Table 4.

 Odds ratio (95% confidence intervals) adjusted for clustering (133 036 patients in 219 providers) for breast conserving surgery and social factors, admission type, and admission period for women admitted with breast cancer (1 April 1999 to 31 March 2006)

Variable	Total*	No (%) with breast conserving surgery†	Univariable model			Multivariable model‡
			Odds ratio (95% CI)	P value§		Odds ratio (95% CI)	P value§
Fifth of index of multiple deprivation:
1 (most deprived)	20 849	11 256 (54.0)	1	<0.001		1	<0.001
2	24 608	14 383 (58.4)	1.10 (1.05 to 1.14)			1.09 (1.05 to 1.13)
3	28 582	17 099 (59.8)	1.12 (1.08 to 1.17)			1.10 (1.06 to 1.15)
4	30 037	18 557 (61.8)	1.22 (1.18 to 1.27)			1.19 (1.14 to 1.24)
5 (least deprived)	28 960	18 445 (63.7)	1.25 (1.20 to 1.30)			1.21 (1.16 to 1.26)
Age group (years):
50-59	47 011	32 113 (68.3)	1	<0.001		1	<0.001
60-69	42 026	27 076 (64.4)	0.83 (0.81 to 0.86)			0.76 (0.72 to 0.80)
70-79	30 577	14 719 (48.1)	0.42 (0.41 to 0.43)			0.43 (0.41 to 0.45)
80-89	12 220	5262 (43.1)	0.33 (0.32 to 0.35)			0.42 (0.39 to 0.45)
≥90	1202	570 (47.4)	0.39 (0.34 to 0.43)			0.44 (0.34 to 0.52)
Admission type:
Elective	132 172	79 306 (60.0)	1	<0.001		1	0.004
Emergency	864	434 (50.2)	0.68 (0.60 to 0.78)			0.81 (0.70 to 0.93)
Admission period (reporting period 1 April to 31 March):
Per year	—	—	1.028 (1.021 to 1.034)	<0.001		1.027 (1.017 to 1.038)	<0.001
Interaction between age group and admission period:
50-59×period	—	—	—	—		1	<0.001
60-69×period	—	—	—	—		1.027 (1.012 to 1.042)
70-79×period	—	—	—	—		0.992 (0.977 to 1.007)
80-89×period	—	—	—	—		0.930 (0.911 to 0.950)
≥90×period	—	—	—	—		0.973 (0.917 to 1.031)

*Figures based on first admission for breast cancer patients.

†As percentage of total breast cancer surgery.

‡Intraclass correlation coefficient 0.065 (0.054 to 0.080).

§Wald tests of significance.