Informal Care Costs Research Articles

The Valuation of Informal Care in Cost-of-Illness Studies: A Systematic Review.

There is a growing interest in incorporating informal care in cost-of-illness studies as a relevant part of the economic impact of some diseases. The aim of this paper was to review the recent literature valuating the costs of informal care in a group of selected diseases from 2005 to 2015. We carried out a systematic review on the economic impact of informal care, focusing on six selected diseases: arthritis or osteoarthritis, cancer, dementia, mental diseases, multiple sclerosis and stroke. We selected 91 cost-of-illness articles. The average weight attributed to the informal care cost over the total cost was highly relevant for dementia, stroke, mental diseases, cancer and multiple sclerosis. The most frequent valuation method applied was the opportunity cost method, followed by the proxy good method. The annual cost of informal care presented a high variability depending on the disease and geographic location. Distinguishing by type of illness, the disease with the highest annual value of informal caregiving was dementia, followed by mental illness and multiple sclerosis. The average hourly unit cost was €11.43 (2015 values), varying noticeably depending on the geographic location. This paper identifies several aspects that should be enhanced to promote comparability between studies and countries, and it sends key messages for incorporating informal care costs to adequately measure the economic impact of diseases.

PCV58 - The Economic Burden of Atrial Fibrillation in Latin America

The economic burden of atrial fibrillation (AF) in the Latin American region has not been previously quantified. This research assessed the economic burden of AF in Brazil, Chile, Colombia, Ecuador, El Salvador, Mexico, Panama, Peru, Venezuela. To estimate the cost of AF by country, a prevalence approach was used. Costs were estimated for the year 2015 and included health system expenditures, productivity losses (absenteeism, lower workforce participation, premature mortality) and informal care costs, and deadweight losses associated with government expenditures. Data inputs for costs, including prevalence and mortality were based on secondary data sources informed by a targeted literature review including country specific grey literature and data sources. The study also appraised the value of the loss of healthy life, measured in disability adjusted life years (DALYs), using global burden of disease disability weights. AF was found to affect approximately 2.7 million people (0.8% of the adult population, average of 69.5 years old) in selected Latin American countries in 2015. This leads to significant wellbeing loss, estimated at 664,460 DALYs, and economic burden, estimated at USD2.4 billion in 2015. Health system expenditures accounted for USD2.3billion (95%) and productivity costs USD115million (5%) of the total financial burden of AF. On average, health system expenditure represented 0.06% of total gross domestic product (GDP) across the nine countries with Brazil (0.07%), Chile (0.08%), Colombia (0.07%), Ecuador (0.06%) and El Salvador (0.13%) spending more than the average. Total financial costs averaged 0.06% of GDP. AF imposes a significant burden to the health system and society in Latin America. Health system expenditure accounts for the majority of the burden of AF in the region. Prevention and appropriate management of AF may result in substantial wellbeing benefits and economic savings.

PCV68 - The Economic Burden of Four Heart Conditions in Brazil

The economic burden of heart conditions in Brazil has not been previously quantified. This study assessed the economic burden of heart failure (HF), myocardial infarction (MI), atrial fibrillation (AF), and hypertension (HTN) in Brazil, and the cost effectiveness (CE) of telemedicine (TM) and structured telephone support (STS) for the treatment of HF. To estimate the cost of four heart conditions by country, a prevalence approach was used for HF, AF and HTN, and an incidence approach was used for MI. Costs were estimated for the year 2015 and included health system expenditures, productivity losses (absenteeism, lower workforce participation, premature mortality) and informal care costs, and deadweight losses associated with government expenditures. Data inputs for costs, including prevalence and incidence, were based on secondary data sources informed by a targeted literature review including country specific grey literature and data bases. The study also appraised the value of the loss of healthy life, measured in disability adjusted life years (DALYs), using global burden of disease disability weights. All inputs were triangulated using semi-structured interviews with clinicians, insurers and health administrators. The CE of TM and STS relative to usual care was assessed using a Markov model consisting of two permanent and two temporary health states. Accounting for co-morbidities, the conditions affected approximately 45.7 million people (32% of the adult population) in Brazil in 2015 leading to significant wellbeing loss, estimated at 3.2 million DALYs, and economic burden, estimated at BRL56.2 billion in 2015. The CE analysis suggested that TM and STS may both be cost effective treatment options for the management of patients with HF. Heart conditions impose a significant burden to the health system and society; their prevention and appropriate management would result in substantial wellbeing benefits and economic savings.

