' perspective on HRQoL suggests Swedish-German qualitative comparability of the HRQoL domains and content validity for a cross-cultural EA-specific HRQoL questionnaire. EA children make positive and negative HRQoL experiences, but prominently related to physical and social burden, which underlines appropriate follow-up care and future research.

Assessing cost-effectiveness of early intervention in Alzheimer's disease: An open-source modeling framework.

INTRODUCTION: We develop a framework to model disease progression across Alzheimer's disease (AD) and to assess the cost-effectiveness of future disease-modifying therapies (DMTs) for people with mild cognitive impairment (MCI) due to AD. METHODS: Using data from the US National Alzheimer's Coordinating Center, we apply survival analysis to estimate transition from predementia to AD dementia and ordered probit regression to estimate transitions across AD dementia stages. We investigate the cost-effectiveness of a hypothetical treatment scenario for people in MCI due to AD. RESULTS: We present an open-access model-based decision-analytic framework. Assuming a modest DMT treatment effect in MCI, we predict extended life expectancy and a reduction in time with AD dementia. DISCUSSION: Any future DMT for AD is expected to pose significant economic challenges across all health-care systems, and decision-analytic modeling will be required to assess costs and outcomes. Further developments are needed to inform these health policy considerations.

The Esophageal-Atresia-Quality-of-life Questionnaires: Feasibility, Validity and Reliability in Sweden and Germany.

OBJECTIVES: Esophageal atresia (EA) is a rare malformation characterized of discontinuity of the esophagus, concurrent with or without a tracheoesophageal fistula (TEF). We report the feasibility validity and reliability of a condition-specific quality-of-life (QOL) tool for EA/TEF children, the age-adapted EA-QOL-questionnaires, when used in Sweden and Germany. METHODS: A total of 124 families of children with EA/TEF participated in the study; 53 parents completed the EA-QOL-questionnaire for children aged 2 to 7 years; 62 children/71 parents the EA-QOL-questionnaire for children 8 to 17 years. Feasibility was determined from the percentage of missing item responses. Based on clinical data and previously validated generic QOL-instruments (PedsQL 4.0, DISABKIDS-12), the final EA-QOL scores were evaluated against hypotheses of validity (known-groups/concurrent/convergent) and reliability (internal consistency/retest reliability of scores for 3 weeks). Significant level was P < 0.05. RESULTS: In the questionnaire for EA/TEF children aged 2 to 7 years, 16/18 items were completed with missing values <6% (range 0%-7.5%), and in the questionnaire for 8 to 17-year-olds, 24/24 child-reported items (range 0%-4.8%) and 21/24 parent-reported items (range 0%-7.0%). In both age-specific EA-QOL-questionnaires, desirable standards for known-groups and concurrent validity were fulfilled; digestive symptoms and feeding difficulties negatively impacted EA-QOL-Total-scores (P < 0.001), and as hypothesized, in 2 to 7-year-olds, respiratory symptoms decreased EA-QOL-Total-scores (P = 0.002). Correlations between the EA-QOL and generic QOL questionnaires supported convergent validity. Internal consistency reliability was satisfactory. The level of agreements of EA-QOL-scores between the field- and retest study were good to excellent. CONCLUSIONS: The overall psychometric performance of the EA-QOL-questionnaires for EA/TEF children is satisfactory and can enhance outcome evaluations in future research and clinical practice.

Stirring the motivational soup: within-person latent profiles of motivation in exercise.

BACKGROUND: The purpose of the present study was to use a person-oriented analytical approach to identify latent motivational profiles, based on the different behavioural regulations for exercise, and to examine differences in satisfaction of basic psychological needs (competence, autonomy and relatedness) and exercise behaviour across these motivational profiles. METHODS: Two samples, consisting of 1084 and 511 adults respectively, completed exercise-related measures of behavioural regulation and psychological need satisfaction as well as exercise behaviour. Latent profile analyses were used to identify motivational profiles. RESULTS: Six profiles, representing different combinations of regulations for exercise, were found to best represent data in both samples. Some profiles were found in both samples (e.g., low motivation profile, self-determined motivation profile and self-determined with high introjected regulation profile), whereas others were unique to each sample. In line with the Self-Determination Theory, individuals belonging to more self-determined profiles demonstrated higher scores on need satisfaction. CONCLUSIONS: The results support the notions of motivation being a multidimensional construct and that people have different, sometimes competing, reasons for engaging in exercise. The benefits of using person-oriented analyses to examine within-person interactions of motivation and different regulations are discussed.

Inventory of real world data sources in Parkinson's disease.

BACKGROUND: Real world data have an important role to play in the evaluation of epidemiology and burden of disease; and in assisting health-care decision-makers, especially related to coverage and payment decisions. However, there is currently no overview of the existing longitudinal real world data sources in Parkinson's disease (PD) in the USA. Such an assessment can be very helpful, to support a future effort to harmonize real world data collection and use the available resources in an optimal way. METHODS: The objective of this comprehensive literature review is to systematically identify and describe the longitudinal, real world data sources in PD in the USA, and to provide a summary of their measurements (categorized into 8 main dimensions: motor and neurological functions, cognition, psychiatry, activities of daily living, sleep, quality of life, autonomic symptoms and other). The literature search was performed using MEDLINE, EMBASE and internet key word search. RESULTS: Of the 53 data sources identified between May and August 2016, 16 were still ongoing. Current medications (81%) and comorbidities (79%) were frequently collected, in comparison to medical imaging (36%), genetic information (30%), caregiver burden (11%) and healthcare costs (2%). Many different measurements (n = 108) were performed and an interesting variability among used measurements was revealed. CONCLUSIONS: Many longitudinal real world data sources on PD exist. Different types of measurements have been performed over time. To allow comparison and pooling of these multiple data sources, it will be essential to harmonize practices in terms of types of measurements.

The worldwide costs of dementia 2015 and comparisons with 2010.

INTRODUCTION: In 2010, Alzheimer's Disease International presented estimates of the global cost of illness (COI) of dementia. Since then, new studies have been conducted, and the number of people with dementia has increased. Here, we present an update of the global cost estimates. METHODS: This is a societal, prevalence-based global COI study. RESULTS: The worldwide costs of dementia were estimated at United States (US) $818 billion in 2015, an increase of 35% since 2010; 86% of the costs occur in high-income countries. Costs of informal care and the direct costs of social care still contribute similar proportions of total costs, whereas the costs in the medical sector are much lower. The threshold of US $1 trillion will be crossed by 2018. DISCUSSION: Worldwide costs of dementia are enormous and still inequitably distributed. The increase in costs arises from increases in numbers of people with dementia and in increases in per person costs.