Table 2.
Univariate and multivariate analyses of risk factors for overall survival using a proportional hazard model
| Univariate analysis | Multivariate analysis | ||||||
|---|---|---|---|---|---|---|---|
| Variablea | HR | 95% CI | P | HR | 95% CI | P | |
| Sex | Male | 3.383 | 1.648–6.945 | 0.001 | |||
| Female | 1 | ||||||
| Age | 1.050 | 1.013–1.088 | 0.007 | ||||
| BMI | 0.904 | 0.819–0.997 | 0.044 | ||||
| Smoking Index | 1.001 | 1.000–1.001 | < 0.001 | 1.000 | 1.000–1.001 | 0.013 | |
| VC (%) | 0.98 | 0.963–0.997 | 0.021 | ||||
| FEV1/FVC (%) | 0.957 | 0.932–0.982 | 0.001 | ||||
| COPD | No | 1 | |||||
| Yes | 2.332 | 1.348–4.034 | 0.002 | ||||
| Surgical procedure | Sublobar resection | 1 | |||||
| Lobectomy | 1.042 | 0.599–1.814 | 0.884 | ||||
| Tumor size | 1.251 | 0.981–1.596 | 0.071 | ||||
| Histology | Adenocarcinoma | 1 | |||||
| Squamous cell carcinoma | 2.529 | 1.347–4.746 | 0.004 | ||||
| Other | 3.159 | 1.228–8.125 | 0.017 | ||||
| Histologic grade | Well differentiated | 1 | 1 | ||||
| Moderately differentiated | 3.002 | 1.530–5.888 | 0.001 | 2.205 | 1.115–4.360 | 0.023 | |
| Poorly differentiated | 4.805 | 2.309–9.998 | < 0.001 | 2.990 | 1.388–6.442 | 0.005 | |
| Pleural invasion | Absent | 1 | |||||
| Present | 2.107 | 1.219–3.641 | 0.008 | ||||
| Emphysema | Absent | 1 | 1 | ||||
| Present | 3.263 | 1.865–5.709 | < 0.001 | 1.927 | 1.050–3.537 | 0.034 | |
HR hazard ratio, CI confidence interval, BMI body mass index, VC vital capacity, FEV1 forced expiratory volume in 1 s; FVC forced vital capacity
aCategorical data are expressed as numbers, and continuous data are expressed as means ± standard deviation