PCV65 - The Economic Burden of Hypertension in Latin America

The economic burden of hypertension (HTN) in the Latin American region has not been previously quantified. This research assessed the economic burden of HTN in Brazil, Chile, Colombia, Ecuador, El Salvador, Mexico, Panama, Peru, Venezuela. To estimate the cost of HTN by country, a prevalence approach was used. Costs were estimated for the year 2015 and included health system expenditures, productivity losses (absenteeism, lower workforce participation, premature mortality) and informal care costs, and deadweight losses associated with government expenditures. Data inputs for costs, including prevalence and mortality were based on secondary data sources informed by a targeted literature review including country specific grey literature and data sources. The study also appraised the value of the loss of healthy life, measured in disability adjusted life years (DALYs), using global burden of disease disability weights. HTN was found to affect approximately 86.7 million people (27% of the adult population, average of 54.3 years old) in selected Latin American countries in 2015 leading to significant wellbeing loss, estimated at 2.7 million DALYs, and economic burden, estimated at USD5.3 billion in 2015. Health system expenditures accounted for USD999 million (18%) and productivity costs USD4.3 billion (82%) of the total financial burden of AF. On average, health system expenditure represented 0.03% of total gross domestic product (GDP) across the nine countries with Colombia (0.04%), Ecuador (0.03%), El Salvador (0.08%), Mexico (0.03%) and Panama (0.04%) spending more than the average. Total financial costs averaged 0.12% of GDP. HTN imposes a significant burden to the health system and society in Latin America. Productivity losses account for the majority of the burden of HTN in the region. Prevention and appropriate management of HTN may result in substantial wellbeing benefits and economic savings.

PCV67 - The Economic Burden of Four Heart Conditions in Latin America

The economic burden of heart conditions in the Latin American region has not been previously quantified. This study assessed the economic burden of heart failure (HF), myocardial infarction (MI), atrial fibrillation (AF), and hypertension (HTN) in Brazil, Chile, Colombia, Ecuador, El Salvador, Mexico, Panama, Peru, Venezuela, and the cost effectiveness (CE) of structured telephone support (STS) and telemedicine (TM) for the treatment of HF. To estimate the cost of four heart conditions by country, a prevalence approach was used for HF, AF and HTN, and an incidence approach was used for MI. Costs were estimated for the year 2015 and included health system expenditures, productivity losses (absenteeism, lower workforce participation, premature mortality) and informal care costs, and deadweight losses associated with government expenditures. Data inputs for costs, including prevalence and incidence, were based on secondary data sources informed by a targeted literature review including country specific grey literature and data bases. The study also appraised the value of the loss of healthy life, measured in disability adjusted life years (DALYs), using global burden of disease disability weights. All inputs were triangulated using semi-structured interviews with clinicians, insurers and health administrators. The CE of TM and STS vs. usual care was assessed using a Markov model consisting of two permanent and two temporary health states. Accounting for co-morbidities, the conditions affected approximately 89.6 million people (28% of the adult population) in the nine countries in 2015 leading to significant wellbeing loss of 7.0 million DALYs, and economic burden of USD 31.1 billion in 2015. The CE analysis suggested TM and STS may be cost effective treatment options for the management of HF. Heart conditions impose a significant burden to health systems and society; their prevention and appropriate management would result in substantial wellbeing benefits and economic savings

