FEATURE
Oral Antibiotic Bowel Preparation Significantly Reduces Surgical Site Infection Rates and Readmission Rates in Elective Colorectal Surgery Melanie S. Morris, MD, Laura A. Graham, MPH, Daniel I. Chu, MD, Jamie A. Cannon, MD, and Mary T. Hawn, MD, MPH
Objective: To determine the relationship between oral antibiotic bowel preparation (OABP) and surgical site infection (SSI) rates in a national colectomy cohort. Background: OABP for elective colorectal surgery has fallen out of favor. Large cohort studies show that OABP is associated with a 50% reduction in SSI after colectomy. Methods: A retrospective analysis of the National Surgical Quality Improvement Program colectomy cohort from 2011 to 2012 was performed to examine the association between use of OABP and outcomes of SSI, length of stay (LOS), and readmission after elective colectomy. Univariate and multivariable analyses for SSI were performed. Results: The cohort included 8415 colorectal operations of which 5291 (62.9%) had a minimally invasive surgical (MIS) approach. Overall, 25.6% had no bowel preparation, 44.9% had mechanical bowel preparation (MBP) only, and 29.5% received OABP. The SSI rate was 11.1%, and it varied by preparation type: 14.9% no preparation, 12.0% MBP, and 6.5% OABP (P < 0.001). OABP group had significantly shorter hospital LOS: (median = 4, interquartile range: 3–6) versus other preparations (median LOS = 5) (P < 0.001). Readmission rates were lowest in OABP (8.1%) and highest in the no preparation group (11.8%). Multivariable logistic regressions found OABP associated with lower SSI [adjusted odds ratio (ORadj ) = 0.46, 95% confidence interval (CI): 0.36–0.59]. Stratified models found OABP protective for SSI for both open procedures (ORadj = 0.40, 95% CI: 0.30–0.53) and MIS procedures (ORadj = 0.48, 95% CI: 0.36–0.65). Conclusions: OABP is associated with reduced SSI rates, shorter LOS, and fewer readmissions. Adoption of OABP before elective colectomy would reduce SSI without effecting LOS. The practice of MBP alone should be abandoned. Keywords: colorectal surgery, length of stay, mechanical bowel preparation, oral antibiotic bowel preparation, readmission, surgical site infection (Ann Surg 2015;261:1034–1040)
M
echanical bowel preparation (MBP) with the use of oral antibiotics is effective in reducing surgical site infection (SSI) after elective colorectal surgery.1–4 More recent trials and a Cochrane meta-analysis show that omitting bowel preparation before colorectal surgery was not associated with increased complications.5,6 However, these studies compared MBP alone without oral antibiotics to no preparation. Recently, several large retrospective studies have demonstrated that oral antibiotic bowel preparation (OABP), but not MBP, is From the Department of Surgery at the University of Alabama, Birmingham, AL. Disclosure: The authors have no conflicts of interest to disclose, and they received no funding for this study. Reprints: Melanie S. Morris, MD, Department of Surgery, Section of Gastrointestinal Surgery, 428 Kracke Bldg, 1720 2nd Ave S, Birmingham, AL 35294. E-mail: [email protected]. C 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright ISSN: 0003-4932/15/26106-1034 DOI: 10.1097/SLA.0000000000001125
1034 | www.annalsofsurgery.com
associated with reduced SSI rates after elective colorectal surgery.7–9 A main limitation of these studies was that the majority of procedures were performed with an open approach. These conflicting findings on OABP, MBP, and no preparation; the emphasis on omitting preparation in enhanced recovery protocols (ERPs); and patient preference and intolerance to preparations have likely led to decreased usage of bowel preparation in recent years. The field of colorectal surgery has experienced revolutionary change in approach to surgery since the Clinical Outcomes of Surgical Therapy trial championed the safety and efficacy of a minimally invasive approach to colon cancer in 2004.10 Furthermore, the increased emphasis on reducing the length of stay (LOS) has led to the adoption of ERP. ERPs were developed to improve efficiency and reduce complications after colorectal surgery. ERPs minimize surgical stress and organ dysfunction during the perioperative period by using multimodal strategies such as nonopioid analgesia, minimizing intravenous fluids, early postoperative feeding, early ambulation, and omitting bowel preparations.11 ERPs in colorectal surgery have demonstrably reduced LOS from 8 to 12 days with traditional recovery pathways to 2 to 3 days.12 Traditional criteria for discharge include return of bowel function, which occurs more quickly if MBP is avoided. However, there are limited data on whether ERPs reduce postoperative complications. Although use of OABP has been associated with lower SSI and readmission rates in cohorts comprised primarily of open approaches in colorectal surgery, it is not clear whether OABP will have similar effects in patients undergoing minimally invasive surgical (MIS) colorectal surgery. With increased adoption of ERP and bundled care practices aimed primarily at reducing LOS, we sought to understand the contribution of OABP to the recovery of patients after both minimally invasive and open colorectal surgery. We therefore used the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) procedure targeted colectomy cohort to determine whether OABP was associated with reduced postoperative SSI rates, LOS and readmission rates after elective colorectal surgery.
