Table 4.

Logistic regression analysis of in‐hospital mortality by volume category, including hospital as random effect

	Adjusted odds ratio	P
Hospital volume quintile
Very low	1·00 (reference)
Low	0·80 (0·68, 0·95)	0·010
Medium	0·78 (0·65, 0·93)	0·005
High	0·78 (0·65, 0·94)	0·010
Very high	0·58 (0·47, 0·73)	< 0·001
Sex
F	1·00 (reference)
M	0·95 (0·86, 1·05)	0·330
Age (years)
≤ 59	1·00 (reference)
60–74	2·45 (1·99, 3·01)	< 0·001
≥ 75	4·80 (3·94, 5·86)	< 0·001
Co‐morbidity score	1·27 (1·26, 1·28)	< 0·001
Emergency procedure
No	1·00 (reference)
Yes	1·53 (1·38, 1·70)	< 0·001

Values in parentheses are 95 per cent confidence intervals.