Table 2.

Associations of metformin use with risk of all-cause mortality in patients with PDAC with preexisting diabetes mellitus.

Time-varying Cox modelaConventional Cox modela
Metformin useDeaths/totalMedian survival (95% CI)HR (95% CI)PPheterogeneityHR (95% CI)PPheterogeneity
Overall0.610.9
 Nonuserb988/1,0193.7 (3.3–4.0)Ref.Ref.
 User2,623/2,7924.5 (4.2–4.8)1.05 (0.92–1.14)0.280.89 (0.83–0.98)0.01
Non-Hispanic whites
 Nonuserb746/7703.8 (3.3–4.3)Ref.Ref.
 User2,137/2,2684.5 (4.1–4.8)1.05 (0.96–1.14)0.280.90 (0.83–0.98)0.02
African Americans
 Nonuserb242/2493.4 (2.8–4.0)Ref.Ref.
 User486/5244.6 (3.4–5.4)1.01 (0.86–1.19)0.880.89 (0.76–1.05)0.17
  • aAdjusted for age (continuous), gender (male or female), BMI, year of diagnosis (2004 and prior, 2005–2008, 2009, and after), surgery (yes or no), smoke status (never, current, or previous), and stage (resectable, locally advanced, metastatic, or unknown).

  • bMetformin nonusers comprised individuals who were not taking just metformin. They could be taking other medications for diabetes.