Clinical outcomes and cost-effectiveness of strategies for managing people at high risk for diabetes

Background: Lifestyle modification can forestall diabetes in high-risk people, but the long-term cost-effectiveness is uncertain. Objective: To estimate the effects of the lifestyle modification program used in the Diabetes Prevention Program (DPP) on health and economic outcomes. Design: Cost-effectiveness analysis using the Archimedes model. Data Sources: Published basic and epidemiologic studies, clinical trials, and Kaiser Permanente administrative data. Target Population: Adults at high risk for diabetes (body mass index > 24 kg/m(2), fasting plasma glucose level of 5.2725 to 6.9375 mmol/L [95 to 125 mg/dL] 2-hour glucose tolerance test result of 7.77 to 11.0445 mmol/L [140 to 199 mg/dL]). Time Horizon: 5 to 30 years. Perspective: Patient, health plan, and societal. Interventions: No prevention, DPP's lifestyle modification program, lifestyle modification begun after a person develops diabetes, and metformin. Measurements: Diagnosis and complications of diabetes. Results of Base-Case Analysis: Compared with no prevention program, the DPP lifestyle program would reduce a high-risk person's 30-year chances of getting diabetes from about 72% to 61%, the chances of a serious complication from about 38% to 30%, and the chances of dying of a complication of diabetes from about 13.5% to 11.2%. Metformin would deliver about one third the long-term health benefits achievable by immediate lifestyle modification. Compared with not implementing any prevention program, the expected 30-year cost/quality-adjusted life-year (QALY) of the DIPP lifestyle intervention from the health plan's perspective would be about $143 000. From a societal perspective, the cost/QALY of the lifestyle intervention compared with doing nothing would be about $62 600. Either using metformin or delaying the lifestyle intervention until after a person develops diabetes would be more cost-effective, costing about $35 400 or $24 500 per QALY gained, respectively, compared with no program. Compared with delaying the lifestyle program until after diabetes is diagnosed, the marginal cost-effectiveness of beginning the DPP lifestyle program immediately would be about $201 800. Results of Sensitivity Analysis: Variability and uncertainty deriving from the structure of the model were tested by comparing the model's results with the results of real clinical trials of diabetes and its complications. The most critical element of uncertainty is the effectiveness of the lifestyle program, as expressed by the 95% CI of the DPP study. The most important potentially controllable factor is the cost of the lifestyle program. Compared with no program, lifestyle modification for high-risk people can be made cost-saving over 30 years if the annual cost of the intervention can be reduced to about $100. Limitations: Results depend on the accuracy of the model. Conclusions: Lifestyle modification is likely to have important effects on the morbidity and mortality of diabetes and should be recommended to all high-risk people. The program used in the DPP study may be too expensive for health plans or a national program to implement. Less expensive methods are needed to achieve the degree of weight loss seen in the DPP.