Comparison of intravenous versus combined oral and intravenous antimicrobial prophylaxis (COMBINE) for the prevention of surgical site infection in elective colorectal surgery: study protocol for a multicentre, double-blind, randomised controlled clinical trial

A framework for the definition and interpretation of the use of surrogate endpoints in interventional trials

Background

Interventional trials that evaluate treatment effects using surrogate endpoints have become increasingly common. This paper describes four linked empirical studies and the development of a framework for defining, interpreting and reporting surrogate endpoints in trials.

Methods

As part of developing the CONSORT (Consolidated Standards of Reporting Trials) and SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) extensions for randomised trials reporting surrogate endpoints, we undertook a scoping review, e-Delphi study, consensus meeting, and a web survey to examine current definitions and stakeholder (including clinicians, trial investigators, patients and public partners, journal editors, and health technology experts) interpretations of surrogate endpoints as primary outcome measures in trials.

Findings

Current surrogate endpoint definitional frameworks are inconsistent and unclear. Surrogate endpoints are used in trials as a substitute of the treatment effects of an intervention on the target outcome(s) of ultimate interest, events measuring how patients feel, function, or survive. Traditionally the consideration of surrogate endpoints in trials has focused on biomarkers (e.g., HDL cholesterol, blood pressure, tumour response), especially in the medical product regulatory setting. Nevertheless, the concept of surrogacy in trials is potentially broader. Intermediate outcomes that include a measure of function or symptoms (e.g., angina frequency, exercise tolerance) can also be used as substitute for target outcomes (e.g., all-cause mortality)-thereby acting as surrogate endpoints. However, we found a lack of consensus among stakeholders on accepting and interpreting intermediate outcomes in trials as surrogate endpoints or target outcomes. In our assessment, patients and health technology assessment experts appeared more likely to consider intermediate outcomes to be surrogate endpoints than clinicians and regulators.

Interpretation

There is an urgent need for better understanding and reporting on the use of surrogate endpoints, especially in the setting of interventional trials. We provide a framework for the definition of surrogate endpoints (biomarkers and intermediate outcomes) and target outcomes in trials to improve future reporting and aid stakeholders' interpretation and use of trial surrogate endpoint evidence.

Funding

SPIRIT-SURROGATE/CONSORT-SURROGATE project is Medical Research Council Better Research Better Health (MR/V038400/1) funded.

Effect of oral antimicrobial prophylaxis on surgical site infection after elective colorectal surgery: multicentre, randomised, double blind, placebo controlled trial

OBJECTIVE

To investigate whether oral antimicrobial prophylaxis as an adjunct to intravenous antibiotic prophylaxis reduces surgical site infections after elective colorectal surgery.

DESIGN

Multicentre, randomised, double blind, placebo controlled trial.

SETTING

11 university and non-university hospitals in France between 25 May 2016 and 8 August 2019.

PARTICIPANTS

926 adults scheduled for elective colorectal surgery.

INTERVENTION

Patients were randomised to receive either a single 1 g dose of ornidazole (n=463) or placebo (n=463) orally 12 hours before surgery, in addition to intravenous antimicrobial prophylaxis before surgical incision.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of patients with surgical site infection within 30 days after surgery. Secondary outcomes included individual types of surgical site infections and major postoperative complications (Clavien-Dindo classification grade 3 or higher) within 30 days after surgery.

RESULTS

Of the 960 patients who were enrolled, 926 (96%) were included in the analysis. The mean age of participants was 63 years and 554 (60%) were men. Surgical site infection within 30 days after surgery occurred in 60 of 463 patients (13%) in the oral prophylaxis group and 100 of 463 (22%) in the placebo group (absolute difference -8.6%, 95% confidence interval -13.5% to -3.8%; relative risk 0.60, 95% confidence interval 0.45 to 0.80). The proportion of patients with deep infections was 4.8% in the oral prophylaxis group and 8.0% in the placebo group (absolute difference -3.2%, 95% confidence interval -6.4% to -0.1%). The proportion of patients with organ space infections was 5.0% in the oral prophylaxis group and 8.4% in the placebo group (absolute difference -3.4%, -6.7% to -0.2%). Major postoperative complications occurred in 9.1% patients in the oral prophylaxis group and 13.6% in the placebo group (absolute difference -4.5%, -8.6% to -0.5%).

