Hospitalized ulcerative colitis patients have an elevated risk of thromboembolic events

Table 1 Characteristics of non-surgical and surgical groups

	Non-surgical discharges			Surgical discharges
	Ulcerative colitis	Diverticulitis	Acute respiratory failure	Ulcerative colitis	Diverticulitis	Colorectal cancer
N	7302	25 138	50 905	880	6860	20 336
Estimated population totals1	974 206	3 805 999	6 296 383	127 327	944 275	2 910 807
Age (mean)	49.8	67.7	62.3	47.6	62.2	69.6
Male (%)	46	35a	48	54	43	49
Length of stay (mean)	7.1d	6.6d	11.7d	16.9d	13.1d	13.9d
Atrial fibrillation (%)	2.9	4.5a	11.3c	2.3	3.2	5.1e
Obesity (%)	1.3	2.5a	2.2c	1.1	2.3	1.5
History of VTE (%)	0.13	0.01	0.11	0	0.06	0.18
Mortality (%)	1.6	1.6	23.6	2.5	4.0	3.7

VTE: Venous thromboembolism.

¹Calculated by applying probability weight to each observation.

^aP < 0.05, non-surgical discharges with ulcerative colitis vs non-surgical discharges with diverticulitis;

^cP < 0.05, non-surgical discharges with ulcerative colitis vs non-surgical discharges with respiratory failure;

^eP < 0.05, surgical discharges with ulcerative colitis vs surgical discharges with colorectal cancer.

Table 2 Estimated population percentages of non-surgical discharges which had thromboembolic events and comparison of event rates

Thromboembolic event	Ulcerative colitis vs diverticulitis		Ulcerative colitis vs respiratory failure
	Rate difference, % (95% CI)	P value	Rate difference, % (95% CI)	P value
Deep venous thrombosis	1.05 (1.69 to 0.41)	0.01	0.48 (-0.18 to 1.14)	0.2
Pulmonary embolism	0.31 (0.03 to 0.59)	0.03	-0.56 (-0.92 to -0.2)	0.002
Venous thrombo-embolism	1.26 (0.56 to 1.97)	0.004	0.04 (-0.72 to 0.8)	0.9
Stroke	0.03 (-0.28 to 0.34)	0.9	-1.11 (-1.52 to -0.7)	< 0.001
Arterial thrombo-embolism	0.01 (-0.21 to 0.24)	0.9	-0.33 (-0.59 to -0.08)	0.01

Table 3 Estimated population percentages of surgical discharges with thromboembolic events and comparison of event rates

Thromboembolic event	Ulcerative colitis vs diverticulitis		Ulcerative colitis vs respiratory failure
	Rate difference, % (95% CI)	P value	Rate difference, % (95% CI)	P value
Deep venous thrombosis	0.7 (-0.98 to 2.39)	0.4	0.42 (-1.25 to 2.1)	0.6
Pulmonary embolism	-0.36 (-0.95 to 0.23)	0.2	-0.42 (-0.92 to 0.09)	0.1
Venous thrombo-embolism	0.34 (-1.42 to 2.09)	0.7	0.01 (-1.61 to 1.72)	1.0
Stroke	-0.01 (-0.67 to 0.65)	1.0	-0.14 (-0.75 to 0.48)	0.7
Arterial thrombo-embolism	0.041	-2	0.061	-2

¹Confidence interval not available because there were no events after 1988;

²P value not calculable because there were no events in the ulcerative colitis group after 1988.