Urine Culturing Practices in U.S. Acute Care Hospitals, 2017-2020 Open Access

Asonganyi, Nyawung (Lillian) (Spring 2023)

Permanent URL: https://etd.library.emory.edu/concern/etds/br86b5165?locale=en
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Abstract

Background: Urinary tract infections (UTI) are common among hospitalized patients. However, these infections are often overdiagnosed due to excessive urine culturing. Urinalysis tests that precede a urine culture can effectively rule out a UTI and decrease the misuse of urine cultures. However, it is unclear to what extent this practice is used throughout the United States and what factors are associated with inappropriate urine culturing. In this study, we will examine changes in urine culturing with respect to urinalysis test results over time and identify patient and hospital characteristics associated with suboptimal practice.

 

Methods: Urine cultures were identified using microbiology tables from the PINC AI Healthcare Database (PHD). Only the first urine culture performed per hospitalization was included. The cohort excluded urine cultures from pregnant or urological procedure patients. Cultures were further categorized into the following groups based on identified urinalysis tests performed within 24 hours of the culture: appropriate (urine culture with positive urinalysis), potentially unnecessary (urine culture with negative urinalysis), and potentially inappropriate (urine culture without urinalysis). The frequency of urine culture categories by patient and hospital characteristics are reported. A modified Poisson regression was employed to describe the patient and hospital characteristics associated with potentially unnecessary/inappropriate urine cultures.

 

Results: 1.2 million urine cultures were identified from 279 PHD hospitals. From 2017 to 2019, the frequency of appropriate urine cultures increased from 60.5% to 68.2%, potentially inappropriate urine cultures decreased from 19.3% to 10.5%, and potentially unnecessary urine cultures remained at about 21%. The strongest predictors for potentially unnecessary/inappropriate urine cultures were male gender (Risk ratio [RR] 1.34, 95% Confidence Interval [CI] 1.30-1.38), performed after day 3 of hospitalization (RR 1.25, 95% CI 1.19-1.30), cancer (RR 1.08, 95% CI 1.06-1.10), and Medicaid status (RR 1.02, 95% CI 1.01-1.03). Older age and diabetes were protective against potentially unnecessary/inappropriate urine cultures. No hospital characteristics were significantly associated with these cultures.

 

Conclusion: In our cohort, appropriate urine culture use increased over time, but suboptimal use remains common. This study also identifies potential areas of improvement in urine culture diagnostic stewardship practice.

Table of Contents

 Introduction 1

Urinary Tract Infections and Methods of Diagnosis 1

Overuse of Urine Cultures 2

Impact of Urine Culture Overutilization on Patient Outcomes 3

Diagnostic Stewardship of Urine Cultures 4

Leveraging Healthcare Databases to Understand Urine Culturing Practices 7

Study Aims 7

Methods 8

Study Design, Population, and Data Source 8

Urine Culture Identification and Selection 8

Outlier Detection 9

Urine Culture Eligibility Criteria 10

Identification of Urinalysis Tests 10

Urine Culture – Urinalysis Linkage 11

Urinalysis Test Result Evaluation 11

Outcome Definition and Measurement 12

Covariates 12

Analytical Approach 13

Results 14

Characteristics of Urine Cultures. 14

Multivariable Analysis. 17

Discussion 18

Strengths and Limitations 22

Conclusion 23

References 24

Figures and Tables 32

Supplementary Material 41

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