Table 2.
Unadjusted 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 | .2819 | .0763 | ||||
| Never | 564/614 | 8.9 (8.0 to 9.6) | Ref | Ref | ||
| Ever | 311/366 | 9.9 (8.2 to 10.7) | 0.93 (0.81 to 1.07) | 0.88 (0.77 to 1.01) | ||
| Resectable | .2249 | .0908 | ||||
| Never | 153/187 | 19.4 (16.7 to 23.5) | Ref | Ref | ||
| Ever | 70/97 | 22.8 (18.6 to 30.9) | 0.84 (0.63 to 1.12) | 0.78 (0.59 to 1.04) | ||
| Locally advanced | .0093 | .0058 | ||||
| Never | 211/222 | 8.1 (6.9 to 9.5) | Ref | Ref | ||
| Ever | 111/132 | 10.2 (8.9 to 12.9) | 0.74 (0.58 to 0.93) | 0.72 (0.58 to 0.91) | ||
| Metastatic | .4370 | .7096 | ||||
| Never | 199/204 | 5.3 (4.6 to 6.1) | Ref | Ref | ||
| Ever | 130/137 | 4.9 (3.8 to 5.9) | 1.09 (0.88 to 1.36) | 1.04 (0.84 to 1.30) | ||
| Metformin naïve | .8889 | .5374 | ||||
| Never | 564/614 | 8.9 (8.0 to 9.6) | Ref | Ref | ||
| Ever | 72/85 | 10.2 (8.4 to 12.9) | 1.02 (0.80 to 1.30) | 0.93 (0.72 to 1.18) | ||
Abbreviations: HR, hazard ratio; Ref, reference.
*
Kaplan-Meier method.
†
Cox proportional hazards regression model.
‡
Log-rank test.