Cost-of-illness studies : a review of current methods

Cost-of-illness studies: a guide to critical evaluation

Cost-of-illness (COI) studies aim to assess the economic burden of health problems on the population overall, and they are conducted for an ever widening range of health conditions and geographical settings. While they attract much interest from public health advocates and healthcare policy makers, inconsistencies in the way in which they are conducted and a lack of transparency in reporting have made interpretation difficult, and have ostensibly limited their usefulness. Yet there is surprisingly little in the literature to assist the non-expert in critically evaluating these studies. This article aims to provide non-expert readers with a straightforward guide to understanding and evaluating traditional COI studies. The intention is to equip a general audience with an understanding of the most important issues that influence the validity of a COI study, and the ability to recognize the most common limitations in such work.

Relative weight-related costs of healthcare use by children--results from the two German birth cohorts, GINI-plus and LISA-plus

Obesity among children and adolescents is a growing public health burden. According to a national reference among German children and adolescents aged 3-17 years, 15% are overweight (including obese) and 6.3% are obese. This study aims to assess the economic burden associated with overweight and obesity in children based on a cross-sectional survey from two birth cohort studies: the GINI-plus - German Infant Nutritional Intervention plus Non-Intervention study (3287 respondents aged 9 to <12 years) and the LISA-plus study - Influence of life-style factors on the development of the immune system and allergies in East and West Germany (1762 respondents aged 9 to <12 years). Using a bottom-up approach, we analyse direct costs induced by the utilisation of healthcare services and indirect costs emerging from parents' productivity losses. To investigate the impact of Body Mass Index (BMI) on costs, we perform various descriptive analyses and estimate a two-part regression model. Average annual total direct medical costs of healthcare use are estimated to be €418 (95% CI [346-511]) per child, split between physician (22%), therapist (29%), hospital (41%) and inpatient rehabilitation costs (8%). Bivariate analysis shows considerable differences between BMI groups: €469 (severely underweight), €468 (underweight), €402 (normal weight), €468 (overweight) and €680 (obese). Indirect costs make up €101 per year on average and tend to be higher for obese children, although this was not statistically significant. Drawing on these results, differences in healthcare costs between BMI groups are already apparent in children.

Overactive Bladder Syndrome: The Social and Economic Perspective

Overactive bladder syndrome (OAB) is a highly prevalent condition associated with a significant impairment of patients’ Quality of Life (QoL) because of its adverse effects on social, sexual, interpersonal, and professional functions. Cost-of-illness analyses showed the huge economic burden related to OAB for patients, public healthcare systems, and society, secondary to both direct and indirect costs. These types of cost analyses, however, exclude intangible costs related to QoL impairment. Recently, many novel therapies have been introduced, arising the need to apply the modern methodology of Health Technology Assessment (HTA) to new therapies in order to evaluate objectively their value in terms of both improvement in length/Quality of Life and costs. By producing information on the clinical, economic, organizational, social and ethical impact of health technologies, HTA has been used worldwide to inform decision makers at different levels in health systems. The HTA approach demonstrated, worldwide, to be a useful approach to increase the level of appropriateness in the use of medical technology and, as a consequence of that, of resources. Health utilities are instruments that allow a measurement of QoL and its integration in the economic evaluation using the Quality-of-life-Adjusted-Life-Years (QALYs) model and cost-utility analysis. The development of suitable instruments for quantifying utility in the specific group of OAB patients is vitally important to extend the application of cost-utility analysis in OAB and to guide healthcare resources allocation for this disorder. Studies are required to define the cost-effectiveness of available pharmacological and non-pharmacological therapy options.

General population versus disease-specific event rate and cost estimates: potential bias for economic appraisals

Economic appraisals are increasingly being used for reimbursement decision making. Differences exist in the population data sources used in different studies and these differences may result in errors or biased estimates. A review of the literature suggests that very little has been written on this topic and guidelines and good practice documents are silent on the issue. Using illustrative examples, it was found that the population chosen for event/complication costing did not have a large impact on a cost-effectiveness analysis; however, the choice of population did have a large impact for cost-of-illness (COI) estimation. It was found that not controlling for event/complication rates in a nondiseased population resulted in a 15% inflated COI estimate and using event costs from the general population underestimated COI by 20-32%. Our analysis suggests that using event costs from the general population instead of a diseased population may not have a significant impact on cost-effectiveness estimates; however, COI studies should only use excess event/complication rates and should also only use event costs from populations with the disease.

