Table 3.
Frailty Model Sensitivity Analyses
| Factor and Outlier Status | Hazard Ratio | 95% CI |
|---|---|---|
| Margin-negative patients | ||
| High outlier | 1.05 | 0.95 to 1.17 |
| Nonoutlier | 1.00 | |
| Low outlier | 0.71 | 0.58 to 0.86 |
| Low v high outlier (ref) | 0.67 | 0.54 to 0.83 |
| Neoadjuvant XRT* | ||
| High outlier | 1.23 | 0.94 to 1.61 |
| Nonoutlier | 1.00 | |
| Low outlier | 0.67 | 0.39 to 1.14 |
| Low v high outlier (ref) | 0.55 | 0.32 to 0.94 |
| ≥ 12 lymph nodes pathologically evaluated* | ||
| High outlier | 1.13 | 0.99 to 1.28 |
| Nonoutlier | 1.00 | |
| Low outlier | 0.73 | 0.58 to 0.91 |
| Low v high outlier (ref) | 0.64 | 0.50 to 0.83 |
| Excluding hospitals with no margin-positive patients* | ||
| High outlier | 1.12 | 1.02 to 1.23 |
| Nonoutlier | 1.00 | |
| Low outlier | 0.59 | 0.47 to 0.74 |
| Low v high outlier (ref) | 0.52 | 0.41 to 0.67 |
| Alternate RAMP stratification† | ||
| High outlier | 1.14 | 1.04 to 1.25 |
| At-risk high outlier | 1.02 | 0.93 to 1.12 |
| Nonoutlier | 1.00 | |
| Low nonoutlier | 0.78 | 0.65 to 0.94 |
| Low outlier | 0.68 | 0.57 to 0.82 |
Abbreviations: RAMP, risk-adjusted margin positivity rate; ref, reference; XRT, radiotherapy.
*
Models were restricted to patients who received neoadjuvant XRT, who had ≥ 12 lymph nodes evaluated pathologically, and who were treated at hospitals reporting no observed margin-positive patients.
†
Alternate stratification as follows: high outlier: observed-to-expected ratio (O/E) > 1 and P < .05; at-risk high outlier: O/E > 1 and P > .05 but < .1; low nonoutlier: O/E < 1 and P > .05 but < .1; and low outlier: O/E < 1 and P < .05.