Table 2.

Univariate Cox analyses predicting PFS and OS of corticosteroid switch

	N	PFS, months			OS, months
		Median (95%CI)	HR (95%CI)	p value	Median (95%CI)	HR (95%CI)	p value
Age at corticosteroid switch, years						1.17 (0.70–1.98)	0.563
≥ 70	81	5.5 (4.4–6.6)	0.75 (0.51–1.10)	0.139	18.1 (16.7–19.5)
< 70	49	3.2 (0.7–5.7)			23.5 (13.5–33.5)
ISUP grading at diagnosis						0.89 (0.51–1.55)	0.670
> 4	75	4.8 (3.5–6.1)	1.01 (0.67–1.53)	0.946	20.1 (14.3–25.9)
≤ 4	43	5.5 (2.9–8.1)			17.3 (13.4–21.2)
ECOG at corticosteroid switch						0.58 (0.34–0.97)	0.037
0	76	5.6 (4.2–7.0)	0.75 (0.51–1.10)	0.140	23.5 (17.3–29.7)
≥ 1	54	3.7 (2.2–5.2)			17.4 (13.8–21.0)
PSA at diagnosis, ng/mL						1.01 (0.58–176)	0.978
≥ 100	76	4.8 (3.7–5.9)	1.09 (0.71–1.65)	0.703	19.0 (14.2–23.8)
< 100	41	5.9 (5.0–6.8)			18.1 (14.2–22.0)
PSA at corticosteroid switch, ng/mL						0.37 (0.21–0.54)	< 0.001
≤ 20	64	6.9 (5.8–8.0)	0.60 (0.41–0.87)	0.007	25.9 (21.7–30.1)
>  20	66	3.7 (2.8–4.6)			15.6 (13.3–17.9)
mCRPC-free survival, months						0.51 (0.30–0.87)	0.014
≥ 18	53	6.9 (5.2–8.6)	0.58 (0.40–0.85)	0.005	23.6 (17.7–29.5)
<  18	77	3.2 (2.0–4.4)			17.1 (15.1–19.1)
Time to progression on A + P, months						0.98 (0.58–1.65)	0.930
≥ 8	50	6.2 (4.5–7.9)	0.75 (0.51–1.10)	0.144	17.5 (15.3–19.7)
< 8	80	4.2 (2.6–5.8)			19.0 (14.9–23.1)
PSA response on A + P						1.46 (0.86–2.46)	0.161
Decline ≥50%	72	4.9 (3.8–6.0)	1.11 (0.75–1.62)	0.608	17.4 (16.2–18.7)
Decline < 50%	58	5.4 (3.6–7.2)			28.3 (14.9–41.7)

A: abiraterone acetate; CI: confidence interval; ECOG: Eastern Cooperative Oncology Group; HR: hazard ratio; ISUP: The International Society of Urological Pathology; mCRPC: metastatic castration-resistant prostate cancer; OS: overall survival; P: prednisone; PFS: progression-free survival; PSA: prostate-specific antigen