Excessive costs of COPD in ever-smokers. A longitudinal community study

AIM

We aimed to estimate the societal treatment-related costs of COPD in hospital- and population-based subjects with spirometry defined COPD, relative to a control group.

METHODS

81 COPD cases and 132 controls without COPD were randomly recruited from a general population, as were 205 COPD patients from a hospital register. All participants were ever-smokers of at least 40 years of age, followed for 12 months. Data on comorbid conditions and spirometry were collected at baseline. Standardized telephone interviews every third month gave information on use of healthcare services and exacerbations of respiratory symptoms.

RESULTS

The increased (excessive) median annual costs per case having stage II, stage III and stage IV COPD were € (95% CI) 400 (105-695), 1918 (1268-2569) and 1870 (1031-2709), respectively, compared to the population-based controls. Costs increased with €81 (95% CI 50-112) per exacerbation of respiratory symptoms and €461 (95% CI 354-567) per comorbid condition. Excessive costs for hospital COPD patients were threefold that of the population-based COPD cases.

CONCLUSION

The excessive treatment-related cost of COPD stage II+ in ever-smokers of at least 40 years was estimated to €105 million for Norway. Comorbidity was a dominant predictor of excessive cost in COPD.

Economics of type 1 diabetes

This article reviews economic methodologies developed for estimating cost of illness, examines the current literature on diabetes costs, and presents the latest estimates of the economic impact of type 1 diabetes in terms of direct medical costs (ie, treatment costs) and indirect costs (eg, lost wages).

Estimating the cost of type 1 diabetes in the U.S.: a propensity score matching method

BACKGROUND

Diabetes costs represent a large burden to both patients and the health care system. However, few studies that examine the economic consequences of diabetes have distinguished between the two major forms, type 1 and type 2 diabetes, despite differences in underlying pathologies. Combining the two diseases implies that there is no difference between the costs of type 1 and type 2 diabetes to a patient. In this study, we examine the costs of type 1 diabetes, which is often overlooked due to the larger population of type 2 patients, and compare them to the estimated costs of diabetes reported in the literature.

METHODOLOGY/PRINCIPAL FINDINGS

Using a nationally representative dataset, we estimate yearly and lifetime medical and indirect costs of type 1 diabetes by implementing a matching method to compare a patient with type 1 diabetes to a similar individual without the disease. We find that each year type 1 diabetes costs this country $14.4 billion (11.5-17.3) in medical costs and lost income. In terms of lost income, type 1 patients incur a disproportionate share of type 1 and type 2 costs. Further, if the disease were eliminated by therapeutic intervention, an estimated $10.6 billion (7.2-14.0) incurred by a new cohort and $422.9 billion (327.2-519.4) incurred by the existing number of type 1 diabetic patients over their lifetime would be avoided.

CONCLUSIONS/SIGNIFICANCE

We find that the costs attributed to type 1 diabetes are disproportionately higher than the number of type 1 patients compared with type 2 patients, suggesting that combining the two diseases when estimating costs is not appropriate. This study and another recent contribution provides a necessary first step in estimating the substantial costs of type 1 diabetes on the U.S.

Salmonella Typhimurium and Salmonella Enteritidis in England: costs to patients, their families, and primary and community health services of the NHS

This is the first study comparing societal costs of acute illness with Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE) in the UK. It included the cost and severity of the illness and explored the impact of each Salmonella serovar on the patients, their families, the NHS, and the wider economy. The study ascertained confirmed cases of ST and SE between July and November 2008. The mean costs per case were £1282 (ST) and £993 (SE). The indirect costs associated with the work-time lost by the case, parents, or carers were £409 (ST) and £228 (SE); this difference was statistically significant. The aggregate cost of ST and SE identified using laboratory test results for the UK as a whole was estimated as £6.5 million. Work-time lost and caring activities are cost categories that are not frequently investigated within the infectious intestinal disease literature, although they represent an important societal cost.

Burden of disease and costs of aneurysmal subarachnoid haemorrhage (aSAH) in the United Kingdom

Background

To estimate life years and quality-adjusted life years (QALYs) lost and the economic burden of aneurysmal subarachnoid haemorrhage (aSAH) in the United Kingdom including healthcare and non-healthcare costs from a societal perspective.

