A Review and Analysis of Economic Models of Prevention Benefits. A Review and Analysis of Economic Models of Prevention Benefits : Table 8


: Table 8

Abstracted informationTrogden et al. 2009 A return-on-investment simulation model of workplace obesity interventionsWang et al. 2008 Cost-effectiveness of a school-based obesity prevention programFinkelstein et al. 2008 The lifetime medical cost burden of overweight and obesity: implications for obesity preventionHaynes et al. 2010 Long-term cost-effectiveness of weight management in primary careSassi et al. 2009 OECD Health Working Paper No. 48 Improving lifestyles, tackling obesity: the health and economic impact of prevention strategiesCarter et al. 2009 Assessing cost-effectiveness in obesity (ACE-Obesity): an overview of the ACE approach, economic methods and cost results
Framework (BCA, CEA, etc.)ROICEABurden of diseaseCEACEACEA (Assessing Cost-Effectiveness {ACE} in Obesity approach)
PerspectiveWork organizationSocietalSocietalPayerSocietalSocietal (Providers, Private sector, Non-health sectors)
Target populationAmericansAmericansAmericansBritishAny country (can be adapted to simulate a specific country)Australians
Study population (epidemiological)1,000 employees representative of the working US populationEighteen elementary schools in Augusta, GA; a total of 601 subjectsNationally representative civilian noninstitutionalized populationBroad representative of UK population based on age, gender, BMI, etc.Europeans (intervention by country)Children and adolescents (aged 5-19) - target age/condition groups varied according to intervention
Study population (economic)Same as aboveSame as abovePerspective of a 20 and 65 year old1906 patientsSame as aboveAustralian population of children and adolescents in year 2001 followed over time
Intervention(s)Worksite strategies (based on CDC Community Guide); Weight Watchers; prescription drug coverage; workplace redesign"Fitogenic" after-school environment that encouraged moderate-to-vigorous physical activity (MVPA) and health snacks while discouraging sedentary behaviorN/ACounterweight Program for weight management delivered in Family Practice and other settings by practice nurses and health care workers, with initial guidance and facilitation by 'weight management advisers'Multiple interventions: mass media campaigns, school-based interventions, worksite interventions, fiscal measures, regulation of food advertising to children, compulsory food labeled, physician/dietician counselingModel is designed to select among specific interventions. Selection criteria: (1) relevance to current policy decision making; (2) availability of evidence to support meaningful analysis (3) potential impact on addressing the problem (4) ability to specify in clear concrete terms (5) inclusion of a mix of intervention (broad & narrow), and across a range of settings (6) consideration of program logic
Comparator(s)No interventionNo interventionN/ANo programNo interventionCurrent practice (assumed to be 'no intervention’)
Data sourcesCDC 2005 Behavioral Risk Factor Surveillance System, 2005 Current Population Survey, 2005 National Health Interview Survey, 2001-2003 Medical Expenditure Panel Survey, 2003-2004National Center for Education Statistics (NCES)Medical Expenditure Panel Survey 2001-2004; NHIS 1986-2000; National Death Index 1986-2002Counterweight Program evaluation, Office of National Statistics, Health Survey for England, Ara et al. (2005), O'Leary et al. (2004)WHO, NHANES, HSE, Tan Torres et al. (2003)Country-specific data where possible, health system costs and disease incidence/prevalence patterns
Valuation of health benefits ($, QALYs, LYS, cases averted)Cost-savingsReduction in percent body fat (%BF)N/Aquality-adjusted life years (QALYs)Disability-adjusted life years (DALYs)Disability-adjusted life years (DALYs), cost offsets (savings in future health sector expenditure: non-health prevention e.g. safer transport systems, personal activities that maintain/improve health, benefits reflected not in health, time)
CostsMedical, absenteeismPersonnel (coordinator salary and payment of program instructors), instructor training (room, food, supplies, compensation), transportation (school buses, administrators), materials (cost of sports equipment, handbooks, activity books, paper, printing, T-shirtLifetime medical expenditures (no further specification)Diabetes, coronary heart disease, colon cancer, Counterweight programIntervention at the patient level: medicines, visits, hospital stays, individual health education message. Program level: administration, publicity, training, delivery of suppliesProduction losses/gains, time, intervention (teachers, materials, equipment)   Valuation of costs: measured in real terms for reference year, CPI to adjust for inflation (not health inflator, since some are outside of health sector)
Time horizonMulti-year (outcomes is in units of annual cost reduction)1 yearLifetimeLifetime100 yearsLifetime or age 100 years
Discount rate (annual)Costs and benefits 3%N/SCosts 3%Costs and benefits 3.5%Costs and benefits 3%Costs and benefits 3%
Model design (static/dynamic)Dynamic (No further specification)Static (no further specification)Dynamic (simple linear regression)Dynamic (no further specification)Dynamic (microsimulation, stochastic/probabilistic sensitivity analysis)Dynamic (e.g. disease-specific rates for each 5-year age group), Monte Carlo simulation