METHODS The study population consisted of all colectomy cases collected by the American College of Surgeons’ NSQIP in 2011 and 2012 for the Colectomy Targeted Participant Use Data File. Cases were collected across 121 NSQIP sites by trained surgical clinical reviewers.13 Patients were excluded from analysis if they were missing information on the type of preoperative preparation that was administered or if their surgery was identified as non-elective or emergent by NSQIP. A small number of cases were coded as clean cases and these were re-classified as clean contaminated as it is impossible for a colectomy to be a clean case. The primary outcomes measured were: (1) postoperative surgical site infection (SSI), (2) in-hospital LOS, and (3) all-cause readmission within 30 days after colectomy. A composite postoperative SSI was defined as the occurrence of a superficial, deep incisional, Annals of Surgery r Volume 261, Number 6, June 2015
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Annals of Surgery r Volume 261, Number 6, June 2015
Oral Antibiotic Bowel Preparation
TABLE 1. Study Population Demographics and Comorbidities
None, N (%)
Mechanical Only, N (%)
OABP ± Mechanical, N (%)
8415 4288 (51.0) 4127 (49.0)
2150 (25.6) 1119 (52.1) 1031 (48.0)
3779 (44.9) 1939 (51.3) 1840 (48.7)
2486 (29.5) 1230 (49.5) 1256 (50.5)
6893 (81.9) 617 (7.3) 316 (3.8) 62 (52–72)
1658 (77.1) 174 (8.1) 66 (3.1) 62 (52–73)
3059 (81.0) 301 (8.0) 164 (4.3) 62 (52–72)
2176 (87.5) 142 (5.7) 86 (3.5) 61 (52–71)
7224 (85.9) 835 (9.9) 356 (4.2)
1861 (86.6) 182 (8.5) 107 (5.0)
3226 (85.4) 402 (10.6) 151 (4.0)
2137 (86.0) 251 (10.1) 98 (3.9)
6963 (82.8) 1452 (17.3)
1775 (82.6) 375 (17.4)
3141 (83.1) 638 (16.9)
2047 (82.3) 439 (17.7)
8255 (98.1) 127 (1.5) 14 (0.2)
2095 (97.4) 48 (2.2) 04 (0.2)
3708 (98.1) 54 (1.4) 08 (0.2)
2452 (98.6) 25 (1.0) 02 (0.1)
8040 (95.5) 375 (4.5)
2057 (95.7) 93 (4.3)
3603 (95.3) 176 (4.7)
2380 (95.7) 106 (4.3)
0.72
8373 (99.5) 42 (0.5)
2139 (99.5) 11 (0.5)
3760 (99.5) 19 (0.5)
2474 (99.5) 12 (0.5)
0.99
7838 (93.1) 553 (6.6) 24 (0.3)
1974 (91.8) 168 (7.8) 08 (0.4)
3517 (93.1) 251 (6.6) 11 (0.3)
2347 (94.4) 134 (5.4) 05 (0.2)
4436 (52.7) 3979 (47.3)
1161 (54.0) 989 (46.0)
1910 (50.5) 1869 (49.5)
1365 (54.9) 1121 (45.1)
0.001
8381 (99.6) 34 (0.4)
2138 (99.4) 12 (0.6)
3762 (99.6) 17 (0.5)
2481 (99.8) 05 (0.2)
0.13
7982 (94.9) 433 (5.2)
1989 (92.5) 161 (7.5)
3606 (95.4) 173 (4.6)
2387 (96.0) 99 (4.0)
Oral Antibiotic Bowel Preparation Significantly Reduces Surgical Site Infection Rates and Readmission Rates in Elective Colorectal Surgery Melanie S. Morris, MD, Laura A. Graham, MPH, Daniel I. Chu, MD, Jamie A. Cannon, MD, and Mary T. Hawn, MD, MPH
Objective: To determine the relationship between oral antibiotic bowel preparation (OABP) and surgical site infection (SSI) rates in a national colectomy cohort. Background: OABP for elective colorectal surgery has fallen out of favor. Large cohort studies show that OABP is associated with a 50% reduction in SSI after colectomy. Methods: A retrospective analysis of the National Surgical Quality Improvement Program colectomy cohort from 2011 to 2012 was performed to examine the association between use of OABP and outcomes of SSI, length of stay (LOS), and readmission after elective colectomy. Univariate and multivariable analyses for SSI were performed. Results: The cohort included 8415 colorectal operations of which 5291 (62.9%) had a minimally invasive surgical (MIS) approach. Overall, 25.6% had no bowel preparation, 44.9% had mechanical bowel preparation (MBP) only, and 29.5% received OABP. The SSI rate was 11.1%, and it varied by preparation type: 14.9% no preparation, 12.0% MBP, and 6.5% OABP (P < 0.001). OABP group had significantly shorter hospital LOS: (median = 4, interquartile range: 3–6) versus other preparations (median LOS = 5) (P < 0.001). Readmission rates were lowest in OABP (8.1%) and highest in the no preparation group (11.8%). Multivariable logistic regressions found OABP