Table 6.

Health economic analyses based on the Diabetes Prevention Program/Diabetes Prevention Program Outcome Study

Country	Purpose of the study	Summary of main findings
US [81]	Lifetime cost-utility of DPP interventions	ILI and metformin delayed diabetes onset by 11 and 3 years, respectively, and increased life expectancy by 0.5 and 2 years, respectively, due to projected lower incidence of diabetic complications. Cost per QALY vs. placebo was $1100 dollars (ILI) and $31,300 (metformin) for health service perspective, and $8800 dollars (ILI) and $29,900 (metformin) for societal perspective. ILI dominated metformin
US [157]	Costs of interventions within the randomised phase of the DPP	3-year cost per subject of metformin relative to placebo:  Health system perspective: $2191 (metformin); $2269 (ILI)  Societal perspective: $2412 (metformin); $3540 (ILI) Costs inside the trial were lower for placebo vs. other interventions and costs outside the trial were highest for placebo
US [158]	Within-trial cost effectiveness from health system and societal perspectives	Health system perspective: cost of preventing one case of diabetes vs. placebo—$15,655 (ILI) and $31,338 (metformin); costs per QALY–$31,512 (ILI) and $99,611 (metformin) Societal perspective: cost of preventing one case of diabetes vs. placebo—$24,426 (ILI) and $34,489 (metformin); costs per QALY—$51,582 (ILI) and $99,171 (metformin)
US [159]	Ten-year evaluation of the cost effectiveness of DPP interventions from the DPP and DPPOS	Total direct medical costs were greater for ILI ($29,164) than metformin ($27,915) or placebo ($28,236). Discounted ICER (health system perspective) was $10,037 for ILI vs. placebo and $13,420 for ILI vs. metformin. Metformin was cost saving vs. placebo
US [160]	Cost effectiveness of DPP interventions	ILI reduced 30-year diabetes risk in high-risk subjects from 72 to 61 % in an Archimedes model; metformin provided approximately one-third as much long-term benefit as immediate ILI
Australia, France, Germany, Switzerland, UK [161]	Markov modelling of long-term implications of DPP interventions	ILI and metformin were cost saving vs. placebo in all countries except the UK (+€1021 for ILI and +€378 for metformin at 2002 values). Improvements in life expectancy were 0.35 years for metformin and 0.90 years for ILI
Australia [162]	Markov model of DPP interventions in Australia	Lifetime incremental direct costs/subject vs. control—$1217 (metformin), and a savings of $289 (ILI). Incremental cost per QALY was $10,142 for metformin. Probability of willingness-to-pay at $50,000 was 78 % (metformin) and 100 % (ILI)
Germany [163]	Cost effectiveness of ‘real world’ diabetes prevention according to DPP interventions	Metformin and ILI would prevent 42 and 184 cases of diabetes, respectively, of a total number of 14,908 cases of diabetes in a population of 72,500 over 3 years. Costs for ILI were €856,507 (health system perspective) and €4,961,340 (society perspective); costs for metformin were €797,539 (health system perspective) and €1,335,204 (society perspective). ICERs per case prevented for ILI vs. no intervention were €4664 (health system perspective) and €27,015 (societal perspective); corresponding figures for metformin were not provided

DPP Diabetes Prevention Program, DPPOS Diabetes Prevention Program Outcomes Study, ICER incremental cost-effectiveness ratio, ILI intensive lifestyle intervention, QALY quality-adjusted life-year