CONCLUSION

Among adults undergoing elective colorectal surgery, the addition of a single 1 g dose of ornidazole compared with placebo before surgery significantly reduced surgical site infections.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02618720.

Oncologic colorectal surgical site infection: oral or not oral antibiotic preparation, that is the question

PURPOSE

Surgical wound infection is the most frequent postoperative complication in abdominal surgery, especially at the colorectal level. The aim of this study is analysing the results of mechanical colon preparation combined with oral antibiotic versus mechanical colon preparation without antibiotic therapy in patients with colorectal cancer undergoing elective surgery.

METHODS

This retrospective cohort study had been developed from November 2017 to February 2020. We have included a total of 281 consecutive patients undergoing elective colon and rectal oncological surgeries by the same surgical group using laparoscopic and open approaches. Transanal minimally invasive surgery (TAMIS) and transanal total mesorectal excision (TaTME) approaches were excluded. Exposed patients undergoing colon and rectal cancer surgery received mechanical bowel preparation and oral antibiotics with three doses of neomycin 1 g and erythromycin 500 mg the day before surgery.

RESULTS

The primary outcome was reduction in surgical wound infection rates before and after starting the oral antibiotic therapy from 17 to 6% (p < 0.05). As a secondary analysis, we evaluated the anastomotic dehiscence rate, corresponding with a decrease from 12 to 3% (p < 0.05).

CONCLUSION

Mechanical bowel preparation combined with oral antibiotic therapy is still not unanimously carried out in all the medical hospitals. In this report, we show that mechanical bowel preparation in combination with oral antibiotic reduces the risk of surgical wound infection and anastomotic leakage in patients undergoing colon and rectal cancer surgery.

Impact of oral antibiotic prophylaxis on surgical site infection after rectal surgery: results of randomized trial

AIM

To evaluate the impact of oral antibiotic prophylaxis on surgical site infection (SSI) rate after rectal surgery.

METHODS

It was a single-center 1:1 randomized controlled open parallel trial (registration number NCT03436719). The patients undergoing rectal resection for benign and malignant tumors were assigned randomly to two groups: the oral plus intravenous (IV) antibiotic prophylaxis (AP) and the IV antibiotic prophylaxis only. The primary endpoint was the overall rate of SSI.

RESULTS

Between November 2017 and December 2018, 116 (male-55, the mean age-64 years) patients were enrolled into the trial. Of them, 57 had oral erythromycin 500 mg + metronidazole 500 mg a day before surgery and 1,000 mg of cephalosporin IV 30-90 min before operation. In the other group, 59 patients had the same IV antibiotics only. The incidence of SSIs was 22% (13/59) and 3.5% (2/57) correspondingly (р = 0.002). The statistically significant difference was detected for superficial SSI 0 (0%) vs. 5 (8.5%) (p = 0.03) and organ/space SSI 2 (3.5%) vs. 9 (15.3%) (p = 0.03), respectively. A multivariate analysis of risk factors of SSI identified two independent ones: bacterial contamination of the pelvic cavity ≥ 10⁵ CFU at the end of surgery OR 17.9, 95% CI 2.1-150.0 (p = 0.008) and oral antimicrobial prophylaxis OR 0.2, 95% CI 0.03-0.8 (p = 0.02).

CONCLUSION

Oral-parenteral AP significantly reduced the risk of SSI following elective rectal surgery. Bacterial contamination of the pelvic cavity ≥ 10⁵ CFU at the end of surgery and oral antimicrobial prophylaxis were independent risk factors of SSI.