PCV63 - The Economic Burden of Four Heart Conditions in Mexico

The economic burden of heart conditions in Mexico has not been previously quantified. This research assessed the economic burden of heart failure (HF), myocardial infarction (MI), atrial fibrillation (AF), and hypertension (HTN) in Mexico, and the cost effectiveness (CE) of telemedicine (TM) and structured telephone support (STS) for the treatment of HF. To estimate the cost of four heart conditions by country, a prevalence approach was used for HF, AF and HTN, and an incidence approach was used for MI. Costs were estimated for the year 2015 and included health system expenditures, productivity losses (absenteeism, lower workforce participation, premature mortality) and informal care costs, and deadweight losses associated with government expenditures. Data inputs for costs, including prevalence and incidence, were based on secondary data sources informed by a targeted literature review including country specific grey literature and data bases. The study also appraised the value of the loss of healthy life, measured in disability adjusted life years (DALYs), using global burden of disease disability weights. All inputs were triangulated using semi-structured interviews with clinicians, insurers and health administrators. The CE of TM and STS relative to usual care was assessed using a Markov model consisting of two permanent and two temporary health states. Accounting for co-morbidities, the conditions affected approximately 20.5 million people (25.6% of the adult population) in Mexico in 2015 leading to significant wellbeing loss, estimated at 1.6 million DALYs, and economic burden, estimated at MXN96.4 billion in 2015. TM and STS were found to be cost effective treatment options for the management of HF. Heart conditions impose a significant burden to the health system and society; their prevention and appropriate management would result in substantial wellbeing benefits and economic savings. TM and STS are cost effective mechanisms for achieving improvements in HF management.

PRM44 - A General Model for The Estimation of Societal Costs of Lost Production and Informal Care In Italy

We developed a general model for estimating and comparing disease- and treatment-specific lost paid/unpaid production (due to premature death and reduced ability) and informal care received (due to reduced ability) in Italy, starting from survival, demographic and Health-Related Quality of Life (HRQoL) data. Assuming the disease is not selecting a systematically different population in terms of mean wage than the general public, age- and gender-specific yearly production values are estimated combining data from the last Italian Time-Use-Survey on time dedicated to paid and unpaid (household, caring and volunteering) activities, with a) the last Italian Wage-Structure-Survey, for paid activities (Human Capital approach), and b) market prices for an equivalent service, for unpaid production (Proxy Good approach). To avoid double counting, age- and gender-specific maximum care needs are approximated with time dedicated to eating and personal care, reported in TUS. Present monetary values of future productivity and informal care are estimated applying a 3.5% annual discount rate. Lost life years due to a particular condition/treatment are estimated by comparison of its survival curve with the corresponding age- and gender-normalized survival curve of the general Italian population. The degrees of reduced productivity and need for informal care for remaining life years are estimated by comparison of condition-/treatment-specific reported HRQoL data with demographically matched Italian norms. Our results will be useful for cost-effectiveness and budget impact analyses conducted from the perspective of the Italian society and we encourage the inclusion of these costs in economic evaluations to allow decision makers to be fully informed about the costs and consequences of their decisions on healthcare interventions.

Financial Incentives to Stimulate Integration of Care.

Introduction Chronic conditions are related to 60% of disability adjusted life years and account for 75% of total health care expenditure worldwide. The economic burden of chronic conditions is much larger when considering the costs of productivity loss and informal care. The threat that chronic conditions pose to population health and economies increase because of increasing prevalence and multi-morbidity, which multiplies the burden of chronic conditions. Integrated care is seen as the means to tackle this threat by improving population health and patient experience with care, and reducing costs. It includes initiatives that seek to improve outcomes for those with (complex) chronic health problems and needs by overcoming issues of fragmentation through linkage or coordination of services of different providers along the continuum of care. In the era of personalized medicine and genomics, integrated care may be characterized by the recently suggested term ‘humanomics’ because it incorporates treatment based on personal need, preferences and capacity, it interacts with the context in which it is implemented, and its success depends highly on human behaviour [1]. Financial incentives are one of the main prerequisites for integrating care [2].

Economic burden of informal care attributable to stroke among those aged 65 years or older in China.

Stroke is a leading cause of disability in China, frequently resulting in the need for informal care. No information, however, is available on costs of informal care associated with stroke, required to understand the true cost of stroke in China. Using the 2011 China Health and Retirement Longitudinal Study, we identified 4447 respondents aged ≥65 years suitable for analyses, including 184 stroke survivors. We estimated the economic burden of informal care associated with stroke using a two-part model. The monthly number of hours of informal caregiving associated with stroke was 29.2 h/stroke survivor, and the average annual cost of informal care associated with stroke was 10,612 RMB per stroke survivor. The findings stress the necessity of proper interventions to prevent stroke and will be useful for estimating the economic burden of stroke.

