Protocolized Urine Sampling Reduces Catheter-Associated UTI

Protocolized urine sampling and testing significantly reduced catheter-associated urinary tract infection (CAUTI) rates and urinary catheter days, according to study results recently published in Clinical Infectious Diseases.

CAUTI is a preventable hospital-acquired condition. Currently, there are ~12% to 16% hospitalized adults with an indwelling urinary catheter. As the risk for CAUTI increases 3% to 7% per day of catherization and the cost of CAUTI ranges from $1000 to $10,000 per patient, the cost of CAUTI translates into millions of dollars of annual hospital expenses. Furthermore, although bacteriuria occurs at a rate of 3% to 10% per urinary catheter day, UTI symptoms develop in only 10% to 25% of bacteriuric patients, which suggests a high rate of colonization in the urinary catheter or bladder that is not clinically significant.

As most urine cultures are obtained for the nonspecific symptom of fever in patients with a low pretest probability of UTI, a high rate of false positive CAUTI diagnoses are expected. Furthermore, the current surveillance guidelines from the Centers for Disease Control and Prevention (CDC) and Centers for Medicare & Medicaid Services do not provide criteria to differentiate between urinary catheter/bladder colonization and CAUTI among symptomatic patients, which results in false-positive CAUTIs.

Although previous studies have identified intervention bundles that reduce CAUTI rates, it is unclear which elements of these bundles are most effective. Therefore, this study determined whether a protocol for urine collection designed to minimize detection of catheter colonization, in addition to standard CDC prevention measures, would reduce rates of CAUTI and urinary catheter days among high-risk patients. This is the first study to focus on a urine-sampling technique for lowering CAUTI rates.

This study included a pre- and post-intervention analysis (each had a 9-month duration) with a control group and was conducted at 2 campuses (test and control) of the same academic medical center. The test campus implemented a protocol that required the removal of the urinary catheter before obtaining a urine sample from a new catheter or sterile straight catheterization, along with urine bacteria and pyuria screening before culture. The control campus underwent only standard CDC prevention measures.

The primary outcomes were CAUTI rates compared between the pre- and post-intervention epoch in the test campus. Secondary outcomes included the percentage of reductions in CAUTI rates compared between the test campus and a propensity-score matched cohort at the control campus. Investigators included 7991 patients in the test campus primary analysis and 4264 patients in the propensity-score matched secondary analysis.

Results suggested that significantly reduced CAUTI rates and urinary catheter days were associated with protocolized urine sampling and testing aimed at minimizing contamination by colonization. Primary analysis results showed a reduction in CAUTI/1000 patients by 77% (P =.001), CAUTI/1000 catheter days by 63% (P =.001), and urinary catheter days/patient by 37% (P ≤.001). When compared with the control campus, the propensity score-matched analysis showed significant reduction at the test campus in CAUTI/1000 patients (57% vs 82%, respectively), CAUTI/1000 catheter days (57% vs 68%, respectively), and catheter-days/patient (1% vs 44%) (all, P <.001).

Overall, the study authors concluded, “We further demonstrated that our urine sampling protocol reduced catheter days as well, in part because once an indwelling catheter was removed to sample urine, many patients were identified as no longer requiring a catheter.”

Reference

Frontera JA, Wang E, Phillips M, et al. Protocolized urine sampling is associated with reduced catheter-associated urinary tract infections: a pre- and post-intervention study [published online August 10, 2020]. Clin Infect Dis. doi: 10.1093/cid/ciaa1152/5890408