Table 1.
Baseline Clinical and Laboratory Parameters Considered for Inclusion in the Model (Univariate Analysis)
| Baseline Risk Factors | P Value | HR (95% CI) |
|---|---|---|
| LDH (> ULN [234 IU/L] vs. ≤ ULN) | <.0001 | 2.03 (1.50–2.75) |
| Bone metastases (≥10 vs. < 10)a | <.0001 | 1.95 (1.53–2.48) |
| ALP (> ULN [131 IU/L] vs. ≤ ULN) | <.0001 | 1.76 (1.37–2.26) |
| PSA (> 39.5 vs. ≤ 39.5 ng/mL) | <.0001 | 1.76 (1.39–2.23) |
| Lymph node metastases (present vs. absent) | <.0001 | 1.72 (1.36–2.17) |
| Hemoglobin (≤ LLN [12.7 g/dL] vs. > LLN) | <.0001 | 1.63 (1.28–2.03) |
| BPI (2–3 vs. 0–1) | .0015 | 1.56 (1.18–2.04) |
| Albumin (≤ 4 vs. > 4 g/dL) | .0074 | 1.38 (1.09–1.74) |
| Gleason score (≥ 8 vs. < 8) | .22 | 1.17 (0.91–1.49) |
| Time from start of androgen deprivation therapy to initiation of abiraterone acetate (≤ 36 vs. > 36 months) | .22 | 1.16 (0.92–1.46) |
| Prior prostatectomy (yes vs. no) | .52 | 1.08 (0.86–1.36) |
| Age (≥ 70 vs. < 70 years) | .57 | 1.07 (0.85–1.35) |
| M1 disease at diagnosis (yes vs. no) | .57 | 0.93 (0.70–1.22) |
| Prior radiation therapy (yes vs. no) | .47 | 0.92 (0.73–1.16) |
| ECOG PS (1 vs. 0) | .34 | 0.87 (0.65–1.16) |
| Testosterone (> 0.4 vs. ≤0.4 ng/mL)b | .04 | 1.67 (1.03–2.70) |
Note: Shaded factors were excluded from modeling.
Abbreviations: ALP = alkaline phosphatase; BPI = Brief Pain Inventory; CI = confidence interval; ECOG PS = Eastern Cooperative Oncology Group performance status; HR = hazard ratio; IU = international units; LDH = lactate dehydrogenase; LLN = lower limit of normal; PSA = prostate-specific antigen; rPFS = radiographic progression-free survival; ULN = upper limit of normal.
a
Individual bone lesions were counted up to 10, and then grouped as > 10 to 20 and > 20.
b
Measured by radioimmunoassay.