Table 3.
Significant Predictors of VCF on Univariate and Multivariate Analysis
| Factor | Univariate P | Multivariable Fine and Grey Model |
||
|---|---|---|---|---|
| P | HR | 95% CI | ||
| Vertebral body collapse | < .001 | Global, < .001 | ||
| ≥ 50% VCF | .0189 | 6.92 | 1.38 to 34.77 | |
| < 50% VCF | < .001 | 8.98 | 4.48 to 18.00 | |
| No VCF but > 50% of vertebral body involved | < .001 | 4.46 | 2.08 to 9.57 | |
| Dose/fraction, Gy | < .001 | Global, < .001 | ||
| ≥ 24 | < .001 | 5.25 | 2.29 to 12.01 | |
| 20-23 | < .001 | 4.91 | 1.96 to 12.28 | |
| Alignment | .0027 | < .001 | 2.99 | 1.57 to 5.70 |
| Bone lesion type | < .001 | .0022 | 3.53 | 1.58 to 7.93 |
| Paraspinal/epidural extension | .0036 | NS | ||
NOTE. For vertebral body collapse, the reference is no VCF and less than 50% vertebral body involvement; for dose/fraction, the reference is ≤ 19 Gy/fraction; the reference for alignment was normal, and yphosis/scoliosis and subluxation/translation were grouped as only one patient had subluxation; and the reference for bone lesion was grouped according to mixed and osteoblastic tumor versus osteolytic, given that the majority of VCFs occurred in lytic tumors.
Abbreviations: HR, hazard ratio; NS, not significant; VCF, vertebral compression fracture.