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Table 3 Univariate and multivariate analysis (Cox regression models) assessing the relationship between baseline characteristics and time to treatment failure with AAP

From: Abiraterone acetate plus prednisone for the Management of Metastatic Castration-Resistant Prostate Cancer (mCRPC) without prior use of chemotherapy: report from a large, international, real-world retrospective cohort study

Covariate Frequency Univariate HR (95% CI) p-value1 Multivariate: no selection HR (95% CI) p-value2 Multivariate: backward selection HR (95% CI) p-value3
Age
 Unknown 0 N/A N/A  
 <  65 53 Reference Reference  
 65–75 188 1.011 (0.721–1.416) p-value = 0.9516 1.008 (0.711–1.429) p-value = 0.9651  
 >  75 240 1.230 (0.886–1.708) p-value = 0.2154 1.148 (0.808–1.632) p-value = 0.4414  
Comorbidities
 Unknown 0 N/A N/A  
 0 152 Reference Reference  
 1 143 1.253 (0.980–1.603) p-value = 0.0719 1.288 (0.994–1.669) p-value = 0.0556  
 2 89 1.148 (0.865–1.525) p-value = 0.3392 1.140 (0.845–1.540) p-value = 0.3909  
 ≥ 3 97 1.070 (0.805–1.422) p-value = 0.6413 0.937 (0.685–1.281) p-value = 0.6844  
Alanine aminotransferase (ALT)
 Unknown 127 1.024 (0.803–1.304) p-value = 0.8498 0.969 (0.696–1.350) p-value = 0.8534  
 ≤ 18 184 Reference Reference  
 >  18 170 0.825 (0.658–1.035) p-value = 0.0960 0.840 (0.657–1.073) p-value = 0.1623  
Alkaline phosphatase (ALP)
 Unknown 124 1.111 (0.861–1.435) p-value = 0.4175 0.879 (0.624–1.239) p-value = 0.4627 0.964 (0.718–1.296) p-value = 0.8091
 ≤ 119 182 Reference Reference Reference
 >  119 175 1.816* (1.451–2.273) p-value = < 0.0001 1.491* (1.160 - 1.915) p-value = 0.0018 1.510* (1.189–1.919) p-value = 0.0007
Aspartate aminotransferase (AST)
 Unknown 248 1.294 (1.017–1.645) p-value = 0.0358 1.049 (0.758–1.452) p-value = 0.7709  
 ≤ 24 118 Reference Reference  
 >  24 115 1.267 (0.953–1.684) p-value = 0.1034 1.183 (0.861–1.625) p-value = 0.3005  
Hemoglobin
 Unknown 106 0.850 (0.661–1.095) p-value = 0.2085 1.039 (0.746–1.448) p-value = 0.8196 1.064 (0.785–1.443) p-value = 0.6890
 ≤ 12.5 192 Reference Reference Reference
 >  12.5 183 0.666* (0.534 - 0.831) p-value = 0.0003 0.783* (0.618–0.991) p-value = 0.0414 0.779* (0.621–0.977) p-value = 0.0309
LDH
 Unknown 297 1.294 (0.996–1.681) p-value = 0.0536 1.228 (0.867–1.740) p-value = 0.2467  
 ≤ 277 92 Reference Reference  
 >  277 92 1.546* (1.124–2.125) p-value = 0.0074 1.278 (0.904–1.806) p-value = 0.2467  
PSA
 Unknown 25 1.540 (0.997–2.379) p-value = 0.0518 1.674 (1.053–2.663) p-value = 0.0295 1.593 (1.012–2.506) p-value = 0.0442
 ≤ 56.2 228 Reference Reference Reference
 >  56.2 228 1.663* (1.359 - 2.034) p-value = <.0001 1.308* (1.046–1.634) p-value = 0.0183 1.412* (1.139–1.749) p-value = 0.0116
Gleason
 Unknown 46 1.275 (0.905–1.796) p-value = 0.1643 1.153 (0.798–1.667) p-value = 0.4483  
 ≤ 7 204 Reference Reference  
 ≥ 8 231 1.266* (1.031–1.554) p-value = 0.0242 1.235 (0.997–1.529) p-value = 0.0532  
ECOG
 Unknown 202 1.658 (1.277–2.153) p-value = 0.0001 1.479 (1.124–1.947) p-value = 0.0052 1.538 (1.182–2.002) p-value = 0.0014
 0 110 Reference Reference Reference
 1 134 1.641* (1.240 - 2.171) p.-value = 0.0005 1.378* (1.024–1.855) p-value = 0.0343 1.447* (1.086–1.927) p-value = 0.0116
 2/3/4 35 1.793* (1.179 - 2.727) p-value = 0.0063 1.558* (1.002–2.422) p-value = 0.0489 1.642* (1.074–2.510) p-value = 0.0219
Location of node metastases
 Unknown 315 0.913 (0.702–1.189) p-value =0.5002 0.880 (0.663–1.167) p-value = 0.3747  
 Pelvic lymph node 80 Reference Reference  
 Iliac regional nodes 51 0.748 (0.512–1.094) p-value = 0.1346 0.763 (0.513–1.136) p-value = 0.1829  
 Pelvic and iliac nodes 35 1.111 (0.734–1.681) p-value = 0.6187 1.110 (0.725–1.700) p-value = 0.6310  
Location of metastases
 Unknown 16 1.034 (0.525–2.034) p-values = 0.9232 1.085 (0.537–2.191) p-value = 0.8203  
 Bone and lymph node metastases 429 1.092 (0.744–1.604) p-values = 0.6523 0.884 (0.589–1.326) p-value = 0.5509  
 Visceral 36 Reference Reference  
  1. *Denotes statistically significance
  2. 1Univariate HR contains the results from fitting a univariate Cox model with each covariate of interest
  3. 2Multivariate (no selection HR) contains the results from fitting a multivariate model with all covariates of interest included, no selection procedure was applied
  4. 3Multivariate (backward selection HR) contains the results from fitting a multivariate model in which covariates with a p-value < 0.10 in the univariate approach are included. A backward selection procedure was applied. Only the results of the final model are displayed. The covariates considered include age, number of comorbidities, ALP, ECOG, Gleason, hemoglobin, PSA. Please note that although age was not significant at the 10% level, it was included as it is considered clinically important. Only ALP, hemoglobin, PSA and ECOG were retained in the final model. The other variables were removed as their p-values were > 0.10