Amoxicillin/clavulanic acid versus cefotaxime for antimicrobial prophylaxis in abdominal surgery: a randomized trial

Mismatch of populations between randomised controlled trials of perioperative interventions in major abdominal surgery and current clinical practice

BACKGROUND

Demographics of patients undergoing major abdominal surgery are changing. External validity of relevant RCTs may be limited by participants not resembling patients encountered in clinical practice. We aimed to characterise differences in age, weight, BMI, and ASA grade between participants in perioperative trials in major abdominal surgery and patients in a reference real-world clinical practice sample. The secondary aim was to investigate whether time since trial publication was associated with increasing mismatch between these groups.

METHODS

MEDLINE and Embase were searched for multicentre RCTs from inception to September 2022. Studies of perioperative interventions in adults were included. Studies that limited enrolment based on age, weight, BMI, or ASA status were excluded. We compared trial cohort age, weight, BMI, and ASA distribution to those of patients undergoing major abdominal surgery at our tertiary referral hospital during September 2021 to September 2022. We used a local, single-institution reference sample to reflect the reality of clinical practice (i.e. patients treated by a clinician in their own hospital, rather than averaged nationally). Mismatch was defined using comparison of summary characteristics and ad hoc criteria based on differences relevant to predicted mortality risk after surgery.

RESULTS

One-hundred and six trials (44,499 participants) were compared to a reference cohort of 2792 clinical practice patients. Trials were published a median (IQR [range]) 13.4 (5-20 [0-35]) years ago. A total of 94.3% of trials were mismatched on at least one characteristic (age, weight, BMI, ASA). Recruitment of ASA 3 + participants in trials increased over time, and recruitment of ASA 1 participants decreased over time (Spearman's Rho 0.58 and - 0.44, respectively).

CONCLUSIONS

Patients encountered in our current local clinical practice are significantly different from those in our defined set of perioperative RCTs. Older trials recruit more low-risk than high-risk participants-trials may thus 'expire' over time. These trials may not be generalisable to current patients undergoing major abdominal surgery, and meta-analyses or guidelines incorporating these trials may therefore be similarly non-applicable. Comparison to local, rather than national cohorts, is important for meaningful on-the-ground evidence-based decision-making.

Association of antimicrobial perioperative prophylaxis with cefuroxime plus metronidazole or amoxicillin/clavulanic acid and surgical site infections in colorectal surgery

OBJECTIVE

To compare intravenous (IV) amoxicillin/clavulanic acid (A/CA) to IV cefuroxime plus metronidazole (C + M) for preventing surgical site infections (SSI) in colorectal surgery.

BACKGROUND

Given their spectra that include most Enterobacterales and anaerobes, C + M is commonly recommended as prophylaxis of SSI in colorectal surgery. A/CA offers good coverage of Enterobacterales and anaerobes as well, but, in contrast to C + M, it also includes Enterococcus faecalis which is also isolated from patients with SSI and could trigger anastomotic leakage.

METHODS

Data from a Swiss SSI surveillance program were used to compare SSI rates after class II (clean contaminated) colorectal surgery between patients who received C + M and those who received A/CA. We employed multivariable logistic regression to adjust for potential confounders, along with propensity score matching to adjust for group imbalance.

RESULTS

From 2009 to 2018, 27,922 patients from 127 hospitals were included. SSI was diagnosed in 3132 (11.2%): 278/1835 (15.1%) in those who received A/CA and 2854/26,087 (10.9%) in those who received C + M (p < 0.001). The crude OR for SSI in the A/CA group as compared to C + M was 1.45 [CI 95% 1.21-1.75]. The adjusted OR was 1.49 [1.24-1.78]. This finding persisted in a 1:1 propensity score matched cohort of 1835 patients pairs with an OR of 1.60 [1.28-2.00]. Other factors independently associated with SSI were an ASA score > 2, a longer duration of operation, and a reoperation for a non-infectious complication. Protective factors were female sex, older age, antibiotic prophylaxis received 60 to 30 min before surgery, elective operation, and endoscopic approach.

CONCLUSIONS

Despite its activity against enterococci, A/CA was less effective than C + M for preventing SSI, suggesting that it should not be a first choice antibiotic prophylaxis for colorectal surgery.

Oral and Parenteral vs. Parenteral Antibiotic Prophylaxis for Patients Undergoing Laparoscopic Colorectal Resection: An Intervention Review with Meta-Analysis

This study aims to systematically assess the efficacy of parenteral and oral antibiotic prophylaxis compared to parenteral-only prophylaxis for the prevention of surgical site infection (SSI) in patients undergoing laparoscopic surgery for colorectal cancer resection. Published and unpublished randomized clinical trials comparing the use of oral and parenteral prophylactic antibiotics vs. parenteral-only antibiotics in patients undergoing laparoscopic colorectal surgery were collected searching electronic databases (MEDLINE, CENTRAL, EMBASE, SCIENCE CITATION INDEX EXPANDED) without limits of date, language, or any other search filter. The outcomes included SSIs and other infectious and noninfectious postoperative complications. Risk of bias was assessed using the Cochrane revised tool for assessing risk of bias in randomized trials (RoB 2). A total of six studies involving 2252 patients were finally included, with 1126 cases in the oral and parenteral group and 1126 cases in the parenteral-only group. Meta-analysis results showed a statistically significant reduction of SSIs (OR 0.54, 95% CI 0.40 to 0.72; p < 0.0001) and anastomotic leakage (OR 0.55, 95% CI 0.33 to 0.91; p = 0.02) in the group of patients receiving oral antibiotics in addition to intravenous (IV) antibiotics compared to IV alone. Our meta-analysis shows that a combination of oral antibiotics and intravenous antibiotics significantly lowers the incidence of SSI compared with intravenous antibiotics alone.

[Pharmacoeconomic results of introducing antimicrobial prophylaxis in surgery at a university hospital]

OBJECTIVES

The introduction of antimicrobial prophylaxis in surgery was designed and pre-intervention (controls) and post-intervention (cases) evaluations were carried out at a university tertiary hospital.

PATIENTS AND METHOD

Prospective recording of information on prophylaxis in all patients undergoing non-emergency abdominal surgery was analysed during a 3-week period before and after implementing an antimicrobial prophylaxis program. Adequacy of prophylaxis was defined as prescription of antibiotics (type, dose and duration of treatment) according to the Guidelines.

RESULTS

In the pre-intervention study: included 36 patients; prophylaxis was inadequate in all patients (long-term in 22 cases; antibiotic class and long-term in 2 cases; antibiotic class, dose and long-term in 12 cases); mean duration of prophylaxis was 6 days (range 1 to 10 days); mean antibiotic cost per patient was 77 euro (range 9 to 412 euro); overall antibiotic cost for the 36 patients was 2770 euro. In the post-intervention study: included 37 patients: prophylaxis was inadequate in 11 patients (long-term in 10 cases; antibiotic class and long-term in 1 case); mean duration of prophylaxis was 2 days (range 1 to 9 days); mean antibiotic cost per patient was 16 euro (range 2 to 78 euro); overall antibiotic cost for the 37 patients was 593 euro. In the pre-intervention period antibiotic cost was 38 times higher than expected. In the post-intervention period it was 1.6 times higher than expected.

CONCLUSIONS

The most common reason of prophylaxis inadequacy is prolonged antibiotic treatment. A multidisciplinary intervention that comprises infectious diseases, surgical and pharmacy departments improves prophylaxis prescribing practice and avoids erroneous prescribing of antibiotics with both microbiological and economical cost savings.