Sensitivity analysis (parameters)N/AOne-way: per capita usual after-school care costsOne-way not specified.   Multi-way: mortality by BMI classOne-way: mean weight loss from program, time taken to regain any weight lost from program, underlying background weight gain trendOne or multi-way not specified: effectiveness, coverage, socioeconomic statusOne or multi-way not specified: results reflecting explicitly the uncertainty of  cost, process, outcome and value estimates (usually economic and epidemiological inputs)
Value of informationN/SN/SNoNoN/SNo
Generalizability/ scalability of findings        
Distributional or equity analysisN/SN/SN/SN/SSensitivity analysis of socioeconomic status shows less well-off enjoy larger life-year gains. Gini coefficient: all interventions have a favorable but small effect on health equityConsidered in assessment of degree of confidence in CE ratios or broader resource allocation issues
ResultsAcross all over-weight and obese employees, 5% weight loss would result in a reduction in total annual costs (medical plus absenteeism) of $90 per personIntervention costs were $558/student or $956/student who attended ≥40% of the sessions. Costs net of usual after-school care costs per participating student were $317/student. Students attending ≥40% of the intervention reduced body fat by 0.76% (95% CI: -1.42 to -0.09%) underweight (BMI: <18.5), low/normal(BMI: 18.5–19.9), normal (BMI: 20–24.9, omitted in specification  for reference), overweight (BMI: 25–29.9), obese I (BMI: 30–34.9), obese II/III combined (BMI: >35)   With the exception of white women, the lifetime costs of overweight are around zero. For 20-year-old overweight white women, these costs are estimated at $8,120, with only 11% occurring beyond age 65. From the perspective of a 65 year old, the costs of overweight are $4,560.For 20-year-old obese I adults, lifetime costs range from$5,340 for black women to $21,550 for white women.   For 20 year olds in the obese II/III class, black men have the lowest lifetime cost estimates, $14,580, and white women again have the highest lifetime cost estimates, $29,460. For men, the costs of obese II/III are similar to those of obese I. From the perspective of an obese 20 year old, the percentage of costs occurring after age 65 ranges from 3% for obese II/III black women to28% for obese I black men.   From the perspective of a 65 year old, lifetime costs of obese I range from $4,660 (black women) to $19,270 (black men). For obese II/III, these estimates range from $7,590 (black women) to $25,300 (white women). From this perspective, lifetime costs are higher for the obese II/III class than for those who are obese I.Even assuming dropouts⁄ non-attenders at 12 months (55%) lost no weight and gained at the background rate, Counterweight was ‘dominant’ (cost-saving) under ‘base-case scenario’, where 12-month achieved weight loss was entirely regained over the next 2 years, returning to the expected background weight gain of 1 kg ⁄ year.   The ICER was £2017/QALY  where background weight gain was limited to 0.5 kg ⁄ year, and £2,651 at 0.3 kg ⁄ year.   Under a ‘best-case scenario', where weights of 12-month-attenders were assumed thereafter to rise at the background rate, 4 kg below non-intervention trajectory (very close to the observed weight change), Counterweight remained ‘dominant’ with background weight gains1 kg, 0.5 kg or 0.3 kg ⁄ year.Most interventions have cost-effectiveness ratios between 0 and $50,000 with two interventions, namely fiscal measures and food advertising self-regulation, generating savings.The intervention costs varied considerably, both in absolute terms (from cost saving [6 interventions] to in excess of AUD50m per annum) and when expressed as a 'cost per child' estimate (from <AUD1.0 [reduction of TV advertising of high fat foods/high sugar drinks] to AUD31,553 [laparoscopic adjustable gastric banding for morbidly obese adolescents]). High costs per child reflected cost structure, target population and/or underutilization.
LimitationsAvoid future obesity-attributable costs; does not account for worker's compensation, disability and insurance costs. and reduced productivity; assumes a stable cohort of employees (higher raters of employee turnovers are likely to realize smaller gains from interventions; in reality, not all firms bear the total costsPublic health significance of %BF is unknown, because studies have tried to define obesity in children by %BF rather than BMI percentiles; intermediary outcome measured, instead of final outcome in terms of health status indicatorData limitations for estimation and exclusion of other obesity effects, such as use of nursing home care, absenteeism, presenteeism, disability, worker's compensation, and decreased quality of lifeData limitations on background trend in weight gain - although sensitivity analysis shows still cost-effective despite more conservative estimatesCombinations of  input data from heterogeneous sources; simplification of relationships among risk factors in mathematical model; assumption of uniform effectiveness across all subpopulation groups (affects distributional analysis results)Assessment of issues that either influence the degree of confidence that can be placed in the CE ratios, or broader issues that need to be taken into account in decision-making about resource allocation: equity, strength of evidence, feasibility of implementation, acceptability to stakeholders, sustainability, and potential for side effects   Cost offset may be overestimated, since they are based on the mean reduction in BMI; variability in salary structure, health systems, unit costs, implementation method, population size and structure between countries