Table 4.

Associations of metformin use with risk of all-cause mortality, stratified by stage at diagnosis in who were metformin naïve at the time of PDAC diagnosis, using the time-varying Cox model.

Metformin useDeaths/totalMedian survival (95% CI)HR (95% CI)aPPheterogeneity
Patients with localized/locally advanced disease
  Nonuserb318/3347.7 (6.2–8.8)Ref.
  User45/6432.4 (23.7–55.5)1.02 (0.73–1.44)0.90
 Non-Hispanic whites
  Nonuserb242/2558.4 (6.8–9.7)Ref.
  User40/5632.4 (23.9–55.5)1.02 (0.70–1.48)0.91
 African Americans
  Nonuserb76/795.3 (3.9–7.3)Ref.
  User5/823.0 (1.6–32.1)1.51 (0.51–4.49)0.46
Patients with metastatic disease
  Nonuserb500/5052.3 (1.9–2.6)Ref.
  User43/466.3 (4.6–8.8)0.82 (0.59–1.55)0.25
 Non-Hispanic whites
  Nonuserb377/3812.3 (1.9–2.7)Ref.
  User29/316.4 (4.3–8.9)0.67 (0.44–1.01)0.06
 African Americans
  Nonuserb123/1242.3 (1.7–2.6)Ref.
  User14/155.8 (1.8–9.2)1.39 (0.77–2.53)0.28
  • 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.