Methods

All UK residents in 2005 with aSAH (International Classification of Diseases 10^th revision (ICD-10) code I60). Sex and age-specific abridged life tables were generated for a general population and aSAH cohorts. QALYs in each cohort were calculated adjusting the life tables with health-related quality of life (HRQL) data. Healthcare costs included hospital expenditure, cerebrovascular rehabilitation, primary care and community health and social services. Non-healthcare costs included informal care and productivity losses arising from morbidity and premature death.

Results

A total of 80,356 life years and 74,807 quality-adjusted life years were estimated to be lost due to aSAH in the UK in 2005. aSAH costs the National Health Service (NHS) £168.2 million annually with hospital inpatient admissions accounting for 59%, community health and social services for 18%, aSAH-related operations for 15% and cerebrovascular rehabilitation for 6% of the total NHS estimated costs. The average per patient cost for the NHS was estimated to be £23,294. The total economic burden (including informal care and using the human capital method to estimate production losses) of a SAH in the United Kingdom was estimated to be £510 million annually.

Conclusion

The economic and disease burden of aSAH in the United Kingdom is reported in this study. Decision-makers can use these results to complement other information when informing prevention policies in this field and to relate health care expenditures to disease categories.

Cost-of-illness studies of dementia: a systematic review focusing on stage dependency of costs

OBJECTIVE

To review cost-of-illness (COI) studies of dementia from Europe and North America which report costs per patient by disease stage.

METHOD

A systematic literature search was performed in electronic databases. Studies were classified according to important determinants of costs. Results were converted into year 2006 USD-PPP, and summarized as costs for formal and informal care in mild, moderate and severe dementia.

RESULTS

28 studies were evaluated. They used a wide range of methods. Costs more than doubled from mild to severe dementia. Patterns and size of estimated costs depended primarily on study objectives (estimation of total costs-net costs), living arrangements of patients (community-dwelling-institutionalized) and inclusion of informal care.

CONCLUSION

This review is the first to have focused on costs in different stages of dementia. The stage is an important determinant of costs. However, characteristics of individual studies need to be considered, when making use of their results.

Social, economic, and health utility considerations in the treatment of overactive bladder

Overactive bladder (OAB) is a highly prevalent urinary syndrome with a profound impact on quality of life (QoL) of affected patients and their family because of its adverse effects on social, sexual, interpersonal, and professional function. Cost-of-illness analyses showed the huge economic burden related to OAB for patients, public healthcare systems, and society, secondary to both direct and indirect costs; however, intangible costs related to QoL impact are usually omitted from these analyses. Recently many novel treatment modalities have been introduced and the need to apply the modern methodology of health technology assessment to these treatment strategies was immediately clear in order to evaluate objectively their value in term of both improvement in length/quality of life and costs. Health utilities are instruments that allow a measurement of QoL and its integration in the economic evaluation using the quality-adjusted life-years model and cost-utility analysis. The development of suitable instruments for quantifying utility in the specific group of OAB patients is vitally important to extend the application of cost-utility analysis in OAB and to guide healthcare resources allocation for this disorder. Studies are required to define the cost-effectiveness of available pharmacological and nonpharmacological therapy options for this disorder.

Social, economic, and health utility considerations in the treatment of overactive bladder

Overactive bladder (OAB) is a highly prevalent urinary syndrome with a profound impact on quality of life (QoL) of affected patients and their family because of its adverse effects on social, sexual, interpersonal, and professional function. Cost-of-illness analyses showed the huge economic burden related to OAB for patients, public healthcare systems, and society, secondary to both direct and indirect costs; however, intangible costs related to QoL impact are usually omitted from these analyses. Recently many novel treatment modalities have been introduced and the need to apply the modern methodology of health technology assessment to these treatment strategies was immediately clear in order to evaluate objectively their value in term of both improvement in length/quality of life and costs. Health utilities are instruments that allow a measurement of QoL and its integration in the economic evaluation using the quality-adjusted life-years model and cost-utility analysis. The development of suitable instruments for quantifying utility in the specific group of OAB patients is vitally important to extend the application of cost-utility analysis in OAB and to guide healthcare resources allocation for this disorder. Studies are required to define the cost-effectiveness of available pharmacological and nonpharmacological therapy options for this disorder.

