Early Antibiotic Therapy Does Not Improve Mortality in Patients with CAUTI

The overuse of antibiotics for treating urinary tract infections has led to drug resistance and inadvertent adverse drug events that require effective antibiotic stewardship interventions.

Catheter-associated urinary tract infections (CAUTIs) account for about 40% of all nosocomial infections in hospitals and nursing homes. Patients with indwelling catheters are usually colonized with multidrug-resistant (MDR) organisms, so that when they require treatment, broad-spectrum antibiotics are prescribed. Clinicians tend to overtreat urinary tract infections (UTIs), especially in the elderly, because some patients may not complain and can present with nonspecific symptoms of infections (eg, change in mental status). Therefore, with multiple courses of unnecessary antibiotics, drug resistance develops over time. Babich et al conducted a prospective cohort study in a large hospital assessing whether early (within 48 hours) appropriate empirical antibiotics can improve survival in patients with CAUTIs. The primary outcomes were 30-day all-cause mortality and long-term survival up to 4 years. The secondary outcomes were length of hospital stay, length of febrile illness, clinical failure, and rehospitalization within 30 days.

A total of 315 hospitalized adult patients with >7 days of indwelling catheters, pyuria, bacteriuria, and at least 2 markers of systemic inflammation were included in the study, which was conducted between August 2010 and February 2015. The majority were elderly patients (mean age, 79 years) and had chronic illnesses. About 25% of the patients (77) had bacteremia and 55% (174) had MDR gram-negative bacteria.

Forty-nine percent of patients (155) received appropriate antibiotics, defined as active drugs against the isolated organism that were started before culture results were available and within 48 hours of the index point. The 30-day crude mortality rate of the cohort was about 31%. Patients receiving appropriate antibiotics had a 30-day mortality rate on univariate analysis of 32.9% (51) compared with 28.8% (46) of patients receiving inappropriate antibiotics (P = .425).

The overall median survival was 82 days (interquartile range [IQR], 22-638). Survival decreased to 48 days in patients older than 85 years (IQR, 11-333; P = .001). Use of early appropriate empirical antibiotics did not impact short-term survival, even in the subgroup of patients with Enterobacteriaceae bacteremia (odds ratio [OR] for 30-day mortality with appropriate antibiotics, 0.73, 95% CI, 0.28-1.87). Instead, older age (OR, 1.04 per 1-year increment; 95% CI, 1:01-1.07), congestive heart failure (OR, 2.08; 95% CI, 1.16-3.73), malignancy (OR, 2.18; 95% CI, 1.13-4.2), and sepsis-related organ failure assessment score (SOFA score) on presentation (OR, 1.23 per an increment of 1 in the score; 95% CI, 1.1-1.36) were found to be independent predictors of 30-day mortality on multivariate analysis. Similarly, the use of appropriate antibiotic therapy did not affect long-term survival, although old age, previous antibiotic use, place of residence, nasogastric tube, increased SOFA score and Charlson Comorbidity Index score did have an effect. Furthermore, there was no significant impact between appropriate empirical antibiotics and all secondary outcomes seen in the study.

The authors mentioned that their results differed from other studies wherein inappropriate antibiotics led to a higher risk of mortality. They speculated that older age, multiple comorbidities, or difficulty distinguishing between a symptomatic UTI and other febrile illnesses caused by nonurinary source of infections in patients with indwelling catheters may have attributed to their study results. Study limitations included a single center with a high prevalence of MDR pathogens, treatment decisions based on providers’ discretion, and many patients with comorbidities.

Nonetheless, based on their study, the authors suggest that patients with suspected CAUTIs with no other source of infection can be observed off antibiotics until the cause of fever or sepsis is further assessed. Clinicians should take time to fully evaluate their patients clinically and microbiologically prior to prescribing antibiotics, mainly because early appropriate empirical antibiotics did not affect survival outcomes. Such strategy can limit the overuse of broad-spectrum antibiotics and focus more on directed therapy, which then helps antibiotic stewardship in hospitals and nursing homes. However, withholding antibiotics for up 48 hours may not be reasonable for all patients. Patients who are not medically stable, who are severely ill with septic shock, may require earlier treatment especially if they are already at high risk for mortality. More studies are needed to further stratify patients for whom early appropriate antibiotics will be beneficial.

Maricelle O. Monteagudo-Chu, PharmD, BCPS AQ-ID is an antimicrobial stewardship pharmacist at Northwell Health Mather Hospital in Port Jefferson, NY.

Reference:

Babich T, Zusman O, Elbaz M et al. Empirical antibiotic treatment does not improve outcomes in catheter-associated urinary tract infection: prospective cohort study. Clin Infect Dis. 2017;65(11):1799-1805. doi: 10.1093/cid/cix680.