Table 3 Multivariate regression analysis for disease specific survival (DSS) in patients taking metformin at time of diagnosis
Covariate | Category | Comparator | P-value | Hazard Ratio | 95% CI |
|---|---|---|---|---|---|
Age | |||||
70–74 | 65–69 | 0.8138 | 0.958 | 0.673–1.364 | |
75–79 | 0.0035 | 1.636 | 1.175–2.277 | ||
80–84 | 0.0067 | 1.726 | 1.163–2.561 | ||
85–90 | 0.0450 | 1.793 | 1.013–3.175 | ||
= > 90 | 0.0275 | 2.832 | 1.122–7.148 | ||
Gender | |||||
Male | Female | 0.1428 | 1.283 | 0.919–1.791 | |
Treatment type | |||||
CRT+/−surgery | RT +/− surgery | 0.2510 | 1.218 | 0.870–1.704 | |
Surgery+/−RT/CRT | 0.1351 | 1.247 | 0.933–1.667 | ||
Elixhauser Comorbidity Index Score | |||||
1 | 0 | 0.8172 | 1.040 | 0.743–1.457 | |
2 | 0.3511 | 1.218 | 0.805–1.842 | ||
3+ | 0.0078 | 1.582 | 1.128–2.218 | ||
Primary site | |||||
Hypopharynx | Glottic larynx | <.0001 | 4.488 | 3.269–6.162 | |
Nasopharynx | < 0.001 | 2.957 | 1.757–4.977 | ||
Supraglottic larynx | <.0001 | 2.993 | 2.189–4.093 | ||
Metformin use | |||||
Control (no metformin exposure) | Case (metformin use at time of diagnosis) | 0.9980 | 1.000 | 0.695–1.440 | |