Economic burden of multiple sclerosis: a systematic review of the literature

Multiple sclerosis (MS) is a disease of the CNS, typically striking adults during the primary productive time of their life. The symptoms of MS can restrict the individual's physical activity and income-earning ability, resulting in a major financial burden on the patient, family, health system and society. This systematic literature review was conducted to document the economic burden of MS. Employing pre-defined search terms and inclusion/exclusion criteria, systematic searches were conducted in MEDLINE, EMBASE, PsycINFO, the Health Economic Evaluations Database (HEED), the NHS Economic Evaluation Database (EED) and the UK National Institute for Health and Clinical Excellence (NICE) website as well as conference abstracts. We identified 29 cost-of-illness studies that met the a priori inclusion criteria. The cost categories responsible for the majority of costs associated with MS varied across countries. There was a significant increase in costs associated with an increase in disease severity as measured by the Kurtzke Expanded Disability Status Scale (EDSS) score. The increase in magnitude was coupled with changes in the distribution of costs; although direct medical costs were important contributors in earlier stages of disease, they were outweighed by indirect costs in later stages, mainly due to relapses and productivity losses. Considering the increased costs associated with relapse occurrence and increasing disease severity, pharmaceutical or non-pharmaceutical interventions aimed at delaying the progression of disease may help to reduce the economic burden of MS.

Direct and indirect costs of non-vertebral fracture patients with osteoporosis in the US

Osteoporosis is a condition marked by low bone mineral density and the deterioration of bone tissue. One of the main clinical and economic consequences of osteoporosis is skeletal fractures. To assess the healthcare and work loss costs of US patients with non-vertebral (NV) osteoporotic fractures. Privately insured (aged 18-64 years) and Medicare (aged >/=65 years) patients with osteoporosis (ICD-9-CM code: 733.0x) were identified during 1999-2006 using two claims databases. Patients with an NV fracture (femur, pelvis, lower leg, upper arm, forearm, rib or hip) were matched randomly on age, sex, employment status and geographic region to controls with osteoporosis and no fractures. Patient characteristics and annual healthcare costs were assessed over the year following the index fracture for privately insured (n = 4764) and Medicare (n = 48 742) beneficiaries (Medicare drug costs were estimated using multivariable models). Indirect (i.e. work loss) costs were calculated for a subset of privately insured, employed patients with available disability data (n = 1148). All costs were reported in $US, year 2006 values. In Medicare, mean incremental healthcare costs per NV fracture patient were $US13 387 ($US22 466 vs $US9079; p < 0.05). The most expensive patients had index fractures of the hip, multiple sites and femur (incremental costs of $US25 519, $US20 137 and $US19 403, respectively). Patients with NV non-hip (NVNH) fractures had incremental healthcare costs of $US7868 per patient ($US16 704 vs $US8836; p < 0.05). Aggregate annual incremental healthcare costs of NVNH patients in the Medicare research sample (n = 35 933) were $US282.7 million compared with $US204.1 million for hip fracture patients (n = 7997). Among the privately insured, mean incremental healthcare costs per NV fracture patient were $US5961 ($US11 636 vs $US5675; p < 0.05). The most expensive patients had index fractures of the hip, multiple sites and pelvis (incremental costs of $US13 801, $US9642 and $US8164, respectively). Annual incremental healthcare costs per NVNH patient were $US5381 ($US11 090 vs $US5709; p < 0.05). Aggregate annual incremental healthcare costs of NVNH patients in the privately insured sample (n = 4478) were $US24.1 million compared with $US3.5 million for hip fracture patients (n = 255). Mean incremental work loss costs per NV fracture employee were $US1956 ($US4349 vs $US2393; p < 0.05). Among patients with available disability data, work loss accounted for 29.5% of total costs per NV fracture employee. The cost burden of NV fracture patients to payers is substantial. Although hip fracture patients were more costly per patient in both Medicare and privately insured samples, NVNH fracture patients still had substantial incremental costs. Because NVNH patients accounted for a larger proportion of the fracture population, they were associated with greater aggregate incremental healthcare costs than hip fracture patients.

Relationship between adherence level to statins, clinical issues and health-care costs in real-life clinical setting

OBJECTIVE

Statins have been shown to reduce the risk of major cardiovascular disease. We recognize that there is a major gap between the use of statins in actual practice and treatment guidelines for dyslipidemia. Low adherence to statins may have a significant impact on clinical issues and health-care costs. The objective is to evaluate the impact of low adherence to statins on clinical issues and direct health-care costs.

