Practice variation in treatment of suspected asymptomatic bacteriuria prior to cardiac surgery: are there differences in postoperative outcome? A retrospective cohort study

If you don't test, they will not treat: Impact of stopping preoperative screening for asymptomatic bacteriuria

Objective

Screening for asymptomatic bacteriuria (ASB) is not recommended outside of patients undergoing invasive urological procedures and during pregnancy. Despite national guidelines recommending against screening for ASB, this practice is prevalent. We present outcomes from a quality-improvement intervention targeting patients undergoing cardiac artery bypass grafting surgery (CABG) at Massachusetts General Hospital, a tertiary-care hospital in Boston, Massachusetts, where preoperative testing checklists were modified to remove routine urinalysis and urine culture. This was a before-and-after intervention study.

Methods

Prior to the intervention, screening for ASB was included in the preoperative check list for all patients undergoing CABG. We assessed the proportion of patients undergoing screening for ASB in the 6 months prior to and after the intervention. We estimated cost savings from averted laboratory analyses, and we evaluated changes in antibiotic prescriptions. We additionally examined the incidence of postoperative surgical-site infections (SSIs), central-line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs) and Clostridioides difficile infections (CDIs).

Results

Comparing the pre- and postintervention periods, urinalyses decreased by 76.5% and urine cultures decreased by 87.0%, with an estimated cost savings of $8,090.38. There were 50% fewer antibiotic prescriptions for bacteriuria after the intervention.

Conclusions

Removal of urinalysis and urine culture from preoperative checklists for cardiac surgery led to a statistically significant decrease in testing without an increase in SSIs, CLABSIs, CAUTIs, or CDI. Challenges identified included persistence of checklists in templated order sets in the electronic health record.

Association of Screening and Treatment for Preoperative Asymptomatic Bacteriuria With Postoperative Outcomes Among US Veterans

Importance

Limited data suggest that screening for asymptomatic bacteriuria (ASB) prior to nonurologic procedures is not useful. However, high-quality evidence to support consensus recommendations and influence clinical practice is lacking.

Objective

To characterize the association between detection and treatment of preoperative ASB and postoperative outcomes.

Design, Setting, and Participants

This retrospective cohort study involved patients, predominantly male veterans, who underwent surgical procedures in 109 US facilities within the US Department of Veterans Affairs health care system from October 1, 2008, to September 30, 2013. Participants included patients (n = 68 265) who had cardiac, orthopedic, or vascular surgical procedures. Each received a planned clinician review of complete medical records for antimicrobial prophylaxis as well as 30-day surgical-site infection (SSI) and urinary tract infection (UTI) outcomes, and each had a preoperative urine culture result available within the 30 days prior to the procedure. Data analysis was performed from December 2016 to August 2018.

Main Outcome and Measures

The primary outcome was the association between preoperative ASB and postoperative SSI. The secondary outcomes included postoperative UTI and the association between antimicrobial therapy for ASB and postoperative infectious outcomes.

Results

In total, 68 265 patients (65 664 [96.2%] were men and 2601 [3.8%] were women, with a mean [SD] age of 64.6 [9.2] years) were identified, and 17 611 (25.8%) were eligible for inclusion in the primary analysis. Preoperative urine cultures were performed in 17 749 (26.0%) patients, and the results were positive in 755 (4.3%), of which 617 (81.7%) were classified as ASB. With adjustments for age, American Society of Anesthesiologists class, smoking status, race/ethnicity, sex, and diabetes status, patients with or without ASB had similar odds of SSI (2.4% vs 1.6%; adjusted odds ratio [aOR], 1.58; 95% CI, 0.93-2.70; P = .08). Receipt of antimicrobial therapy with activity against the ASB organism was not associated with a reduced SSI risk (aOR, 1.01; 95% CI, 0.28-3.65; P = .99). Urinary tract infection occurred in 14 (3.3%) of 423 patients with ASB and 196 (1.5%) of 12 913 patients without ASB (aOR, 1.42; 95% CI, 0.80-2.49; P = .22). Treatment or prophylaxis for the ASB organism similarly was not associated with reduced odds of postoperative UTI (aOR 0.68; 95% CI, 0.20-2.30; P = .54). The ASB organisms matched a postoperative wound culture in 2 cases, both Staphylococcus aureus.

Conclusions and Relevance

The findings of this study suggest that receipt of antimicrobial therapy with activity against ASB organisms identified in preoperative urine cultures was not associated with reductions in the risk for postoperative infections, including UTI and SSI; such findings suggest there is evidence for discontinuing the practice of screening and treatment for preoperative ASB.

Bacteriuria is not associated with surgical site infection in patients undergoing cardiovascular surgery

BACKGROUND

Despite absence of evidence, in practice, asymptomatic bacteriuria is perceived as a risk factor for surgical site infection (SSI) among patients with cardiac surgery. We aimed to identify whether an association exists between the preoperative presence of asymptomatic bacteriuria or urinary tract infection and SSI in patients undergoing cardiovascular surgery.

METHODS

This is an analytical study with a retrospective cohort of patients undergoing coronary revascularization or valve replacement surgery. We identified cases of bacteriuria, urinary tract infection, and cardiovascular SSI and adjusted the results according to exposure to antibiotics and known risk factors for SSI using a multivariate logistic regression analysis.

RESULTS

A total of 840 patients were included in the study, of whom 33 (3.9%) had asymptomatic bacteriuria and 13 (1.5%) had urinary tract infections. The incidence of SSI was 9.5% (80 patients), with 2.3% of cases having mediastinitis. In the multivariate analysis, asymptomatic bacteriuria (relative risk, 0.83; 95% confidence interval, 0.26-2.56; P = .74) and urinary tract infection (relative risk, 2.54; 95% confidence interval, 0.60-10.69; P = .20) were not risk factors for SSI. Traditional risk factors were found to increase the risk of SSI.

CONCLUSIONS

The presence of bacteriuria is not a risk factor for presenting SSI in cardiovascular surgery. Screening with urinalysis or urine culture would not be recommended for patients undergoing cardiac surgery.