Pyelonephritis in adult women: inpatient versus outpatient therapy

The traditional treatment of acute pyelonephritis has been hospitalization and parenteral administration of antibiotics. No previous study, however, has attempted to differentiate between those patients with pyelonephritis who might be safely managed as outpatients and those in whom hospitalization is required. We therefore decided to determine whether women with pyelonephritis can be effectively and safely managed outside the hospital.

The medical records of 94 female outpatients and 100 hospitalized women treated for acute pyelonephritis at San Francisco General Hospital were reviewed. Utilizing baseline clinical and laboratory data, we compared outcome in the two groups, and computed the cost-benefit of managing pyelonephritis on an outpatient basis.

We observed a similarity in the frequency of successful outcomes (approximately 90 percent in each group) and absence of serious adverse outcome in any outpatient. Results of urine culture were comparable in inpatients and outpatients, with Escherichia coli identified as the most common urinary pathogen in both groups. The frequency of resistance to ampicillin of E. coli and other urinary pathogens was nearly 30 percent. A cost analysis demonstrated a 7.5-fold difference between the inpatient and outpatient groups.

Our findings suggest that treatment of pyelonephritis with oral antibiotics poses a safe and effective method of therapy in immunocompetent women without underlying illness. The use of ampicillin as a single agent for the treatment of pyelonephritis, however, is inadvisable. Our study also demonstrates the potential savings in managing selected patients with pyelonephritis as outpatients.