METHODS

A cohort of 55,134 patients newly treated with statins was reconstructed from the Régie de l'Assurance Maladie du Québec and Med-Echo databases. Subjects included were aged between 45 and 85, initially free of cardiovascular disease, newly treated with statins between 1999 and 2002, and followed-up for a minimum of 3 years. Adherence to statins was measured in terms of the proportion of days' supply of medication dispensed over a defined period, and categorized as >or=80% or <80%. The adjusted odds ratio (OR) of cardiovascular events between the two adherence groups was estimated using a polytomous logistic analysis. The mean costs of direct health-care services were evaluated. A two-part model was applied for hospitalization costs.

RESULTS

The mean high adherence level to statins was around to 96% during follow-up; and this value was at 42% for the low adherence level. The patients with low adherence to statins were more likely to have coronary artery disease (OR 1.07; 95% confidence interval [CI], 1.01-1.13), cerebrovascular disease (OR 1.13; 95% CI 1.03-1.25), and chronic heart failure within 3-year period of follow-up (OR 1.13; 95% CI 1.01-1.26). Low adherence to statins was also associated with an increased risk of hospitalization by 4% (OR 1.04; 95% CI 1.01-1.09). Among patients who were hospitalized, low adherence to statins was significantly associated with increase of hospitalization costs by approximately $1060/patient for a 3-year period.

CONCLUSION

Low adherence to statins was correlated with a higher risk of cardiovascular disease, hospitalization rate, and hospitalization costs. An increased level of adherence to statins agents should provide a better health status for individuals and a net economic gain.

Health economic assessment: a methodological primer

This review article aims to provide an introduction to the methodology of health economic assessment of a health technology. Attention is paid to defining the fundamental concepts and terms that are relevant to health economic assessments. The article describes the methodology underlying a cost study (identification, measurement and valuation of resource use, calculation of costs), an economic evaluation (type of economic evaluation, the cost-effectiveness plane, trial- and model-based economic evaluation, discounting, sensitivity analysis, incremental analysis), and a budget impact analysis. Key references are provided for those readers who wish a more advanced understanding of health economic assessments.

Comparison of direct health care costs related to the pharmacological treatment of osteoporosis and to the management of osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate: a population-based study

This population-based study aimed to compare direct health care costs related to the pharmacological treatment of osteoporosis and to the management of osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate. During a 2-year follow-up period, compared to those with medication possession ratio (MPR) > or = 80%, women with MPR < 80% incurred significantly higher physician care costs and hospital care costs.

INTRODUCTION

This study aimed to compare direct health care costs related to the treatment of osteoporosis and osteoporotic fractures among compliant and noncompliant users of alendronate and risedronate.

METHODS

A cohort of 15,027 women having initiated alendronate or risedronate was identified. MPR and direct health care costs (physician care, hospital care, drugs) were assessed during a 2-year period. Regression models were used to estimate mean predicted cost for compliant (MPR > or = 80%) and noncompliant (MPR < 80%) women.

RESULTS

Mean predicted physician care cost (in Canadian dollars) was $51 among women with MPR < 80% and $34 among those with MPR > or = 80%: mean difference $17, 95% confidence interval (CI) $2-22. Mean predicted hospital care cost was $568 among women with MPR < 80% and $379 among those with MPR > or = 80%: mean difference $189, 95% CI $56-320. Mean predicted drug cost was $439 among women with MPR < 80% and $1,068 among those with MPR > or = 80%: mean difference $-639, 95% CI $-649 to -629.

CONCLUSION

Compared to compliant women, noncompliant women incurred significantly higher physician care and hospital care costs. Due to lower drug costs, total direct health care costs were lower among noncompliant women.

Inventory of data sources for estimating health care costs in the United States

OBJECTIVE

To develop an inventory of data sources for estimating health care costs in the United States and provide information to aid researchers in identifying appropriate data sources for their specific research questions.

METHODS

We identified data sources for estimating health care costs using 3 approaches: (1) a review of the 18 articles included in this supplement, (2) an evaluation of websites of federal government agencies, non profit foundations, and related societies that support health care research or provide health care services, and (3) a systematic review of the recently published literature. Descriptive information was abstracted from each data source, including sponsor, website, lowest level of data aggregation, type of data source, population included, cross-sectional or longitudinal data capture, source of diagnosis information, and cost of obtaining the data source. Details about the cost elements available in each data source were also abstracted.

