Factors Predicting Catheter-Associated Urinary Tract Infections Among General Medical and Critically Ill Patients

Abstract

Introduction Urinary tract infections (UTIs) are among the most common hospital-acquired infections, with approximately 75% associated with indwelling urinary catheters, referred to as Catheter-Associated Urinary Tract Infections (CAUTIs). These infections contribute to increased morbidity, healthcare costs, and length of hospital stay. According to the Centers for Disease Control and Prevention (CDC), CAUTIs are classified into symptomatic urinary tract infections and asymptomatic bacteriuria. Both categories require a history of catheterization for more than two calendar days or of catheter removal within one calendar day, together with urine culture results that meet the specified criteria. Prolonged catheterization and suboptimal catheter care are recognized as major risk factors. At Songklanagarind Hospital, the incidence of CAUTIs remains above the institutional benchmarks, particularly among general medical and critically ill patients. Although several risk factors have been reported, evidence specific to medical patients whose clinical conditions and care practices differ from those of other groups remains limited. This study, therefore, aims to identify risk factors for CAUTIs to strengthen surveillance efforts and inform the development of nursing practice guidelines to enhance patient safety.

Objectives The objectives of this study were twofold: 1) to determine the incidence of catheter-associated urinary tract infections (CAUTIs) among general medical and critically ill patients, and 2) to investigate factors predicting CAUTIs in general medical and critically ill patients.

Design This study employed a retrospective analytical design, guided by the epidemiological framework of infectious diseases, which explains infection as a consequence of imbalance among three principal factors: 1) host factors, 2) agent factors, and 3) environmental factors. Applied to catheter-associated urinary tract infections (CAUTIs), these three domains contribute to the increased risk of infection. However, the present study focused specifically on host and environmental factors associated with CAUTIs, as pathogen-related factors involve microbiological data that fall beyond the scope of this investigation.

Methodology Data were retrieved from the information system of Songklanagarind Hospital. The study participants comprised medical patients admitted to general medical wards and intensive care units, aged 18 years or older, who had indwelling urinary catheters for more than two calendar days. Data were collected retrospectively from patients admitted between July 2024 and April 2025, yielding a total of 848 cases. The research instrument was a data collection form developed by the investigator based on a literature review, with a content validity index (CVI) of .98. Prior to formal data collection, the form was pilot tested with a subset of medical records to ensure completeness and consistency of documentation. Data analysis employed descriptive statistics. The incidence of CAUTIs was compared between general medical and critically ill patients using the Chi-square test, with CAUTI incidence calculated as infections per 1,000 catheter-days. Risk factors associated with CAUTIs were analyzed using the Wilcoxon rank-sum test, Chi-square test, or Fisher’s exact test, as appropriate. Factors predicting CAUTIs were further examined using multiple logistic regression analysis.

Results The participants had a mean age of 69 years (SD = 17.61). The mean duration of urinary catheterization was 6.37 days (SD = 4.45). The overall incidence of CAUTIs was 3.70 per 1,000 catheter-days. The incidence rates among general medical patients and critically ill patients were 3.45 and 4.07 per 1,000 catheter-days, respectively, with no statistically significant difference (p = .500). The majority of causative organisms were Gram-negative bacteria, with Klebsiella pneumoniae being the most common (25%), followed by Pseudomonas aeruginosa (20.8%) and Escherichia coli (12.5%). Risk factor analysis revealed significant associations between CAUTIs and a history of urinary tract infection within the past six months (p = .013), duration of catheterization (p < .001), catheter insertion in inpatient wards (p = .020), catheter reinsertion (p = .022), length of hospital stay (p = .001), and diarrhea (p = .005). Multiple logistic regression analysis identified three significant predictors of CAUTIs: (1) duration of catheterization, with each additional day increasing the risk by 19% (OR = 1.190, 95% CI: 1.110–1.290, p < .001); (2) catheter insertion in inpatient wards, which carried a 10.68-fold higher risk compared with insertion in the emergency department or operating room (OR = 10.680, 95% CI: 1.760–228.530, p = .040); and (3) diarrhea, which increased the risk of CAUTIs by 3.26 times compared with normal bowel function (OR = 3.260, 95% CI: 1.170–10.010, p = .028).

Recommendation Nurses and multidisciplinary teams can apply the findings of this study to guide strategies for preventing CAUTIs. Prevention efforts should emphasize systematic reduction of catheterization duration, coupled with continuous reassessment of catheter necessity, particularly among patients with diarrhea who are at elevated risk of CAUTIs. In addition, catheter insertion practices in inpatient wards should be reviewed and standardized to minimize the risk of contamination during the procedure. Implementation of these measures will help reduce catheter-related complications, strengthen infection prevention protocols, lower the incidence of CAUTIs among hospitalized patients, and ultimately enhance patient safety and overall quality of care.