National Patterns of Urine Testing During Inpatient Admission.

Background: Overuse of urine testing is a driver of inappropriate antimicrobial use. Limiting wasteful testing is important for patient safety. We examined the national prevalence and patterns of urine testing during adult inpatient admission in the United States.

Methods: We performed a retrospective cohort study using a national dataset of inpatient admissions from 263 hospitals in the United States from 2009 to 2014. We included all adult inpatient admissions, excluding those related to pregnancy, urology procedures, and with lengths of stay >30 days. A facility-level fixed-effects quasi-Poisson regression model was used to examine the incidence of urinalysis and urine culture testing for select diagnoses and patient factors.

Results: The cohort included 4473655 admissions. Charges for urinalysis were present for 2086697 (47%) admissions, with 584438 (13%) including >1 urinalysis. Charges for urine culture were present for 1197242 (27%) admissions, with 246211 (6%) having >1 culture. Urine culture testing varied by principal diagnosis. Heart failure and acute myocardial infarction had 29% and 35% fewer cultures sent on the first day of admission compared to all other admissions (P < .001). Female sex and receipt of antibiotics during the hospital admission consistently predicted increased culture testing, regardless of principal diagnosis or age.

Conclusions: Urine testing was common and frequently repeated during inpatient admission, suggesting large-scale overuse. The variation in testing by diagnosis suggests that clinical presentation modifies test use. The sex bias in urine testing is not clinically supported and must be addressed in interventions aimed at reducing excess urine testing.