Table 3. Multivariate stratified Cox regression for 84 month survival.

Stratified interaction non-PH Cox regression Model (84 month follow-up)
	Private	Public	Married	Not Married
SES1	1	1	1	1
SES2	1.15	1.24***	1.34***	1.19*
SES3	0.94	1.07	1.12*	1.11
SES4	0.97	1.18***	1.23***	1.17**
SES5	1.09	1.25***	1.39***	1.22***
SES Unknown	0.81	1.21***	1.16*	1.16
Global Test	2.22 (P = 0.82)	3.26 (P = 0.66)	6.29 (P = 0.28)	6.72 (P = 0.24)
Wald Test *SES group	Chi2(5) =  6.73 (P = 0.24)	Chi2(5) = 24.17 (P = 0.00)	Chi2(5) = 38.83 (P = 0.00)	Chi2(5) = 8.36 (P = 0.13)
Number of Observations	2902	7408	6875	3435
	Gleason grade 5–7	Gleason grade >7	Stage II	Stage III
SES1	1	1	1	1
SES2	1.38***	1.25**	1.48***	1.64*
SES3	1.21**	1.05	1.28**	1.58*
SES4	1.19**	1.28***	1.27**	1.62**
SES5	1.58***	1.30***	1.50***	1.83***
SES Unknown	1.24*	1.15	1.24*	0.93
Global Test	4.29 (P = 0.49)	2.13 (P = 0.83)	4.56 (P = 0.47)	4.94 (P = 0.42)
Wald Test *SES group	Chi2(5) = 38.67 (P = 0.00)	Chi2(5) = 13.92 (P = 0.02)	Chi2(5) = 24.84 (P = 0.00)	Chi2(5) = 10.43 (P = 0.06)
Number of Observations	4753	2041	4119	748
	Leinster	Connacht	Munster	Ulster
SES1	1	1	1	1
SES2	1.35***	1.47**	1.06	0.80
SES3	1.15*	1.23	0.93	0.97
SES4	1.26***	1.35**	1.03	0.97
SES5	1.59***	1.31*	1.10	0.86
SES Unknown	1.28**	1.18	1.08	0.59
Global Test	0.78 (P = 0.97)	4.47 (P = 0.48)	2.45 (0.78)	5.59 (P = 0.35)
Wald Test *SES group	Chi2(5) = 61.31 P = 0.00)	Chi2(5) = 7.96 (P = 0.15)	Chi2(5) = 4.81 (P = 0.44)	Chi2(5) = 4.24 (P = 0.51)
Number of Observations	4901	1458	3118	833

Notes: 1.) Hazard Ratios for not surviving at 36 months reported with clustered standard errors.

2.) Significance: * (P<0.10), ** (P<0.05), *** (P<0.01).

3.) “SES”- Socio-economic status.