Clinical inquiries. When are empiric antibiotics appropriate for urinary tract infection symptoms?

■ Evidence summary An evidence-based review found 5 highquality studies on the diagnosis of acute uncomplicated UTI among women. (“Uncomplicated” was defined as normal urinary tract and no contributing medical problems, such as diabetes, neurogenic bladder, renal stones.) UTIs were defined as the presence of significant bacteriuria (≥104 to 105 colony-forming units) on culture. A patient presenting to a clinician with 1 or more UTI symptoms had approximately a 50% chance of having significant bacteriuria on culture. The authors estimated the pretest probability of UTI as 5% from the incidence of asymptomatic bacteriuria among healthy women. This produced a LR+ of 19 simply for presenting to a clinician with 1 or more UTI symptoms. The summary LRs for clinical signs and symptoms in the prediction of UTI after presentation to the office are found in TABLE 2. A history of a vaginal discharge or irritation has a LR– of 0.3, decreasing the probability of UTI for a patient presenting to the office from approximately 50% to 20%, so further testing would be indicated. Healthy, nonpregnant women presenting with the triad of frequency, dysuria, and no vaginal symptoms have about a 96% chance of having an urinary tract infection (UTI) (positive likelihood ratio [LR+]=24.6). Since no urinalysis result would substantially change the high likelihood of disease for these patients, empiric therapy is appropriate (strength of recommendation [SOR]: B). A triage system based only on having 1 or more urinary symptoms is more sensitive but less specific: the chance of having a UTI drops to 50% (LR+ =19). While empiric therapy is still likely to be appropriate, rates of false positives and inappropriate antibiotic use may rise (SOR: B). Empiric treatment by telephone may also be considered (SOR: C). While no studies have specifically addressed the diagnostic value of UTI symptoms reported by phone, no increase in pyelonephritis or other adverse events has been seen with telephone treatment protocols. And while telephone treatment protocols can increase the use of guideline-recommended antibiotics and decrease costs, they may increase unnecessary antibiotic use overall. Contraindications to empiric therapy are listed in TABLE 1. Lauren DeAlleaume, MD, Elizabeth M. Tweed, BSN, MLIS University of Colorado Health Sciences Center, Denver