Should emergentologists follow up on patients diagnosed with UTI having negative urine cultures? Implications for processing post-discharge laboratory results.

Abstract

After patients are discharged from the emergency department (ED), follow-up of test results focuses on abnormal values. In the elderly, non-specific symptoms can result in an incorrect diagnosis of urinary tract infection (UTI). This study compared the outcomes of patients discharged from the ED with a diagnosis of UTI based on urine culture results. We conducted a retrospective cohort study using linked health databases and chart review of a random sample of elderly patients (age>65years) discharged from the Ottawa Hospital ED between 2006 and 2014 with a diagnosis of UTI. Patients were categorized based on whether urine cultures were positive and bacterial sensitivity to prescribed antibiotics. Primary outcome was return to ED, admission to hospital, or death within 30days. A total of 1001 patients were included in the study (401 culture-negative; 474 culture-positive antibiotic-sensitive; 126 culture positive antibiotic-insensitive). Patients were elderly (mean age 80years, SD 7.6) with a high prevalence of dementia (18.0%). Almost a third of patients (n=313, 31.3%) experienced an outcome. Compared to culture-positive antibiotic-sensitive patients, culture negative patients (adjOR 1.45, 95% CI 1.07-1.97) and culture-positive antibiotic-insensitive patients (adjOR 1.49, 95% CI 0.90-2.14) were significantly more likely to experience an outcome (P=0.04). Patients discharged from the ED with a diagnosis of UTI have an increased risk of return to ED, urgent readmission or death if the uropathogen is insensitive to the prescribed antibiotic or if the culture is negative. Patients diagnosed with UTI with a negative culture may need further assessment.