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| Time to give nutrition interventions a higher profile: cost-effectiveness of 10 nutrition interventions |
| Dalziel K, Segal L |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. CRD summary The objective was to assess the cost-effectiveness of a range of nutrition interventions designed to reduce the risks for chronic disease. The authors concluded that all the interventions appeared to be cost-effective from a societal perspective. Overall, the methodology was adequate and both the methods and results were adequately presented. More details of the comparators should have been given, to assess if all the interventions were compared against the same benchmark. Type of economic evaluation Cost-effectiveness analysis, cost-utility analysis Study objective The objective was to assess the cost-effectiveness of a range of nutrition interventions designed to improve diet and reduce the risk of chronic disease. Interventions The study compared a range of nutrition interventions designed to reduce obesity and the risk of cardiovascular disease, diabetes, and cancer:
Mediterranean Diet - a one-hour session with a cardiologist and a dietician, where the patient was advised to follow a Mediterranean diet;
Reduced Fat Diet for IGT - a one-year programme of education, goals, and group sessions for patients with impaired glucose tolerance (IGT);
Intensive Life-style Change to Prevent Diabetes - diet advice and exercise, seven visits in one year and four after that;
Gutbusters Workplace - six weeks of small group sessions in the workplace consisting of education, tailored reports, weight loss guide, and behavioural change;
Nurse Counselling in GP - two sessions with a nurse at the primary care general practitioner (GP) setting;
Multi Media 2 fruit 5 veg Campaign - a three-week television advertising strategy for three years;
FFFF Media Campaign - a fighting fit, fighting fat seven-week media campaign consisting of a registration scheme including self-help guide and exercise vouchers; and
Oxcheck Nurse Checks in GP - primary care annual health checks conducted by nurses in the GP setting, with targets and follow up.
Two other interventions were identified for evaluation, but subsequently excluded due to poor effectiveness data. Location/setting Australia/primary and community care. Methods Analytical approach:The authors modelled the relationship between the reported changes in behaviour or clinical parameters and mortality and quality of life. For each intervention, a state transition Markov model was developed. The time horizon of the analysis was 20 years, except for the Reduced Fat Diet for IGT, which was five years. The authors reported that a societal perspective was adopted.
Effectiveness data:The effectiveness and clinical parameters were derived from a review of the literature. Medline, CINAHL and the Cochrane Database were searched and the bibliographies of included studies were hand-searched to identify further relevant studies. A professional advisory group in nutrition and disease burden guided the selection process. The broad inclusion criteria were: a clear description of the intervention, objective outcome measure, good scientific rigour (ideally a randomised controlled trial), health as the primary objective, and the appropriate length of follow-up. For each intervention, one representative study was used as the primary source of the effectiveness and cost data. The quality of these studies was appraised using standards set by the Centre for Reviews and Dissemination. The main effectiveness parameter for each model varied, as the primary source of effectiveness varied for each intervention. These included: increase in fruit and vegetable consumption, weight loss, deaths averted, and incidence of diabetes.
Monetary benefit and utility valuations:Quality of life estimates were derived from a number of published studies, which used the Australian quality of Life (AqoL), the Short Form (SF-36), the European Quality of life (EQ-5D), and time trade-off (TTO) instruments.
Measure of benefit:The measure of benefit was quality-adjusted life-years (QALYs) gained. The cost-effectiveness analysis was based purely on trial results, with ratios expressed as the cost per natural unit, such as the cost per additional serving of fruit.
Cost data:The resource use categories were not explicitly reported. The data were mainly derived from the studies selected for the effectiveness data. The unit costs were derived from Australian published sources, such as the Medicare Benefits Schedule. All costs were reported in 2003 Australian dollars (AUD). As they could be incurred over a long time period, future costs were discounted at an annual rate of 5%.
Analysis of uncertainty:The authors reported that extensive one-way sensitivity analyses were performed by varying the estimates of effect size, cost, utility, time horizon, and discount rate. Results The QALYs and costs were compared with the control group in each of the studies used for the main effectiveness and resource use data.