The economic burden of dementia in China, 1990-2030: implications for health policy.

ObjectiveTo quantify and predict the economic burden of dementia in China for the periods 1990–2010 and 2020–2030, respectively, and discuss the potential implications for national public health policy.MethodsUsing a societal, prevalence-based, gross cost-of-illness approach and data from multiple sources, we estimated or predicted total annual economic costs of dementia in China. We included direct medical costs in outpatient and inpatient settings, direct non-medical costs – e.g. the costs of transportation – and indirect costs due to loss of productivity. We excluded comorbidity-related costs.FindingsThe estimated total annual costs of dementia in China increased from 0.9 billion United States dollars (US$) in 1990 to US$ 47.2 billion in 2010 and were predicted to reach US$ 69.0 billion in 2020 and US$ 114.2 billion in 2030. The costs of informal care accounted for 94.4%, 92.9% and 81.3% of the total estimated costs in 1990, 2000 and 2010, respectively. In China, population ageing and the increasing prevalence of dementia were the main drivers for the increasing predicted costs of dementia between 2010 and 2020, and population ageing was the major factor contributing to the growth of dementia costs between 2020 and 2030.ConclusionIn China, demographic and epidemiological transitions have driven the growth observed in the economic costs of dementia since the 1990s. If the future costs of dementia are to be reduced, China needs a nationwide dementia action plan to develop an integrated health and social care system and to promote primary and secondary prevention.

Consequences of Anosognosia on the Cost of Caregivers' Care in Alzheimer's Disease.

Anosognosia is common in patients with Alzheimer's disease (AD) and it is frequently related to an increase in time of care demand. The aim of the study was to examine the effect of anosognosia on the total costs of informal care in patients with AD. This was a prospective longitudinal study with community-dwelling AD patients. Anosognosia, time of informal care, and the use of support services (e.g., day care centers) were recorded at baseline and after 24 months. The cost of informal caregiving was calculated as 'market price'. At baseline, the prevalence of anosognosia was 54.3% (n = 221), and 43.9% were classified as mild-AD. The average time of care was 5 h/day±2.4 (IADL: 1.3 h/day±1.4 and BADL: 3.6 h/day±1.5). Thirty percent of the patients used home care services, and 25.1% attended a day care center. Patients with anosognosia received more time of care and were more likely to use support services than did their no-anosognosia peers, including institutionalization. The mean cost of support services was 490.4€ /month (SD = 413.1€; range = 25-2,212.38€), while the overall cost of care (support services plus informal care) was 1,787€ /month (SD = 972.4€), ranging from 834.1€ in mild-AD without anosognosia patients, to 2,424.8€ in severe-AD with incident anosognosia patients. Anosognosia was associated with an increased number of hours of informal care, and a greater use of support services, regardless of the severity of the dementia, which lead to an increase of the total family-care costs.

The Cost-Effectiveness of Two Forms of Case Management Compared to a Control Group for Persons with Dementia and Their Informal Caregivers from a Societal Perspective.

ObjectivesThe objective of this article was to compare the costs and cost-effectiveness of the two most prominent types of case management in the Netherlands (intensive case management and linkage models) against no access to case management (control group) for people with already diagnosed dementia and their informal caregivers.MethodsThe economic evaluation was conducted from a societal perspective embedded within a two year prospective, observational, controlled, cohort study with 521 informal caregivers and community-dwelling persons with dementia. Case management provided within one care organization (intensive case management model, ICMM), case management where care was provided by different care organizations within one region (Linkage model, LM), and a group with no access to case management (control) were compared. The economic evaluation related incremental costs to incremental effects regarding neuropsychiatric symptoms (NPI), psychological health of the informal caregiver (GHQ-12), and quality adjusted life years (QALY) of the person with dementia and informal caregiver.ResultsInverse-propensity-score-weighted models showed no significant differences in clinical or total cost outcomes between the three groups. Informal care costs were significantly lower in the ICMM group compared to both other groups. Day center costs were significantly lower in the ICMM group compared to the control group. For all outcomes, the probability that the ICMM was cost-effective in comparison with LM and the control group was larger than 0.97 at a threshold ratio of 0 €/incremental unit of effect.ConclusionThis study provides preliminary evidence that the ICMM is cost-effective compared to the control group and the LM. However, the findings should be interpreted with caution since this study was not a randomized controlled trial.