RESULTS

We identified 88 data sources that can be used to estimate health care costs in the United States. Most data sources were sponsored by government agencies, national or nationally representative, and cross-sectional. About 40% were surveys, followed by administrative or linked administrative data, fee or cost schedules, discharges, and other types of data. Diagnosis information was available in most data sources through procedure or diagnosis codes, self-report, registry, or chart review. Cost elements included inpatient hospitalizations (42.0%), physician and other outpatient services (45.5%), outpatient pharmacy or laboratory (28.4%), out-of-pocket (22.7%), patient time and other direct nonmedical costs (35.2%), and wages (13.6%). About half were freely available for downloading or available for a nominal fee, and the cost of obtaining the remaining data sources varied by the scope of the project.

CONCLUSIONS

Available data sources vary in population included, type of data source, scope, and accessibility, and have different strengths and weaknesses for specific research questions.

Challenges in building disease-based national health accounts

BACKGROUND

Measuring spending on diseases is critical to assessing the value of medical care.

OBJECTIVE

To review the current state of cost of illness estimation methods, identifying their strengths, limitations, and uses. We briefly describe the current National Health Expenditure Accounts, and then go on to discuss the addition of cost of illness estimation to the National Health Expenditure Accounts.

CONCLUSION

Recommendations are made for future research aimed at identifying the best methods for developing and using disease-based national health accounts to optimize the information available to policy makers as they struggle with difficult resource allocation decisions.

Economic productivity by age and sex: 2007 estimates for the United States

BACKGROUND

Human capital estimates of labor productivity are often used to estimate the economic impact of diseases and injuries that cause incapacitation or death.

OBJECTIVES

Estimates of average hourly, annual, and lifetime economic productivity, both market and household, were calculated in 2007 US dollars for 5-year age groups for men, women, and both sexes in the United States.

RESEARCH DESIGN

Data from the American Time Use Survey were used to estimate hours of paid work and household services and hourly and annual earnings and household productivity. Present values of discounted lifetime earnings were calculated for each age group using the 2004 US life tables and a discount rate of 3% per year and assuming future productivity growth of 1% per year.

SUBJECTS

The estimates of hours and productivity were calculated using the time diaries of 72,922 persons included in the American Time Use Survey for the years 2003 to 2007.

RESULTS

The present value of lifetime productivity is approximately $1.2 million in 2007 dollars for children under 5 years of age. For adults in their 20s and 30s, it is approximately $1.6 million and then it declines with increasing age. Productivity estimates are higher for males than for females, more for market productivity than for total productivity.

CONCLUSIONS

Changes in hours of paid employment and household services can affect economic productivity by age and sex. This is the first publication to include estimates of household services based on contemporary time use data for the US population.

A multi-center survey of childhood asthma in Turke--I: the cost and its determinants

Successful management of childhood asthma requires a thorough idea of the economic impact of asthma and its determinants, as policy makers and physicians inevitably influence the outcome. The aim of this study was to define the cost of childhood asthma in Turkey and its determinants. In April 2006, a multi-center, national study was performed where data regarding cost and control levels were collected. Asthmatic children (6-18 yr) with at least a 1-yr follow-up seen during a 1-month period with scheduled or unscheduled visits were included. The survey included a questionnaire-guided interview and retrospective evaluation of files. Cost and its determinants during the last year were analyzed. A total of 618 children from 12 asthma centers were surveyed. The total annual cost of childhood asthma was US$1597.4 +/- 236.2 and there was a significant variation in costs between study centers (p < 0.05). Frequent physician visits [odds ratio (95% confidence intervals)] [2.3 (1.6-3.4)], hospitalization [1.9 (1.1-3.3)], asthma severity [1.6 (1.1-2.8)], and school absenteeism due to asthma [1.5 (1.1-2.1)] were major predictors of total annual costs (p < 0.05 for each). The comparable cost of asthma among Turkish children with that reported in developed countries suggests that interventions to decrease the economic burden of pediatric asthma should focus on the cost-effectiveness of anti-allergic household measures and on improving the control levels of asthma.

Cost of illness of glaucoma: a critical and systematic review

Cost-of-illness studies determine the total financial burden of a disease by considering direct and indirect costs, including medication, diagnostics and surgery. Studies of resource use and costs associated with primary open-angle glaucoma have used varying methodologies. Most have focused on consumption of healthcare resources at various stages of disease to anticipate costs. The direct costs associated with the disease often continue to increase as glaucoma progresses from the earliest to most advanced stages. Determinations of the costs associated with glaucoma progression and prevention should also incorporate the chance of patient non-compliance with treatment. Since glaucoma severity most often correlates with increased costs, minimizing or halting visual field loss and increasing patient treatment compliance may all contribute to a reduction in the overall economic burden of glaucoma.

