Table 1. Multivariate Analysis for Overall Survival in the Immunotherapy Pooled Cohort (Bootstrap Internal Validation).
| Variable | HR (95% CI) | P Value | Internal Validation BCA HR (95% CI) |
|---|---|---|---|
| Age, y | |||
| <70 | 1 [Reference] | .10 | |
| ≥70 | 1.35 (0.94-1.93) | 0.93-1.96 | |
| Smoking history | |||
| Nonsmoker | 1 [Reference] | .89 | |
| Smoker | 0.96 (0.58-1.60) | 0.60-1.66 | |
| Histologic subtype | |||
| Nonsquamous | 1 [Reference] | .10 | |
| Squamous | 1.30 (0.95-1.79) | 0.94-1.87 | |
| No. of metastatic sites | |||
| <2 | 1 [Reference] | .004 | |
| ≥2 | 1.56 (1.15-2.12) | 1.11-2.22 | |
| Lines of immunotherapy | |||
| <2 | 1 [Reference] | .56 | |
| ≥2 | 0.91 (0.67-1.24) | 0.65-1.25 | |
| Performance status before immunotherapy | |||
| 0 or 1 | 1 [Reference] | <.001 | |
| ≥2 | 2.08 (1.38-3.13) | 1.27-3.70 | |
| Lactate dehydrogenase (ULN) | |||
| Low or normal | 1 [Reference] | .04 | |
| High | 1.36 (1.02-1.83) | 0.98-1.92 | |
| Derived neutrophil/lymphocyte ratio | |||
| ≤3 | 1 [Reference] | <.001 | |
| >3 | 1.70 (1.27-2.28) | 1.29-2.41 | |
| Albumin level, g/dL | |||
| ≥3.5 | 1 [Reference] | .001 | |
| <3.5 | 1.69 (1.23-2.34) | 1.17-2.48 |
Abbreviations: BCA, bias-corrected and accelerated bootstrap interval; ULN, upper limit of normal.
SI conversion factors: To convert lactate dehydrogenase to microkatals per liter, multiply by 0.0167.