No need for a urine culture in elderly hospitalized patients with a negative dipstick test result

To determine the clinical utility/disutility of canceling urine cultures in elderly patients with a negative dipstick. The cohort included consecutive patients aged ≥ 65 years hospitalized in internal medicine departments with an admission urinalysis and urine culture (January 1, 2014 to December 31, 2016). We calculated the sensitivity of the dipstick (either a trace leukocyte esterase or a positive nitrite test result) to detect patients with bacteriuria, and the decrease in urine cultures resulting from cancelation in patients with a negative dipstick. We reviewed the charts of patients with a positive culture but negative dipstick to determine if they received appropriate antibiotic therapy and if the culture results had clinical utility, defined as changes in antibiotic therapy made according to culture results in a patient who did not respond to initial antibiotic therapy. The sensitivity of the dipstick for bacteriuria was 90.8% (95% CI, 89.6-92.0%). Of the 210 patients with a positive culture but negative dipstick, 132 (62.9%) had a diagnosis clearly outside the urinary tract. Thirty-five patients (16.7%) received inappropriate differential antibiotic therapy. Urine cultures did not have clinical utility and canceling urine cultures in those with a negative dipstick would result in a 41.5% (95% CI, 40.3-42.7%) decrease in urine cultures. We conclude that canceling orders for urine cultures in the elderly patient with a negative dipstick did not have clinical disutility and would decrease inappropriate antibiotic therapy. Extrapolation to other settings is dependent on urinalysis methodology, patient selection, and physician ordering and treatment behaviors.