Compared with the control group, the additional mean QALY gains and mean incremental costs were: 0.77 QALYs and AUD 787 with Mediterranean Diet; 0.024 QALYs and AUD 241 with Reduced Fat Diet for IGT; 0.41 QALYs and AUD 769 with Intensive Life-style Change to Prevent Diabetes; 0.087 QALYs and AUD 917 with Nutrition Counselling in GP; 0.0045 QALYs and AUD 57 with Oxcheck Nurse Checks in GP; 0.0048 QALYs and AUD 0.20 with Multi Media 2 fruit 5 veg Campaign; 0.0546 QALYs and AUD 308 with FFFF Media Campaign; and 0.02 QALYs and AUD 356 with Gutbusters Workplace.
The costs and benefits were combined using an incremental cost-utility analysis (i.e. the additional cost per QALY gained), compared with the control group. This was: AUD 1,020 for Mediterranean Diet; AUD 10,000 for Reduced Fat Diet for IGT; AUD 1,880 for Intensive Life-style Change to Prevent Diabetes; AUD 10,600 for Nutrition Counselling in GP; AUD 12,600 for Oxcheck Nurse Checks in GP; AUD 46 for Multi Media 2 fruit 5 veg Campaign; AUD 5,600 for FFFF Media Campaign; and AUD 19,800 for Gutbusters Workplace.
The results of the sensitivity analyses showed that, when the effect size was varied sufficiently, the two multi-media campaigns were dominated (i.e. they were both more costly and less effective than the control). The authors reported that this reflected the poorer quality, and thus the greater uncertainty, in the results of these two trials. Authors' conclusions The authors concluded that all the nutrition interventions investigated appeared to be cost-effective from a societal perspective. CRD commentary Interventions:A literature review was undertaken to identify the potential interventions, ten were identified, but two were later rejected, and eight were included. All the interventions were clearly reported, but the details of the comparator in each of the selected studies were not provided. This means it was unclear whether the comparators were the same and whether they represented current practice.
Effectiveness/benefits:The effectiveness and clinical data were derived from a literature review. The authors provided adequate details of the sources used to identify potential studies and the inclusion criteria for each study. A professional expert panel was set up to guide this selection process. It is, therefore, unlikely that any major relevant study was omitted.
Costs:As the resource use information for each of the eight interventions was taken from each of the eight reports, few details of the resource use categories were given. The authors reported that a societal perspective was adopted, but no mention of indirect costs or productivity losses was made. As a result, it is not clear if these costs were analysed. The authors reported that the unit costs were derived from Australian published sources. The price year, time horizon and discount rate were all adequately reported.
Analysis and results:The costs and benefits were combined using a Markov model for each of the interventions. The uncertainty in each model was assessed using a series of one-way sensitivity analyses for a wide range of variables. However, a probabilistic sensitivity analysis was not performed and this is a more thorough way to evaluate the overall model uncertainty. Although the methods and results were generally well reported, the details of the comparators were not given. As a result, it is unclear if each of the eight interventions was compared against a similar benchmark and whether this represented current practice. The eight interventions were also not compared head-to-head to determine which was the most cost-effective.
Concluding remarks:Overall, the methodology was adequate and the methods and results were adequately presented. However, more details of the comparators should have been given to assess if all the interventions were compared against the same benchmark. Funding Supported by a grant from the Faculty of Business and Economics, Monash University. Bibliographic details Dalziel K, Segal L. Time to give nutrition interventions a higher profile: cost-effectiveness of 10 nutrition interventions. Health Promotion International 2007; 22(4): 271-283 Other publications of related interest Pavlovich WD, Waters H, Weller H, et al. Systematic review of literature on the cost-effectiveness of nutrition services. J Am Diet Assoc 2004;104:226-32.
Dalziel K, Segal L, de Lorgeril M. A Mediterranean diet is cost-effective in patients with previous myocardial infarction. J Nutr 2006;136:1879-85.
Dalziel K, Segal L, Elley CR. Cost utility analysis of physical activity counselling in general practice. Aust N Z J Public Health 2006;30:57-63. Indexing Status Subject indexing assigned by NLM MeSH Cost-Benefit Analysis; Counseling /economics /statistics & Diabetes Mellitus, Type 2 /economics /prevention & Female; Humans; Life Style; Male; Models, Economic; Nutrition Therapy /economics /methods /statistics & Quality-Adjusted Life Years; Risk Factors; control; numerical data; numerical data AccessionNumber 22007008333 Date bibliographic record published 15/04/2009 Date abstract record published 30/09/2009 |
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