Table 3.
Adjusted Analysis by Time-Varying Model and Conventional Cox Proportional Hazards Regression Analysis
| Metformin Use | Deaths/Total | Median Survival (95% CI)* | Time-Varying Model | Conventional Cox Model | ||
|---|---|---|---|---|---|---|
| HR (95% CI)† | P‡ | HR (95% CI)* | P‡ | |||
| Overall | .2989 | .1026 | ||||
| Never | 564/614 | 8.9 (8.0 to 9.6) | Ref | Ref | ||
| Ever | 311/366 | 9.9 (8.2 to 10.7) | 0.92 (0.79 to 1.08) | 0.88 (0.76 to 1.03) | ||
| Resectable | .2873 | .1113 | ||||
| Never | 153/187 | 19.4 (16.7 to 23.5) | Ref | Ref | ||
| Ever | 70/97 | 22.8 (18.6 to 30.9) | 0.84 (0.62 to 1.15) | 0.78 (0.57 to 1.06) | ||
| Locally advanced | .0284 | .0198 | ||||
| Never | 211/222 | 8.1 (6.9 to 9.5) | Ref | Ref | ||
| Ever | 111/132 | 10.2 (8.9 to 12.9) | 0.75 (0.58 to 0.97) | 0.74 (0.57 to 0.95) | ||
| Metastatic | .1732 | .3100 | ||||
| Never | 199/204 | 5.3 (4.6 to 6.1) | Ref | Ref | ||
| Ever | 130/137 | 4.9 (3.8 to 5.9) | 1.19 (0.93 to 1.54) | 1.14 (0.88 to 1.48) | ||
| Metformin naïve | .7692 | .8377 | ||||
| Never | 564/614 | 8.9 (8.0 to 9.6) | Ref | Ref | ||
| Ever | 72/85 | 10.2 (8.4 to 12.9) | 1.04 (0.78 to 1.39) | 0.97 (0.73 to 1.30) | ||
NOTE. Adjusted for age, sex, usual adult body mass index, stage of disease, and year of diagnosis (≤ 2004, 2005-2008, ≥ 2009).
Abbreviations: HR, hazard ratio; Ref, reference.
*
Kaplan-Meier method.
†
Cox proportional hazards regression model.
‡
Log-rank test.