associated with lower SSI [adjusted odds ratio (ORadj ) = 0.46, 95% confidence interval (CI): 0.36–0.59]. Stratified models found OABP protective for SSI for both open procedures (ORadj = 0.40, 95% CI: 0.30–0.53) and MIS procedures (ORadj = 0.48, 95% CI: 0.36–0.65). Conclusions: OABP is associated with reduced SSI rates, shorter LOS, and fewer readmissions. Adoption of OABP before elective colectomy would reduce SSI without effecting LOS. The practice of MBP alone should be abandoned. Keywords: colorectal surgery, length of stay, mechanical bowel preparation, oral antibiotic bowel preparation, readmission, surgical site infection (Ann Surg 2015;261:1034–1040)
M
echanical bowel preparation (MBP) with the use of oral antibiotics is effective in reducing surgical site infection (SSI) after elective colorectal surgery.1–4 More recent trials and a Cochrane meta-analysis show that omitting bowel preparation before colorectal surgery was not associated with increased complications.5,6 However, these studies compared MBP alone without oral antibiotics to no preparation. Recently, several large retrospective studies have demonstrated that oral antibiotic bowel preparation (OABP), but not MBP, is From the Department of Surgery at the University of Alabama, Birmingham, AL. Disclosure: The authors have no conflicts of interest to disclose, and they received no funding for this study. Reprints: Melanie S. Morris, MD, Department of Surgery, Section of Gastrointestinal Surgery, 428 Kracke Bldg, 1720 2nd Ave S, Birmingham, AL 35294. E-mail: [email protected]. C 2015 Wolters Kluwer Health, Inc. All rights reserved. Copyright ISSN: 0003-4932/15/26106-1034 DOI: 10.1097/SLA.0000000000001125
1034 | www.annalsofsurgery.com
associated with reduced SSI rates after elective colorectal surgery.7–9 A main limitation of these studies was that the majority of procedures were performed with an open approach. These conflicting findings on OABP, MBP, and no preparation; the emphasis on omitting preparation in enhanced recovery protocols (ERPs); and patient preference and intolerance to preparations have likely led to decreased usage of bowel preparation in recent years. The field of colorectal surgery has experienced revolutionary change in approach to surgery since the Clinical Outcomes of Surgical Therapy trial championed the safety and efficacy of a minimally invasive approach to colon cancer in 2004.10 Furthermore, the increased emphasis on reducing the length of stay (LOS) has led to the adoption of ERP. ERPs were developed to improve efficiency and reduce complications after colorectal surgery. ERPs minimize surgical stress and organ dysfunction during the perioperative period by using multimodal strategies such as nonopioid analgesia, minimizing intravenous fluids, early postoperative feeding, early ambulation, and omitting bowel preparations.11 ERPs in colorectal surgery have demonstrably reduced LOS from 8 to 12 days with traditional recovery pathways to 2 to 3 days.12 Traditional criteria for discharge include return of bowel function, which occurs more quickly if MBP is avoided. However, there are limited data on whether ERPs reduce postoperative complications. Although use of OABP has been associated with lower SSI and readmission rates in cohorts comprised primarily of open approaches in colorectal surgery, it is not clear whether OABP will have similar effects in patients undergoing minimally invasive surgical (MIS) colorectal surgery. With increased adoption of ERP and bundled care practices aimed primarily at reducing LOS, we sought to understand the contribution of OABP to the recovery of patients after both minimally invasive and open colorectal surgery. We therefore used the American College of Surgeons (ACS) National Surgical Quality Improvement Program (NSQIP) procedure targeted colectomy cohort to determine whether OABP was associated with reduced postoperative SSI rates, LOS and readmission rates after elective colorectal surgery.
