Table 2 Multivariate regression analysis for overall survival (OS) in patients taking metformin at the time of diagnosis
Covariate | Category | Comparator | P-value | Hazard Ratio | 95% CI |
|---|---|---|---|---|---|
Age | |||||
70–74 | 65–69 | 0.2574 | 1.152 | 0.902–1.471 | |
75–79 | <.0001 | 1.879 | 1.485–2.379 | ||
80–84 | <.0001 | 2.309 | 1.776–3.001 | ||
85–90 | < 0.001 | 2.257 | 1.545–3.298 | ||
= > 90 | <.0001 | 4.457 | 2.614–7.599 | ||
Gender | |||||
Male | Female | 0.2969 | 1.124 | 0.903–1.399 | |
Treatment type | |||||
CRT+/−surgery | RT +/− surgery | 0.6839 | 1.053 | 0.821–1.350 | |
Surgery+/−RT/CRT | 0.7389 | 1.034 | 0.851–1.256 | ||
Elixhauser Comorbidity Index Score | |||||
1 | 0 | 0.1105 | 1.194 | 0.960–1.484 | |
2 | 0.0618 | 1.298 | 0.987–1.708 | ||
3+ | <.0001 | 1.902 | 1.524–2.375 | ||
Primary site | |||||
Hypopharynx | Glottic larynx | <.0001 | 2.933 | 2.336–3.683 | |
Nasopharynx | 0.0101 | 1.679 | 1.131–2.492 | ||
Supraglottic larynx | <.0001 | 2.296 | 1.867–2.825 | ||
Metformin use | |||||
Control (no metformin exposure) | Case (metformin use at time of diagnosis) | 0.4314 | 1.104 | 0.863–1.413 | |