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Background: Colorectal surgery has evolved over the past decade as the laparoscopic era has dawned. The premise of laparoscopic surgery has been that a less invasive surgical modality might lead to decreased morbidity and health care utilization.
Aims: To determine the change in rate of bleeding, rate of reoperation, mortality, and health care utilization over the past decade in patients with postoperative bleeding after colon and rectal surgery.
Methods: This is a retrospective cohort study using the 2000 and the 2010 Nationwide Inpatient Sample (NIS), a nationally representative database of inpatient admissions. Inclusion was limited to patients with postoperative bleeding was defined as ICD-9 CM code for intraoperative bleeding, intraoperative hematoma, or lower gastrointestinal bleeding during the postoperative period and postoperative packed red blood cell transfusion. Adult patients were included if they had ICD-9 CM procedure code for laparoscopic colectomy, open colectomy, colostomy-related surgery, or proctectomy. A Charlson Comorbidity Index score was calculated for each patient. Outcomes included rate of bleeding, rate of reoperation, mortality, and inpatient charge in 2010 US dollars. Statistical significance was established if p<0.05.
Results: 360,091 patients had surgeries meeting inclusion criteria in 2000 and 381,741 patients had surgeries meeting inclusion criteria in 2010. Rate of postoperative bleeding over time is shown in Table 1. Bleeding decreased significantly among all surgery types between 2000 and 2010. Reoperation rate and mortality in patients with postoperative bleeding in shown in Table 2. Even as bleeding rate declined, reoperation rate and mortality rate among patients with postoperative bleeding increased, especially in open colectomy. However, overall mortality rate for patients undergoing colorectal surgery remained stable at 0.165% in 2000 versus 0.175% in 2010 (p=0.29).
Conclusion: Incidence of postoperative bleeding after colorectal surgery has decreased over the past decade. Laparoscopic colorectal surgery, which has a low postoperative bleeding rate, has accounted for much of the decrease; however, a significant decrease in bleeding rates was seen after open colectomy, proctectomy, and colostomy. Although mortality rates have increased in patients with postoperative bleeding, overall mortality after colorectal surgery has been stable. Further development of minimally invasive surgical techniques holds promise for further improvements in postoperative complication rates.
Table 1: Rate of postoperative bleeding by surgery type

	2000		2010		p value, bleeding rate
	n	Postoperative bleeding (%)	n	Postoperative bleeding (%)
Laparoscopic colectomy	-	-	79,021	0.20	-
Open colectomy	252,225	1.27	191,379	1.16 *	<0.01
Proctectomy	47,438	0.57	49,524	0.44 *	<0.01
Colostomy	60,428	3.19	61,817	2.13 *	<0.01
Overall	360,091	1.50	381,741	1.03 *	<0.01

* denotes statistically significant change
Table 2: Reoperation and mortality in patients with postoperative bleeding

	Reoperation (%)			Mortality (%)
	2000	2010	P value	2000	2010	P value
Laparoscopic colectomy	-	43.8	-	-	20.0	-
Open colectomy	6.8	19.5 *	<0.01	10.7	19.9 *	<0.01
Proctectomy	4.5	22.5 *	<0.01	7.4	8.7	0.60
Colostomy	4.4	15.2 *	<0.01	11.9	13.2	0.27
Overall	5.8	27.3 *	<0.01	11.0	17.0 *	<0.01

* denotes statistically significant change