METHODS The study population consisted of all colectomy cases collected by the American College of Surgeons’ NSQIP in 2011 and 2012 for the Colectomy Targeted Participant Use Data File. Cases were collected across 121 NSQIP sites by trained surgical clinical reviewers.13 Patients were excluded from analysis if they were missing information on the type of preoperative preparation that was administered or if their surgery was identified as non-elective or emergent by NSQIP. A small number of cases were coded as clean cases and these were re-classified as clean contaminated as it is impossible for a colectomy to be a clean case. The primary outcomes measured were: (1) postoperative surgical site infection (SSI), (2) in-hospital LOS, and (3) all-cause readmission within 30 days after colectomy. A composite postoperative SSI was defined as the occurrence of a superficial, deep incisional, Annals of Surgery r Volume 261, Number 6, June 2015
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
Annals of Surgery r Volume 261, Number 6, June 2015
Oral Antibiotic Bowel Preparation
TABLE 1. Study Population Demographics and Comorbidities
None, N (%)
Mechanical Only, N (%)
OABP ± Mechanical, N (%)
8415 4288 (51.0) 4127 (49.0)
2150 (25.6) 1119 (52.1) 1031 (48.0)
3779 (44.9) 1939 (51.3) 1840 (48.7)
2486 (29.5) 1230 (49.5) 1256 (50.5)
6893 (81.9) 617 (7.3) 316 (3.8) 62 (52–72)
1658 (77.1) 174 (8.1) 66 (3.1) 62 (52–73)
3059 (81.0) 301 (8.0) 164 (4.3) 62 (52–72)
2176 (87.5) 142 (5.7) 86 (3.5) 61 (52–71)
7224 (85.9) 835 (9.9) 356 (4.2)
1861 (86.6) 182 (8.5) 107 (5.0)
3226 (85.4) 402 (10.6) 151 (4.0)
2137 (86.0) 251 (10.1) 98 (3.9)
6963 (82.8) 1452 (17.3)
1775 (82.6) 375 (17.4)
3141 (83.1) 638 (16.9)
2047 (82.3) 439 (17.7)
8255 (98.1) 127 (1.5) 14 (0.2)
2095 (97.4) 48 (2.2) 04 (0.2)
3708 (98.1) 54 (1.4) 08 (0.2)
2452 (98.6) 25 (1.0) 02 (0.1)
8040 (95.5) 375 (4.5)
2057 (95.7) 93 (4.3)
3603 (95.3) 176 (4.7)
2380 (95.7) 106 (4.3)
0.72
8373 (99.5) 42 (0.5)
2139 (99.5) 11 (0.5)
3760 (99.5) 19 (0.5)
2474 (99.5) 12 (0.5)
0.99
7838 (93.1) 553 (6.6) 24 (0.3)
1974 (91.8) 168 (7.8) 08 (0.4)
3517 (93.1) 251 (6.6) 11 (0.3)
2347 (94.4) 134 (5.4) 05 (0.2)
4436 (52.7) 3979 (47.3)
1161 (54.0) 989 (46.0)
1910 (50.5) 1869 (49.5)
1365 (54.9) 1121 (45.1)
0.001
8381 (99.6) 34 (0.4)
2138 (99.4) 12 (0.6)
3762 (99.6) 17 (0.5)
2481 (99.8) 05 (0.2)
0.13
7982 (94.9) 433 (5.2)
1989 (92.5) 161 (7.5)
3606 (95.4) 173 (4.6)
2387 (96.0) 99 (4.0)