The costs of treating breast cancer in the US: a synthesis of published evidence

Published estimates for the treatment costs of breast cancer vary widely in methodology, perspective, patient populations and time horizon. We systematically summarized and analysed the published literature on per-patient costs of breast cancer, and highlight the perspectives, populations studied, time horizons and future directions for cost studies in breast cancer. This review included 29 US cost-of-illness studies for breast cancer. The estimates of lifetime per-patient costs of breast cancer ranged from $US20 000 to $US100 000. Payer perspectives were popular, while disease stages I and II were emphasized. The costs of initial and terminal therapy were greater than continuing care on a per-unit time basis, but continuing care accounts for the largest share of lifetime cost due to the relatively long survival of breast cancer patients. Costs of different surgeries were relatively similar (breast-conserving surgery vs mastectomy) but, all else equal, significant costs ($US23 000-31 000) were observed for patients who received adjuvant chemotherapy compared with those who did not. Multiple studies confirmed that costs increased with increased stage of disease and costs decreased with increased age of diagnosis. The question remains whether or not lower costs for elderly patients are associated with lower quality of care. The patient, employer and societal perspectives were rarely presented. Experts in the field have recommended the societal perspective for US-based cost-effectiveness analyses. Most lifetime cost estimates were likely an underestimate for today's lifetime cost of treating breast cancer because of changes in practice patterns and improved survival. Further societal-based cost studies that differentiate costs by stage, age and treatment time (initial, continuing and terminal), and include the latest practice patterns would be valuable toward informing US-based cost-effectiveness studies for preventive as well as breast cancer treatment interventions.

Hospital costs associated with pediatric burn injury

Modern burn care is a resource intensive endeavor requiring specialized equipment, personnel, and facilities in order to provide optimum care. The costs associated with burn injury to both patients and society as a whole can be multifaceted and large. The purpose of this study was to evaluate the association between hospital costs, patient characteristics, and injury factors in a cohort of pediatric patients admitted to a regional burn center. We performed a review of the hospital charges accrued by pediatric patients (age <16 years) admitted to our burn center from 1994 to 2004 and explored the relationship between baseline patient, injury and hospital course characteristics and total costs. Hospital charges were converted to 2005 dollar costs using an inflation index and a cost to charge ratio. Univariate and multivariate regressions were performed to identify the factors most significantly associated with cost. In addition, we performed a subset cost analysis for patients with burns more than 20% TBSA. A total of 1443 pediatric patients (age <16) were admitted to our burn center during the study period. The overall mean hospital cost in 2005 dollars was dollars 9026 (SD = dollars 25,483; median = dollars 2138). Area of full thickness burn was the only patient or injury factor significantly associated with greater hospital costs (P < .05) on multivariate analysis. No single anatomic area was associated with increased hospital costs when adjusted for total overall burn size. Injury severity was the most significant factor impacting index hospitalization costs following pediatric burn injury. Further studies defining the long-term societal costs impact of burn injury are needed as are studies that evaluate the impact of burn injury on quality of life.

Contemporary outcomes research: tools of the trade

Outcomes are, simply put, why a surgeon comes to work each day. For decades, surgeons have insisted on a regular self-examination of outcomes to ensure the optimal treatment of our patients. Clinical research in pediatric surgery has largely subsisted on outcome analysis as it relates to the rudimentary end-result of an operation, utilizing variables such as mortality, operative time, specific complication rates, and hospital length of stay to name a few. Recently, outcomes research has become a more complex endeavor. This issue of Seminars in Pediatric Surgery addresses a wide array of these newfound complexities in contemporary outcomes research. The purpose of this review is to assist the pediatric surgeon in understanding the tools that are used in contemporary outcomes research and to be able to use this information to ask new questions of our patients and ourselves as we continue to strive for excellence in caring for sick infants and children.

Cost of illness: an international comparison. Australia, Canada, France, Germany and The Netherlands

OBJECTIVES

To assess international comparability of general cost of illness (COI) studies and to examine the extent to which COI estimates differ and why.