Admission avoidance hospital at home.

Admission avoidance hospital at home provides active treatment by healthcare professionals in the patient's home for a condition that otherwise would require acute hospital inpatient care, and always for a limited time period. This is the third update of the original review. To determine the effectiveness and cost of managing patients with admission avoidance hospital at home compared with inpatient hospital care. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, two other databases, and two trials registers on 2 March 2016. We checked the reference lists of eligible articles. We sought unpublished studies by contacting providers and researchers who were known to be involved in the field. Randomised controlled trials recruiting participants aged 18 years and over. Studies comparing admission avoidance hospital at home with acute hospital inpatient care. We followed the standard methodological procedures expected by Cochrane and the Effective Practice and Organisation of Care (EPOC) Group. We performed meta-analysis for trials that compared similar interventions and reported comparable outcomes with sufficient data, requested individual patient data from trialists, and relied on published data when this was not available. We used the GRADE approach to assess the certainty of the body of evidence for the most important outcomes. We included 16 randomised controlled trials with a total of 1814 participants; three trials recruited participants with chronic obstructive pulmonary disease, two trials recruited participants recovering from a stroke, six trials recruited participants with an acute medical condition who were mainly elderly, and the remaining trials recruited participants with a mix of conditions. We assessed the majority of the included studies as at low risk of selection, detection, and attrition bias, and unclear for selective reporting and performance bias. Admission avoidance hospital at home probably makes little or no difference on mortality at six months' follow-up (risk ratio (RR) 0.77, 95% confidence interval (CI) 0.60 to 0.99; P = 0.04; I2 = 0%; 912 participants; moderate-certainty evidence), little or no difference on the likelihood of being transferred (or readmitted) to hospital (RR 0.98, 95% CI 0.77 to 1.23; P = 0.84; I2 = 28%; 834 participants; moderate-certainty evidence), and may reduce the likelihood of living in residential care at six months' follow-up (RR 0.35, 95% CI 0.22 to 0.57; P < 0.0001; I2 = 78%; 727 participants; low-certainty evidence). Satisfaction with healthcare received may be improved with admission avoidance hospital at home (646 participants, low-certainty evidence); few studies reported the effect on caregivers. When the costs of informal care were excluded, admission avoidance hospital at home may be less expensive than admission to an acute hospital ward (287 participants, low-certainty evidence); there was variation in the reduction of hospital length of stay, estimates ranged from a mean difference of -8.09 days (95% CI -14.34 to -1.85) in a trial recruiting older people with varied health problems, to a mean increase of 15.90 days (95% CI 8.10 to 23.70) in a study that recruited patients recovering from a stroke. Admission avoidance hospital at home, with the option of transfer to hospital, may provide an effective alternative to inpatient care for a select group of elderly patients requiring hospital admission. However, the evidence is limited by the small randomised controlled trials included in the review, which adds a degree of imprecision to the results for the main outcomes.

The worldwide costs of dementia 2015 and comparisons with 2010

IntroductionIn 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. MethodsThis is a societal, prevalence-based global COI study. ResultsThe 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. DiscussionWorldwide 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.

Costs of formal and informal care at home for people with dementia: 'Expert panel' opinions from staff and informal carers.

Effective home support in dementia is key in delaying nursing home admission. However, home support is frequently not tailored to the individual needs of people with dementia. Staff allocating home support services may not identify important care needs, which only be recognised by informal carers. The purpose of this study was to explore the balance of informal and formal home support and their associated costs from the perspectives of both informal carers and paid staff. Five case vignettes of people with dementia were designed based on an existing English data set from a European study into transition into long-term care (the RightTimePlaceCare programme), representing 42 per cent of the English sample. In total, 14 informal carers and 14 paid staff were consulted in separate groups, as expert panels, regarding their recommendations for home care services for each vignette. Care recommendations of carers and staff were costed based on nationally available unit costs and compared. Informal carers allocated fewer hours of care than staff. Personal and domestic home care and day care centres were the most frequently recommended formal services by both groups, and some vignettes of people with dementia were recommended for care home admission. The ratio of costs of informal versus formal support was relatively equal for paid staff, yet unbalanced from the perspectives of informal carers with a greater proportion of formal care costs. Recommendations from this study can help shape dementia care to be more tailored to the individual needs of people with dementia and their carers.

