Abstract
OBJECTIVE: The study objective was to evaluate the cost-effectiveness of alternative fasting plasma glucose (FPG) thresholds to identify adults at high risk for type 2 diabetes for diabetes preventive intervention. RESEARCH DESIGN AND METHODS: We used a validated simulation model to examine the change in lifetime quality-adjusted life years (QALYs) and medical costs when the FPG threshold was progressively lowered in 5-mg/dL decrements from 120 to 90 mg/dL. The study sample includes nondiabetic adults aged ≥45 years in the United States using 2006-2010 data from the National Health and Nutrition Examination Survey. High-risk individuals were assumed to receive a lifestyle intervention, as that used in the Diabetes Prevention Program. We calculated cost per QALY by dividing the incremental cost by incremental QALY when lowering the threshold to the next consecutive level. Medical costs were assessed from a health care system perspective. We conducted univariate and probabilistic sensitivity analyses to assess the robustness of the results using different simulation scenarios and parameters. RESULTS: Progressively lowering the FPG threshold would monotonically increase QALYs, cost, and cost per QALY. Reducing (in 5-mg/dL decrements) the threshold from 120 to 90 mg/dL cost $30,100, $32,900, $42,300, $60,700, $81,800, and $115,800 per QALY gained, respectively. The costs per QALY gained were lower for all thresholds under a lower-cost and less-effective intervention scenario. CONCLUSIONS: Lowering the FPG threshold leads to a greater health benefit of diabetes prevention but reduces the cost-effectiveness. Using the conventional benchmark of $50,000 per QALY, a threshold of 105 mg/dL or higher would be cost effective. A lower threshold could be selected if the intervention cost could be lowered.