Table 2.
Threshold effect analysis of age on OS, BCSS, and DFS among 1054 breast patients.
| Variable | Model 1 | P-value | Model 2 | P-value | Model 3 | P-value |
|---|---|---|---|---|---|---|
| HR (95% CI) * | HR (95% CI) * | HR (95% CI) * | ||||
| OS | ||||||
| Age, years☆ | 1.02(1.00-1.04) | 0.055 | 1.02(1.00-1.04) | 0.031 | 1.03(1.01-1.05) | 0.021 |
| Inflection point★ | ||||||
| Age<44 years | 0.93 (0.87, 1.00) | 0.039 | 0.94 (0.88, 1.01) | 0.073 | 0.94 (0.88, 1.01) | 0.074 |
| Age>44 years | 1.04 (1.01, 1.06) | 0.002 | 1.04 (1.01, 1.06) | 0.002 | 1.05 (1.02, 1.08) | 0.001 |
| P for log likelihood ratio test | 0.015 | 0.025 | 0.017 | |||
| BCSS | ||||||
| Age, years☆ | 1.02(1.00-1.05) | 0.103 | 1.02(1.00-1.05) | 0.057 | 1.02(1.00-1.05) | 0.063 |
| Inflection point★ | ||||||
| Age<44 years | 0.90 (0.84, 0.97) | 0.007 | 0.93 (0.85, 1.01) | 0.100 | 0.93 (0.85, 1.02) | 0.119 |
| Age>44 years | 1.05 (1.02, 1.08) | 0.001 | 1.05 (1.02, 1.08) | 0.002 | 1.05 (1.02, 1.09) | 0.002 |
| P for log likelihood ratio test | 0.004 | 0.037 | 0.038 | |||
| DFS | ||||||
| Age, years☆ | 1.01(0.99-1.02) | 0.275 | 1.01(0.99-1.02) | 0.180 | 1.01(0.99-1.03) | 0.171 |
| Inflection point★ | ||||||
| Age<41 years | 0.92 (0.86, 0.97) | 0.004 | 0.92 (0.87, 0.98) | 0.008 | 0.92 (0.86, 0.98) | 0.006 |
| Age>41 years | 1.02 (1.01, 1.04) | 0.010 | 1.02 (1.00, 1.04) | 0.013 | 1.02 (1.01, 1.04) | 0.007 |
| P for log likelihood ratio test | 0.004 | 0.007 | 0.004 | |||
Model 1: unadjusted. Model 2: adjusted for tumor size, molecular subtype. Model 3: adjusted for tumor size, molecular subtype, lymph nodes in the axilla status, operation type, adjuvant therapy, hormonal therapy. *Cox proportional hazards models were used to estimate HRs and 95% CIs. ☆Fitting model by standard Cox proportional hazards model. ★Fitting model by two-piecewise Cox proportional hazards model.
The bold values denote statistical significance at P<0.05 level.