The Social Costs of Dementia in Japan: Focusing on the Informal Care Cost

Due to the rapid increase of the number in people with dementia, social costs of dementia are also expected to rise. In 2014, the social cost of dementia in Japan was estimated to be 145,140 billion yen, 40 % of which was spent on informal care. To investigate whether each intervention is worth the investment, more research on aspects like cost-effective analysis is expected to be undertaken.

Economic burden of malignant blood disorders across Europe: a population-based cost analysis

Malignant blood disorders are a leading contributor to cancer incidence and mortality across Europe. Despite their burden, no study has assessed the economic effect of blood cancers in Europe. We aimed to assess the economic burden of malignant blood disorders across the 28 countries in the European Union (EU), Iceland, Norway, and Switzerland. Malignant blood disorder-related costs were estimated for 28 EU countries, Iceland, Norway, and Switzerland for 2012. Country-specific costs were estimated with aggregate data on morbidity, mortality, and health-care resource use obtained from international and national sources. Health-care costs were estimated from expenditure on primary, outpatient, emergency, inpatient care, and drugs. Costs of informal care and productivity losses due to morbidity and early death were also included. For countries in the EU, malignant blood disorders were compared with the economic burden of overall cancer. Malignant blood disorders cost the 31 European countries €12 billion in 2012. Health-care cost €7·3 billion (62% of total costs), productivity losses cost €3·6 billion (30%), and informal care cost €1 billion (8%). For the EU countries, malignant blood disorders cost €6·8 billion (12%) of the total health-care expenditure on cancer (€57 billion), with this proportion being second only to breast cancer. In terms of total cancer costs in the EU (€143 billion), malignant blood disorders cost €12 billion (8%). Malignant blood disorders represent a leading cause of death, health-care service use, and costs, not only to European health-care systems, but to society overall. Our results add to essential public health knowledge needed for effective national cancer-control planning and priorities for public research funding. European Hematology Association.

Economic burden of non-malignant blood disorders across Europe: a population-based cost study

Blood disorders comprise a wide range of diseases including anaemia, malignant blood disorders, and haemorrhagic disorders. Although they are a common cause of disease, no systematic cost-of-illness studies have been done to assess the economic effect of non-malignant blood disorders in Europe. We aimed to assess the economic burden of non-malignant blood disorders across the 28 countries of the European Union (EU), Iceland, Norway, and Switzerland. Non-malignant blood disorder-related costs (WHO International Classification of Diseases, 10th revision [ICD] D50-89) were estimated for 28 EU countries, Iceland, Norway, and Switzerland for 2012. Country-specific costs were estimated with aggregate data on morbidity, mortality, and health-care resource use obtained from international and national sources. Health-care costs were estimated from expenditure on primary care, outpatient care, emergency care, hospital inpatient care, and drugs. Costs of informal care and productivity losses due to morbidity and early death were also included. To these costs we added those due to malignant blood disorders (ICD-10 C81-96 and D47) as estimated in a Burns and colleagues' companion Article to obtain the total costs of blood disorders. Non-malignant disorders of the blood cost the 31 European countries €11 billion in 2012. Health-care costs accounted for €8 billion (75% of total costs), productivity losses for €2 billion (19%), and informal care for less than €1 billion (6%). Averaged across the European population studied, non-malignant disorders of the blood represented an annual health-care cost of €159 per ten citizens. Combining malignant and non-malignant blood disorders, the total cost of blood disorders was €23 billion in 2012. Our study highlights the economic burden that non-malignant blood disorders place on European health-care systems and societies. Our study also shows that blood disorder costs were evenly distributed between malignant and non-malignant blood disorders. Our results should be of use to decision makers and research-funding authorities charged with allocating health-care resources and research funds. European Hematology Association.