METHODS

Five general COI studies were examined. COI estimates were classified by health provider using the system of health accounts (SHA). Provider groups fully included in all studies and matching SHA estimates were selected to create a common data set. In order to explain cost differences descriptive analyses were carried out on a number of determinants.

RESULTS

In general similar COI patterns emerged for these countries, despite their health care system differences. In addition to these similarities, certain significant disease-specific differences were found. Comparisons of nursing and residential care expenditure by disease showed major variation. Epidemiological explanations of differences were hardly found, whereas demographic differences were influential. Significant treatment variation appeared from hospital data.

CONCLUSIONS

A systematic analysis of COI data from different countries may assist in comparing health expenditure internationally. All cost data dimensions shed greater light on the effects of health care system differences within various aspects of health care. Still, the study's objectives can only be reached by a further improvement of the SHA, by international use of the SHA in COI studies and by a standardized methodology.

Use of econometric models to estimate expenditure shares

OBJECTIVE

To investigate the use of regression models to calculate disease-specific shares of medical expenditures.

DATA SOURCES/STUDY SETTING

Medical Expenditure Panel Survey (MEPS), 2000-2003.

STUDY DESIGN

Theoretical investigation and secondary data analysis.

DATA COLLECTION/EXTRACTION METHODS

Condition files used to define the presence of 10 medical conditions.

PRINCIPAL FINDINGS

Incremental effects of conditions on expenditures, expressed as a fraction of total expenditures, cannot generally be interpreted as shares. When the presence of one condition increases treatment costs for another condition, summing condition-specific shares leads to double-counting of expenditures.

CONCLUSIONS

Condition-specific shares generated from multiplicative models should not be summed. We provide an algorithm that allows estimates based on these models to be interpreted as shares and summed across conditions.

Infantile gastroenteritis in the community: a cost-of-illness study

Rotavirus infections are the main cause of gastroenteritis in infants and children and it is expected that by the age of 5 years, nearly every child will have experienced at least one episode of rotavirus gastroenteritis. While severe cases are hospitalized, milder disease is either treated at home or by the GP, and as such the true prevalence of rotavirus infection in the community, and the burden of disease, is unknown. This paper reports the results of a cost-of-illness study which was conducted alongside a structured community surveillance study. Forty-eight percent of our sample was found to have rotavirus acute gastroenteritis; and the average total cost of a child presenting with rotavirus gastroenteritis ranged between pound sterling 59 and pound sterling 143 per episode, depending on the perspective. Given the prevalence and severity of the disease, the estimated burden of rotavirus gastroenteritis to society is pound sterling 11.5 million per year.

The economic burden of chronic cardiovascular disease for major insurers

Accounting models provide less precise estimates of disease burden than do econometric models. The authors seek to improve these estimates for cardiovascular disease using a nationally representative survey and econometric modeling to isolate the proportion of medical expenditures attributable to four chronic cardiovascular diseases: stroke, hypertension, congestive heart failure, and other heart diseases. Approximately 17% of all medical expenditures, or $149 billion annually, and nearly 30% of Medicare expenditures are attributable to these diseases. Of the four diseases, hypertension accounts for the largest share of prescription expenditures across payers and the largest share of all Medicaid expenditures. The large number of people with cardiovascular disease who are eligible for both Medicare and Medicaid could lead to large shifts in the burden to these payers as prescription drug coverage is included in Medicare. A societal perspective is important when describing the economic burden of cardiovascular disease.

Methods for determining cost-benefit ratios for pharmaceuticals in Germany

The aim of this methodological paper is to summarize evidence on how to implement cost-benefit assessment according to the new German legislative framework (Competition Enhancement Act). Given the complexity of existing health policy frameworks within industrialised countries in adapting health economics in their respective regulatory scheme, no clear international scientific consensus on which health economic methods should be chosen for assessment can be determined. Nevertheless, a broad consensus on the internal properties of methods itself can be found. Based on these common international standards in methodology, this work provides a minimum catalogue of methods and criteria that meet legal and local German requirements with regard to specific factors of its health care system. Aside from categorising clearly defined standards (e.g., study forms, cost and benefit categories) the suggested catalogue specifies some intensively debated areas in Germany (e.g., the QALY, modelling, the perspective used in the assessment). After the proposition of certain methods the paper leads to a first recommendation of a detailed assessment-process itself specific for the German way in implementing cost-benefit ratios within regulatory decision making in Germany.