NURS 6231 Week 3 Outcome Measure Analysis Example

When Fewer Infections Produce a Higher Rate: An Analysis of the Catheter-Associated Urinary Tract Infection Measure

Student Name

College of Nursing, Walden University

NURS 6231: Healthcare Systems and Quality Outcomes

Instructor Name

Month Day, Year

When Fewer Infections Produce a Higher Rate: An Analysis of the Catheter-Associated Urinary Tract Infection Measure

Catheter-associated urinary tract infection (CAUTI) is one of the outcome measures a hospital's quality committee sees every quarter. Hospitals report it to the federal National Healthcare Safety Network (NHSN), and it is widely treated as a preventable harm. This analysis specifies the measure element by element using the NHSN definition, explains how facilities are compared, and then follows a composite medical unit through a successful catheter removal project. The analysis shows that the measure's denominator can make a real improvement look like a deterioration, and it recommends reporting the rate beside two companion figures so that the committee reads the unit's performance correctly.

Specifying the Measure

A measure can only be analyzed once each of its terms is fixed. The NHSN definition supplies those terms, and borrowing them has two advantages over a local version: the definition has been refined over years of surveillance, and results counted under it can be compared with other hospitals (Centers for Disease Control and Prevention [CDC], 2025). Table 1 sets out the elements.

Table 1

Elements of the CAUTI Measure Under the NHSN Definition

Two features matter for what follows. The denominator is catheter days, not patient days, so the rate describes risk among catheterized patients only. And the numerator depends on a urine culture being sent, so a unit that cultures more often will find more infections.

How Facilities Are Compared

Raw rates differ between units for reasons unrelated to the quality of care, since an intensive care unit and a rehabilitation unit carry different patients. NHSN therefore compares facilities through the standardized infection ratio, which divides the number of infections observed by the number predicted for a facility of that type, size and unit mix using national baseline data (CDC, 2025). A ratio of 1.0 means the facility had as many infections as predicted; 0.8 means 20% fewer. The ratio is not a rate. It carries no denominator of its own that a committee can inspect, and the prediction rests on catheter days, so it inherits the same sensitivity to the denominator examined below. Treating the ratio and the rate as interchangeable is one of the most common misreadings in committee minutes.

A Scenario: Improvement That Raises the Rate

Consider a composite 30-bed adult medical unit with about 2,700 patient days a quarter. At baseline, patients accumulate 600 catheter days a quarter, and the unit records three CAUTIs, a rate of 5.0 per 1,000 catheter days. Many catheters are placed in the emergency department for monitoring of urine output and then stay because no one is prompted to remove them.

The unit adopts a nurse-driven removal protocol: each shift, the nurse checks the catheter against a list of approved indications and removes it without a physician order when none applies. Protocols of this kind work. In a meta-analysis of 11 studies, reminders and stop orders cut CAUTI rates by 53% (Meddings et al., 2014), and a national prevention program reduced both catheter use and infection rates on non-intensive care units (Saint et al., 2016).

In the composite unit, catheter days fall by half, to 300 in the following quarter. The patients who still have catheters are different from those who had them before. They are the patients with urinary retention, those with stage 4 sacral wounds and those at the end of life, and their catheters stay in longer. Infections fall from three to two. The rate, however, is now two infections over 300 catheter days, or 6.7 per 1,000. The unit has one fewer infected patient and fewer patients exposed to a catheter at all, yet its reported rate has risen by a third. A committee reading only the rate would conclude that the unit's catheter care had deteriorated.

The scenario is not a claim that removal projects usually raise rates. The pooled studies show that they usually lower them (Meddings et al., 2014). It shows a property of the measure: because the denominator shrinks as care improves, and the remaining patients are at higher risk per day, the rate can move in either direction when outcomes for the unit as a whole improve.

Recommendation: Read Three Figures Together

The committee should see three figures side by side each quarter. The first is the rate per 1,000 catheter days, which describes risk among catheterized patients. The second is the count of infections, which tells how many patients were harmed. The third is the device utilization ratio, catheter days divided by patient days, which tells how often patients were exposed at all. In the scenario, utilization falls from 0.22 to 0.11, the count falls from three to two, and the rate rises. Read together, the three show an improving unit whose remaining catheterized patients are sicker. Fakih et al. (2016) argued for the utilization ratio as a performance measure in its own right, noting that it is objective, already captured in NHSN reporting and more directly tied to the goal of avoiding unnecessary catheters. A catheter can cause trauma, discomfort and immobility without any infection, and only the utilization ratio sees those harms.

Changing how the measure is reported costs almost nothing, since all three figures come from data already collected. It changes what the committee concludes.

What the Measure Cannot Show

The measure is silent about several things the committee might assume it covers. It does not count urinary infections in patients who were never catheterized, or in those whose catheter was in for two days or less. It does not capture infections that appear after discharge. Its numerator depends on culturing practice, so a unit that reduces unnecessary urine cultures will appear to improve even if nothing about catheter care changes. And it reflects surveillance criteria, which Fakih et al. (2016) noted correlate imperfectly with clinical infection. None of these limits argues against using the measure. They argue for stating them in the report so that the committee reads the figure for what it is.

Conclusion

Specified with care, the CAUTI measure is precise and comparable, and its per-catheter-day rate is the right figure for judging catheter care. It is the wrong figure for judging whether a unit is exposing fewer patients to catheters. Presented beside the infection count and the device utilization ratio, the rate tells the committee what it needs to know; presented alone, it can penalize the units that improve the most.

References

Centers for Disease Control and Prevention. (2025). National Healthcare Safety Network (NHSN) patient safety component manual. https://www.cdc.gov/nhsn/pdfs/pscmanual/pcsmanual_current.pdf

Fakih, M. G., Gould, C. V., Trautner, B. W., Meddings, J., Olmsted, R. N., Krein, S. L., & Saint, S. (2016). Beyond infection: Device utilization ratio as a performance measure for urinary catheter harm. Infection Control & Hospital Epidemiology, 37(3), 327-333. https://doi.org/10.1017/ice.2015.287

Meddings, J., Rogers, M. A. M., Krein, S. L., Fakih, M. G., Olmsted, R. N., & Saint, S. (2014). Reducing unnecessary urinary catheter use and other strategies to prevent catheter-associated urinary tract infection: An integrative review. BMJ Quality & Safety, 23(4), 277-289. https://doi.org/10.1136/bmjqs-2012-001774

Saint, S., Greene, M. T., Krein, S. L., Rogers, M. A. M., Ratz, D., Fowler, K. E., Edson, B. S., Watson, S. R., Meyer-Lucas, B., Masuga, M., Faulkner, K., Gould, C. V., Battles, J., & Fakih, M. G. (2016). A program to prevent catheter-associated urinary tract infection in acute care. New England Journal of Medicine, 374(22), 2111-2119. https://doi.org/10.1056/NEJMoa1504906