How to deal with missing longitudinal data in cost of illness analysis in Alzheimer's disease-suggestions from the GERAS observational study.

BackgroundMissing data are a common problem in prospective studies with a long follow-up, and the volume, pattern and reasons for missing data may be relevant when estimating the cost of illness. We aimed to evaluate the effects of different methods for dealing with missing longitudinal cost data and for costing caregiver time on total societal costs in Alzheimer’s disease (AD).MethodsGERAS is an 18-month observational study of costs associated with AD. Total societal costs included patient health and social care costs, and caregiver health and informal care costs. Missing data were classified as missing completely at random (MCAR), missing at random (MAR) or missing not at random (MNAR). Simulation datasets were generated from baseline data with 10–40 % missing total cost data for each missing data mechanism. Datasets were also simulated to reflect the missing cost data pattern at 18 months using MAR and MNAR assumptions. Naïve and multiple imputation (MI) methods were applied to each dataset and results compared with complete GERAS 18-month cost data. Opportunity and replacement cost approaches were used for caregiver time, which was costed with and without supervision included and with time for working caregivers only being costed.ResultsTotal costs were available for 99.4 % of 1497 patients at baseline. For MCAR datasets, naïve methods performed as well as MI methods. For MAR, MI methods performed better than naïve methods. All imputation approaches were poor for MNAR data. For all approaches, percentage bias increased with missing data volume. For datasets reflecting 18-month patterns, a combination of imputation methods provided more accurate cost estimates (e.g. bias: −1 % vs −6 % for single MI method), although different approaches to costing caregiver time had a greater impact on estimated costs (29–43 % increase over base case estimate).ConclusionsMethods used to impute missing cost data in AD will impact on accuracy of cost estimates although varying approaches to costing informal caregiver time has the greatest impact on total costs. Tailoring imputation methods to the reason for missing data will further our understanding of the best analytical approach for studies involving cost outcomes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12874-016-0188-1) contains supplementary material, which is available to authorized users.

THE ROLE OF DEPENDENCE IN ALZHEIMER’S DISEASE DEMENTIA: A SYSTEMATIC LITERATURE REVIEW

Evaluation of dependence has been suggested as a potential method for translating the effect of changes in cognition, function, and behavior into a more holistic description of AD progression. This review evaluates the existing literature regarding the overall concept of dependence, its measurement, and its relationship with longitudinal outcomes. A systematic review of peer-reviewed articles published between January 1995 and October 2015 was performed using MEDLINE, EMBASE, and the Cochrane Central Library of Controlled Trials. Randomized clinical trials and observational studies evaluating ≥50 patients were included. Outcomes of interest included changes in dependence over time, the impact of dependence on changes in cognition, function, behavior, and quality of life, and the associated economic burden of dependence. 185 full-text references were reviewed, and 38 publications were identified for inclusion. Most publications focused on data sets from prospective, observational trials including the Predictors Study (n=11), the Enhancing Care in Alzheimer's Disease (ECAD) study (n=4), the Co-Dependence in Alzheimer's Disease (CoDep-AD) study (n=2), the Dependence in Alzheimer's Disease in England (DADE) study (n=2), and the ELN-AIP-901 study (n=2). The most frequently used measurement was the Dependence Scale (DS) (n=33). Over a range of follow-up durations (1.5 to 6 years), dependence significantly increased over time, with greater changes reported among patients with more severe disease. Among patients with mild to moderate AD (mean baseline DS = 5.3-5.4, based on sum of items {0,15}), DS scores significantly increased over 6 to 12 months, with mean changes reported ranging from 0.5 to 1 point. Dependence was found to be significantly correlated with clinical variables including cognition, function, quality of life (QoL), and caregiver burden. While the association between changes in dependence and QoL varied by study, caregiver burden was consistently shown to increase with patient dependence. Dependence was also significantly associated with direct, informal care, and total care costs. This review clarifies the relationship between dependence and the clinical, quality of life and economic burden of AD, and corroborates previous understanding that dependence may translate the effect of changes in symptoms into a more holistic description of AD and its progression.