Health utilities
Every year after randomization, quality of life was better for lifestyle than for metformin or placebo (Supplementary Table 3). Across treatment groups, quality of life was worse among participants who developed diabetes (Supplementary Table 3). Since more placebo participants developed diabetes, the cumulative, undiscounted, per participant quality of well-being score gained over 10 years was greatest for lifestyle (6.89), intermediate for metformin (6.79), and least for placebo (6.74)
(Fig. 1D).